CN102186123B - Multicast-sharing and multilayer protection method based on subtrees in WDM (wavelength division multiplexer) optical network, - Google Patents

Abstract

The invention provides a multicast-sharing and multilayer protection method based on subtrees in a WDM (wavelength division multiplexer) optical network, belonging to the technical field of network communications. The method comprises the steps of: establishing a working multicast forest, establishing a protection multicast forest, protecting a WDM layer and leaving services. In the method, under the premise of considering single-link faults, a multicast-sharing protection method is constructed on the basis of the subtrees, a subtree-protecting resource sharing strategy, a light-path resource sharing strategy and a wavelength link protecting resource sharing strategy are adopted according to differences of shared grain sizes, so that the quantity of damaged services when a physical link generates faults is reduced, the application range of the traditional multicast-sharing and multilayer protection method can be expanded, multiple constraining conditions are considered when multilayer protection is carried out, and the multicast-sharing and multilayer protection method is provided under multiple strategies.

Description

Multi-layer protection method is shared in the multicast based on subtree in a kind of WDM optical-fiber network

Technical field

The invention belongs to networking technology area, multi-layer protection method is shared in the multicast based on subtree being specifically related in a kind of WDM optical-fiber network.

Background technology

Along with the high speed development of the Internet, people have proposed new requirement to the capacity of communication system and performance.Wavelength division multiplexing (Wavelength Division Multiplexing, WDM) technology can provide huge transmission capacity, meets the demand of Internet service to bandwidth.But, once there is network failure, will cause a large number of services to interrupt.Meanwhile, in order to reduce network operation cost, improve bandwidth resources utilance, transmission network is developed to IP over WDM double-layer structure by traditional IP over ATM over SDH/SONET overWDM multiple-layer overlapped structure gradually, and IP operation is directly carried on WDM optical-fiber network.

Multi-layer protection method is shared in multicast in traditional optical-fiber network; mostly only consider the shared multi-layer protection method of link failure under single restraint condition; its scope of application is narrower; do not consider the multiple constraint situations such as the constraint of optical transceiver number, sparse wavelength conversion constraint, do not consider the recovery amount of action reducing when breaking down and the resource utilization that improves light path yet.

Summary of the invention

The problem existing for above-mentioned prior art; multi-layer protection method is shared in the multicast based on subtree the invention provides in a kind of WDM optical-fiber network; the method is being considered under the prerequisite of single link failure; based on subtree, built multicast share protect method; according to shared granularity difference, take subtree reserved resource sharing policy, light path reserved resource sharing policy and wavelength span reserved resource sharing policy, reduce the quantity of the impaired business when physical link breaks down.

Multi-layer protection method is shared in the multicast based on subtree in WDM optical-fiber network of the present invention, comprises the steps:

Step (1), set up work multicast forest

Adopt multicast service amount congestion relief algorithm for asking to set up work multicast forest; If multicast service amount congestion relief algorithm is dredged unsuccessfully, algorithm finishes so.

Step (2), foundation protection multicast forest

The physical link of step (2.1), light path is separated

Wavelength span on each physical link of light path process is set, through the light path of these wavelength spans and the cost of subtree, is set to ∞;

The physical link of step (2.2), subtree is separated

Step (2.2.1), by formula

the cost W of light tree is set _st,

By formula

the cost W of light path is set _ll,

Search the destination node of dredging by this subtree;

Wherein: b _t, b _w, b _p, b _newif represent respectively, total bandwidth, bandwidth of operation, protection bandwidth and the protection multicast forest of this light path are through the newly assigned protection bandwidth of these light path needs number, α _llthe grade factor for logical links;

Step (2.2.2), from destination node, start to recall light tree along the opposite direction of business data flow, the wavelength span of these destination node business data flow processes dredged in record;

Step (2.2.3), according to these wavelength spans, obtain its corresponding physical link, wavelength span on these physical links is set, through the light path of these wavelength spans and the cost of subtree, is set to ∞;

With said method be provided with physical link with the tree of working separated after, utilize multicast service amount congestion relief algorithm to set up protection multicast forest for request, if protection multicast forest creates unsuccessfully, discharge so the resource taking in work multicast forest, algorithm is failed, end.

Step (3), protection WDM layer

Make T represent work tree, S represents the active section of processing, v _headand v _tailthe section head and the section coda wave meropodium point that represent respectively active section, V _mcrepresent MC wavelength node (the upper minute light quantity of light tree is less than the non-wavelength node arriving by wavelength transfer link of the maximum light splitting number of the node) set on T,

represent to can be used for providing from the MC of share protect wavelength node set:

Concrete steps are as follows:

Step (3.1), initialization

The link cost of all receiving links, logical links is set to ∞, and on the physical link of work tree process, all wavelength span costs are set to ∞;

Step (3.2), breadth First traversal light tree, obtain all waypoints and active section, and by traversal order, for each active section S provides protection, method is as follows:

Step (3.2.1),

by v _headadd to

in,

calculate the upper v of T _headall downstreams MC wavelength node, by they from

middle deletion;

The physical link set of step (3.2.2), evaluation work section process:

According to formula

remaining work is set and sets the wavelength span cost on the physical link of process not;

B wherein _t, b _w, b _p, b _newif represent respectively total bandwidth, bandwidth of operation, protection bandwidth and the newly assigned protection bandwidth of protection multicast forest these light path needs of the process number of this light path:

α _llit is the grade of logical links;

Step (3.2.3), calculating respectively

in all MC wavelength nodes to v _tailthe path of Least-cost, then from

in individual Least-cost path, select again the path of Least-cost; If find the ，Jiang Gai path, path of Least-cost to be denoted as P _min, corresponding in node be v _{exp and}; By P _minadd v to _{exp and}the set of protection section in, P _minthe use status indication of the wavelength span of process is " being used to protection "; By protection section through the use status indication of wavelength span for " being used to protection " after, the physical link of active section process is added to the array A of each wavelength span ₃in, if do not found, go to step (3.3);

If all working section is all protected successfully, algorithm successfully finishes; Otherwise, go to step (3.3);

Step (3.3), delete all protections sections in subtree, for the wavelength span in each protection section, by the physical link of active section process from A ₃middle deletion, if A after deleting ₃=Φ, is " not using " by the use status indication of this wavelength span, otherwise does not change use state, protect unsuccessfully, algorithm finishes.

Step (4), business are left away

When business is left away, need to discharge the resource that work multicast forest and protection multicast forest take, the method for releasing of the multicast forest reserves of wherein working is as follows:

Step (4.1), discharge the bandwidth taking in work multicast forest and each light path of protection multicast forest successively;

Step (4.2), for WDM layer protection is provided but its operating load lower than threshold value

light path, delete its protection road, be masked as " WDM layer is not protected " state, the service condition that each wavelength span of protection road process is set is " not using ";

Step (4.3), for the light path that dedicated bandwidth is 0, delete this light path: the service condition that each wavelength span of light path process is set is " do not use "; Light path source node place optical transmitter number adds one; Destination node place optical receiver number adds one;

Step (4.4), discharge the bandwidth taking on each light tree of work multicast forest and protection multicast forest successively;

Step (4.5), discharged after bandwidth, for the protection of WDM layer is provided but its operating load lower than threshold value light tree, delete all protections sections of this light tree, be masked as " WDM layer is not protected " state, service condition that each wavelength span of each protection section process is set is " use ";

Step (4.6), for dedicated bandwidth is 0 light tree, delete this light tree: the service condition that each wavelength span of light tree process is set is " not using "; Light path source node place optical transmitter number adds one; All destination nodes place optical receiver number adds one;

The method for releasing of the protection multicast forest reserves is as follows:

Each subtree of check protection multicast forest process successively, by the array A of this subtree ₁in the bandwidth corresponding to physical link of this vocational work multicast forest process deduct the bandwidth on demand of this business; If A ₁in bandwidth corresponding to certain physical link be 0, from A ₁this physical link of middle deletion, is re-set as A by the value of protection bandwidth ₁in the maximum of the corresponding bandwidth of each physical link;

If the load of certain subtree that the protection of WDM layer be provided is lower than threshold value

delete all protection sections in subtree; For the wavelength span in each protection section, by the physical link of active section process from A ₃middle deletion; If A after deleting ₃=Φ, is " not using " by the use status indication of this wavelength span, otherwise does not change use state.

Multi-layer protection method is shared in the multicast based on subtree in WDM optical-fiber network of the present invention; can expand traditional multicast and share the range of application of multi-layer protection method; when carrying out multilayer protection, consider a plurality of restraint conditions, provide the multicast under many strategies to share multi-layer protection method.

Accompanying drawing explanation

Fig. 1 be network configuration by multiple-layer overlapped the schematic diagram to two-layer evolution;

Fig. 2 is the schematic diagram of overlay model;

Fig. 3 is the schematic diagram of peer-to-peer model;

Fig. 4 is the physical topology schematic diagram of (physical topology N) for example;

Fig. 5 is the schematic diagram of the wavelength hierarchical diagram that physical topology N is corresponding (wavelength hierarchical diagram G);

Fig. 6 is the schematic diagram of network model;

Fig. 7 is the schematic diagram of network node;

Fig. 8 is wavelength hierarchical diagram;

Fig. 9 is basic multilayer auxiliary view;

Figure 10 has added to receive the multilayer auxiliary view after link;

Figure 11 is the schematic diagram of wavelength conversion after the first light splitting of node;

Figure 12 is the schematic diagram of light splitting after the first wavelength conversion of node;

Figure 13 is the schematic diagram of MC wavelength node;

Figure 14 is light tree segmentation one schematic diagram for example;

Figure 15 is light tree segmentation two schematic diagram for example;

Figure 16 is light tree segmentation three schematic diagram for example;

Figure 17 is light tree segmentation four schematic diagram for example;

Figure 18 is light tree segmentation five schematic diagram for example;

Figure 19 is the schematic diagram from share protect.

Figure 20 is the schematic diagram of the physical link separation of subtree.

Embodiment

Below in conjunction with accompanying drawing, the multicast based on subtree in WDM optical-fiber network of the present invention being shared to multi-layer protection method is described in further detail.

One, optical-fiber network basic platform

1 IP over WDM network overview and key technology thereof

1.1WDM technology

Growing continuously and fast of mobile service, 3G emerging service is saved up strength to start out, and the Internet services such as long-distance education, video conference, video request program, ecommerce flourish makes data traffic be explosive increase.The business demand of explosive increase has proposed new requirement to the capacity of communication system, function and performance.

The straightforward procedure that increases communication system bandwidth is to lay more optical fiber, costs dearly, and be subject to the restriction of the physical conditions such as natural environment, poor expandability but lay optical fiber.Another method is to adopt time division multiplexing (Time DivisionMultiplexing, TDM) technology, and it has improved transmission bit rate, but that the transmission capacity of simple optical fiber is still is limited, can not effectively utilize fiber bandwidth.Under this background, wavelength division multiplexing (Wavelength Division Multiplexing, WDM) technology is arisen at the historic moment.Wavelength division multiplexing is a kind of technology of transmitting a plurality of different wave length optical carriers in same optical fiber.At transmitting terminal, by multiplexer (Multiplexer), the optical carrier of different wave length is merged together, be put in an optical fiber and transmit; At receiving terminal, by demodulation multiplexer, the optical carrier of different wave length is separated, via optical receiver, be converted to original signal.In optical fiber, each wavelength independently transmits, and is independent of each other, and has improved greatly the transmission capacity of optical fiber, makes wavelength division multiplexing become best network capacity extension mode.Along with the reduction of optical device cost, and breakthrough and the maturation of the new technologies such as modulation technique, electronic dispersion compensation, super out-of-band FEC coding such as DQPSK, DP-QPSK, single wavelength 40Gbit/s, the systems such as transmission-link capacity 1.6Tbit/s are commercial.It is that 10.9Tbit/s (273 * 40Gbit/s) and total amount are the up-to-date world record of transmission capacity of 10.2Tbit/s (256 * 40Gbit/s) that Japan NEC and French Alcatel have been realized respectively total amount in 100km distance.

Traditional point-to-point wdm system structure adopts simple linear mode, with the dilatation of wavelength path mode, a large amount of original bandwidth can be provided, it need to introduce at network node place jumbo flexible optical node device just can be converted into the bandwidth that actual networking can flexible Application, realize WDM layer interconnected, construct optical transfer network (Optical Transport Network, OTN).This class optical node device mainly comprises reconfigurable light bifurcated multiplexer (Optical Add-Drop Multiplexer, OADM) and optical cross connect (Optical Cross Connect, OXC).By introduce OADM at nodes place, can insert in this locality the wavelength of Huo Xia road one group selection, flexibly upper and lower traffic carrying capacity.Along with the future development of WDM network towards mesh network, need to realize more coarsegrain at network hub node place, comprise wavelength, wavestrip, so that the processing light signal in optical fiber granularity, at hub node place, introduce OXC and necessitate.It mainly completes in functions such as wavelength, wavestrip and other connection of optical fiber level, bifurcated, protection and recoveries.

Press application type, OXC can be divided into optical fiber interconnection (Fiber Cross Connect, FXC), wavelength is selected interconnection (Wavelength Selective Cross Connect, WSXC) and wavelength exchange interconnection (Wavelength InterchangeCross Connect, WIXC).FXC exchanges on any output optical fibre all wavelengths on an input optical fibre is disposable; WSXC exchanges to a wavelength on an input optical fibre on the Same Wavelength on any output optical fibre; WIXC has wavelength conversion capability, a wavelength on an input optical fibre can be exchanged on any one wavelength on any output optical fibre.By implementation, OXC can be divided into the OXC (OEO-OXC, electric OXC) that adopts electric cross matrix and the OXC that adopts full optical cross-matrix (OOO-OXC, full light OXC).Electricity OXC is converted to the signal of telecommunication by opto-electronic conversion by light signal, carries out after interconnection processing, then is converted to light signal output.Full light OXC does not need to carry out opto-electronic conversion, and all intersections are all carried out at WDM layer.OADM and OXC only select the upper and lower road of the wavelength of local service, and other wavelength are expedite by network node, are referred to as bypass.OADM and OXC have reconfigurability flexibly, make network have wavelength routing capabilities, set up end to end wavelength path (light path, lightpath).Along with the continuous progress of OADM and OXC technology, WDM optical-fiber network develops towards complete mesh network from linear, ring network gradually.

Although OXC has networking capability flexibly, traditional OXC only has static configuration ability.In recent years, IP operation becomes the main business amount of network service gradually, uncertainty and Unpredictability due to IP operation, to the dynamic-configuration of the network bandwidth, require more and more urgent, network need to have the ability of dynamic-configuration, and traditional mode time and effort consuming by human configuration is easily made mistakes, and can not configure in time, its shortcoming manifests gradually.WDM optical-fiber network will adapt to the demand of new business; huge bandwidth capacity must can be made full use of; rational distribution service; as soon as possible for business connects; and provide protection and Restoration Mechanism; can also provide according to the demand of business the service of different service quality (Quality of Service, QoS) grade simultaneously.ASON (Automatic Switched Optical Network, ASON) ^[5,6]under such background, produce.It is the connection of managing network automatically, and this optical-fiber network with independent control plane is called ASON.

ASON can be found the variation of topology, resource and business automatically; Can be fast with set up dynamically light and be connected, realize the dynamic assignment of Internet resources; Introduce the mechanism of protection and restoration of basic mesh network, can adopt mode more flexibly protect and recover for business provides; How novel high speed can be provided and increase income business, for example, super band width service and nonstandard bandwidth business, bandwidth on-demand business, the configuration of dynamic virtual ring and end to end circuit configuration service, virtual optical network business etc.At present, the positive formulation work of carrying out ASON domain-specific standard of the International Standards Organization such as International Telecommunications Union (ITU-T), internet engineering task group (IETF), OIF Optical Internetworking Forum (OIF) and Guang Yu services interconnection alliance (ODSI).

1.2 network model

Along with business developments such as video conferences, the diversification gradually of Internet business, IP operation becomes main data traffic.WDM optical-fiber network, as leading transport network, provides huge transmission capacity.The fusion of IP and WDM becomes the trend of future network development.The interconnect model of transmission network is also developed to IP over WDM double-layer structure by traditional IP over ATM over SDH/SONET over WDM multiple-layer overlapped structure gradually, as shown in Figure 1.In the network configuration of multiple-layer overlapped; IP layer is used to provide business, and ATM layer guarantees for service connection provides service quality (Quality of Service, QoS); SDH/SONET layer utilizes its guard ring mechanism to protect and Restoration Mechanism for network provides, and WDM layer provides huge transmission bandwidth.But in multiple-layer overlapped network configuration, the cell mechanism of ATM has been brought larger overhead, has reduced bandwidth for transmission efficiency.Along with WDM optical-fiber network is developed to mesh network by looped network, although SDH/SONET protection mechanism is effective fast, its protection cost is higher, and the protection mechanism of SDH/SONET is no longer applicable.In order to reduce network operation cost, improve bandwidth resources utilance, ATM layer and SDH/SONET layer fade away, and transmission network finally develops into the two-tier network structure of IP over WDM, and IP operation is directly transmitted on WDM optical-fiber network.

In IP over WDM network, there are three kinds to control model, be respectively overlay model, peer-to-peer model and extended model.

(1) overlay model

Overlay model claims again client/server model, by ITU-T, is proposed.As shown in Figure 2, in this model, IP layer and WDM layer are separate, have control plane separately, move different Routing Protocols, the routing iinformation such as switching network topology not between Routing Protocol.IP layer and WDM layer are by user-network interface (User to Network Interface, UNI) link together, WDM layer consists of subnet, interconnected by Network-Network interface (Network to Network Interface, NNI) between each subnet.This model can be realized effective subnet and divide, and facilitates the control of each subnet and upgrading etc.IP layer can only be seen the light path of setting up between edge device in WDM layer, and in this model, the internal structure of WDM layer network is transparent to IP layer.IP layer to WDM layer proposition business transmission request, is responsible for the control of light path by UNI by WDM layer, the intelligence of network is reflected in WDM layer completely.It is separated with the control of IP layer that this model has been realized WDM layer to greatest extent.The shortcoming of overlay model is the light path of setting up between WDM layer edge device, be reflected as the logical links of IP layer, and the LSA of these links can cause very large network overhead.

(2) peer-to-peer model

Peer-to-peer model is proposed by IETF.As shown in Figure 3, in this model, IP layer and WDM layer are reciprocity, return unified control plane management.IETF is by this control plane called after GMPLS (GeneralizedMulti-protocol Label Switching, GMPLS).In peer-to-peer model, ip router and OXC are all called as LSR (Label Switching Router, LSR), they move identical route and signaling protocol, the routing iinformation such as exchanging chain line state to each other, IP layer can be seen the internal structure of WDM layer, and WDM layer is no longer transparent to IP layer.In peer-to-peer model, because IP layer and WDM layer are reciprocity, between each LSR, need to exchange a large amount of Link States and signaling control information, cause very large network overhead.The internal structure of WDM network, no longer to user transparent, is unfavorable for the stable of network, is also unfavorable for the division of subnet in WDM network; IP layer and WDM layer recovery mechanism, need unified coordination, controls complicated.

(3) extended model

In extended model, IP layer and WDM layer are separate, move independently Routing Protocol, but can exchange some reachability information by UNI between them.Be for example the OXC distributing IP address in WDM network, then by WDM layer Routing Protocol, offer IP layer and use, realize automatic pathfinding etc.The key issue of this model is how at UNI place, to exchange reachability information.

The present invention is mainly for peer-to-peer model.

1.3IP over WDM network key technology

In IP over WDM network, IP layer provides layer as business, and WDM layer is as transport layer, and its key issue is how to realize the seamless link of IP layer and WDM layer, and the GMPLS that IETF proposes provides a good solution thinking.In addition; the low speed service bandwidth granularity that IP receives is generally less than single wavelength capacities; so how effectively by service convergence, then carry these low speed business with WDM layer in IP over WDM, and be problem demanding prompt solution for business provides corresponding protection/Restoration Mechanism.In order to address the above problem, mainly proposed at present GMPLS, Traffic grooming, with the key technology such as the closely-related route of Traffic grooming and Wavelength Assignment and network survivability.

1.3.1GMPLS technology

GMPLS is the product that multi protocol label exchange (MPLS) develops to WDM layer, and it has realized the seamless fusion of IP layer and WDM optical-fiber network effectively.GMPLS has inherited nearly all excellent characteristic such as traffic engineering in MPLS, mpls protocol is expanded simultaneously.GMPLS is absorbed in control plane, supports the exchange of the multiple resources granularities such as packet switching, time-division switching, wavelength exchange and space switching (optical fiber exchange).GMPLS also supplements and revises original signaling and routing protocols in MPLS, and has designed brand-new LMP Link Manager Protocol (Link Management protocol, LMP).

(1) general multiple protocols label

GMPLS has defined five kinds of interface types, respectively: (a) packet switch capable (Packet Switch Capable, PSC): carry out packet switching, by identification boundaries of packets, according to the information of packet header, forward grouping.(b) second layer Fabric Interface (Layer2 Switch Capable, L2SC): carry out cell switching, the border of passing through by identification, forwards cell according to the information of cell head.(c) time division multiplexing capable (Time Division Multiplexing Capable, TDMC): carry out business forwarding according to TDM time slot.(d) lambda switch capable (Lambda Switch Capable, LSC): according to the optical wavelength of bearer service or optical band forwarding service.(e) fiber switch capable (Fiber Switch Capable, FSC): the physical location according to optical fiber in physical space forwards.GMPLS has done expansion to the label in MPLS, makes it to TDM time slot, wavelength, wavestrip, optical fiber etc., also can carry out mark.GMPLS unifies mark to IP exchanges data, TDM circuit switching and the exchange of WDM light.Packet switching label continues to adopt the label in MPLS, and circuit switching and light switch label have been re-started to definition, comprises request label, universal tag, suggestion label, sets label etc.Wherein, request label is for the foundation of label switched path (LabelSwitching Path, LSP); Universal tag is used for setting up after LSP, and indication is along the service conditions of LSP transmission; When suggestion label is used for configuring LSP, the time delay of avoiding reverse configuration to cause, Rapid Establishment light connects; Set label and for limiting downstream node, select the scope of label.

(2) common tags switching path

Exchange due to GMPLS support different resource granularity, when setting up LSP for fear of the waste of bandwidth resources, the LSP of inferior grade (PSC, L2SC, TDMC, LSC, FSC grade reduce successively) need to be nested in high-grade LSP, be called again LSP classification.LSP classification technique is realized by GMPLS labeled slots, after allowing the identical inferior grade LSP of entrance to converge, transparent in high-grade LSP, then distal portion from.Use the device interface types of every LSP starting and ending of LSP sizing specification identical.Same-interface refers to that the interface of certain grade can be used the multiplexing a plurality of LSP of certain technology.In MPLS, set up the unidirectional LSP that bidirectional LSP must be set up two opposite directions, its setup delay is long, signaling consumption is large.GMPLS improves it, can set up bidirectional LSP.While setting up bidirectional LSP, require the LSP of both direction to there is identical traffic engineering parameter, comprise resource requirement, protection/Restoration Mechanism etc.When GMPLS sets up bidirectional LSP, the path of uplink and downlink adopts same signaling message, and two LSP set up simultaneously, effectively reduces the time delay that LSP sets up, and has reduced signaling consumption.

(3) link management

In optical-fiber network, between two adjacent OXC, in the quantity of parallel optical fiber link and every optical fiber, multiplexing number of wavelengths is huge, if be respectively it, provide broadcast mechanism, in the time of can causing link maintenance and broadcast, the amount of information of transmission is very large, is unpractical for every optical fiber, each wavelength provide an IP address simultaneously.For this reason, GMPLS has adopted link bundling and has processed this problem without the mode of numbering link.If parallel link belongs to identical link group, these links can be bound so, form a bar bundle link.Identical link group refers to shared risk link group (Shared Risk LinkGroup, the SRLG) numbering that belongs to identical, identical link type of coding, identical protection/recovery type.Greatly reduce like this size of LSD, reduced the signaling consumption that broadcast brings.Without numbering link, refer to, adopt the mode of (router id, link number) two tuples to identify the address of link, with this, replace using the mode of IP address designation.GMPLS has formulated LMP Link Manager Protocol, is responsible for the functions such as control channel management between two adjacent nodes, link summary, link verification, fault management, and wherein link verification and fault management are optional.

(4) route and signaling protocol

When GMPLS adopts general multiple protocols label to set up LSP; need to consider the factor of bandwidth and protection/recovery capability; this requires node need to record link-state information; GMPLS expands to respectively RSVP-TE and CR-LDP by defined two the signaling protocol RSVP of MPLS traffic engineering and LDP for this reason, exchanges the parameter such as bandwidth, type, protection/Restoration Mechanism of LSP by signaling.Route Selection both can adopt explicit routing method, also can adopt the method for multi-hop.In addition, GMPLS also expands to respectively OSPF-TE and IS-IS-TE by the Routing Protocol OSPF and the IS-IS that control for traffic engineering in territory.The link management mechanism such as the binding of GMPLS link, LMP Link Manager Protocol have well reduced the expense that in route and signaling protocol, maintenance link state information is brought.

1.3.2 route and Wavelength Assignment

Given one group of connection, creates a light path and distributes the process of a wavelength to be called route and Wavelength Assignment (Route and Wavelength Assignment, RWA) for each connects.Connection request can be divided into two kinds: static connection request and dynamically connection request.For static traffic, the set of service connection request is given in advance, its target is to set up light path for these connection requests, and in global scope, minimize Internet resources used, such as number of wavelengths, fiber count etc., be the number of wavelengths of given fixed number, for connection request as much as possible is set up light path.Static routing and assignment of wavelength are called as static light path and set up (Static Lightpath Establishment, SLE) problem.For dynamic service, when connection request arrives, for it sets up light path, after business is left away, cancel light path.Its target is that the business for dynamically arriving is set up light path, and reduces blocking rate as much as possible, or maximizes the quantity of setting up light path in synchronization network.Dynamic routing and Wavelength Assignment are called as dynamic light path and set up (Dynamic Lightpath Establishment, DLE) problem.

At present route and assignment of wavelength are decomposed into Route Selection and two subproblems of Wavelength Assignment.First find a best route (for example shortest path), then check and whether have available wavelength for distributing.If because the successional constraint of wavelength does not have wavelength can distribute to this route, calculate so again the route of suboptimum, continue to repeat said process, until find a route that meets wavelength continuity constraint, otherwise block connection request.Before finding this route, method possibly iteration many times, for this problem, has proposed the concept of wavelength hierarchical diagram, route and Wavelength Assignment is converted to the problem of graph theory, solves the problem of Route Selection and Wavelength Assignment simultaneously.

Define grid topology is N (R, A, L, W), and wherein R is the set of lambda router node, and A is the set of access node, and L is nonoriented edge, and W is the wavelength available number in every physical link.Each access node is bundled on a lambda router and provides electro-optical conversion to support electricity exchange.Each limit is comprised of two reverse one-way optical fibers, on each optical fiber, can carry | W| wavelength channel.Definition wavelength layered graph model is G (V, E), and it is a directed graph.The process that obtains wavelength hierarchical diagram according to physical topology N is as follows: in N, each node i ∈ R copies in G | and W| time, these nodes are designated respectively if link l ∈ L connection route device i and router j, i wherein, j ∈ R, so for any w ∈ W,

with

by a directed edge

link together, wherein,

suppose that access node a ∈ A is connected on lambda router node r ∈ R.In G, for each access node a creates two nodes, one represents business generating portion (source), and another one represents business teste (object).These two nodes are designated respectively in G, add

to joint, account for

and

arrive

directed edge.Therefore the number of node in G | V|=|R| * | W|+2 * | A|; The number of directed edge | E|=2 * | L| * | W|.For example, the wavelength hierarchical diagram that physical topology shown in Fig. 4 is corresponding as shown in Figure 5.Wherein, the link between every lambda router is comprised of two reverse one-way optical fibers, and every optical fiber medium wave long number is 2.By wavelength hierarchical diagram, route just becomes relative simple with assignment of wavelength.As long as found the route that connects source and destination in certain wavelength plane, this route meets wavelength continuity constraint surely with regard to one.

1.3.3 Traffic grooming

WDM optical-fiber network provides huge transmission capacity, and the system of single wavelength capacities 40Gbit/s is commercial.But in actual applications,, the bandwidth on demand of each business is compared relatively low with single wavelength capacities, for example OC-12, OC-48, OC-192.Think that each low speed service request distributes a wavelength can cause a large amount of bandwidth waste.For each request creates a light path, also can increase the electric switching cost (for example needing to dispose more optical transceiver) of network, increase the cost of network.The most important thing is, the wavelength available number in real network is than few many of the low speed business number arriving.So Traffic grooming is the basic function that WDM optical-fiber network must have, to increase network throughput, improve wavelength resource utilance, reduce network cost.In WDM optical-fiber network, Traffic grooming is exactly the technology of transmitting in low speed service convergence to high speed light path, and its target is to minimize network cost or maximization network throughput.

In WDM optical-fiber network, Traffic grooming need to solve the problem of three aspects:: (1) sets up light path, and (2) distribute wavelength to meet wavelength continuity for light path, and (3) are route low speed business in logical topology.Whether given in advance according to business, Traffic grooming can be divided into two classes: static traffic amount is dredged with dynamic service amount and dredged.For static traffic amount, dredge, the method that these three problems can adopt shaping linear programming (Integer Linear Programming, ILP) to optimize solves together.But for catenet, the complexity of problem solving rises, and generally adopts heuritic approach to solve respectively three problems.In dynamic service amount is dredged, when service connection request arrives, first in logical topology, be that it finds route, if object is unreachable or existing light path on bandwidth be finished, create so new light path carrying new business and connect.

1.3.4 network survivability

After network survivability refers to and breaks down, network can provide the ability of persistent service.Development along with WDM technology, can multiplexing hundreds and thousands of wavelength in single fiber, the capacity of each wavelength also reaches tens hundreds of Gbit/s even, once there is network failure (as link failure etc.), the service failure that can cause the Tbit/s order of magnitude, causes and has a strong impact on.Therefore the survivability of WDM optical-fiber network becomes the major issue of people's growing interest.

WDM layer Survivability technology can be divided into two classes: protection (Protection) and recovery (Restoration).It is the reserved reserved resource of business in advance that protection refers to when business connects, once break down, business turns by reserved resource carries.Protection has a shorter protection switching time, but due to needs reserved reserved resource in advance, and while not breaking down, reserved resource is idle, so resource utilization is low.Recovery refers to not in advance as the reserved reserved resource of business, and when fault occurs, then according to network resource usage situation at that time, the mode of employing heavy-route, finds dynamically idling-resource and carry affected business.Recovery has higher resource utilization, but owing to being to find dynamically again available resources bearer service after fault occurs, so protection is long switching time, and heavier when offered load, while there is no enough available resources, can cause fault recovery failure.

Whether according to reserved resource, share, protection mechanism is divided into again two classes: privacy protection (Dedicated Protection) and share protect (Shared Protection).In privacy protection, for certain the work reserved reserved resource in road, to monopolize, other protection road can not re-use.In share protect, if two work Lu Buhui break down (if two work roads are physical link separation) simultaneously, they can share protect resource so.From the angle of resource utilization, share protect is higher than privacy protection resource utilization, and the traffic intensity of network is higher, and the advantage of share protect is more obvious.Protection switching time aspect, privacy protection is shorter than share protect.This is because in privacy protection, reserved resource is monopolized, can be pre-configured, once break down, just influenced business is switched in reserved resource; And in share protect, can not prejudge which service failure, and can not configure in advance, only have after fault occurs, then by the devices such as OXC on certain signaling mechanism configuration protection road, so its protection is longer switching time.

According to the granularity of protection, protection mechanism can be divided into path protection, link protection and sectionalised protection again.Path protection refer to for work road provide one to protect end to end road.Link protection refers to that once break down, the switching of business is responsible at faulty link two ends, without sourcesink node, participates in into protection road of each link calculation on work road.In sectionalised protection, the road segmentation of first working, then be that each section is calculated a protection road, first section of tail of section is responsible for fault recovery.Comparatively speaking, path protection has higher resource utilization, and the fault recovery of link protection participates in without sourcesink node, has that to protect faster switching time, sectionalised protection be to attempt at the two seeking balance.

A kind of as in Survivability technology, resist technology has protects switching time faster, can meet the requirement of a large amount of real time business, so the present invention relates generally to resist technology.

2 network models

Network model can be described as oriented connected graph G _p(V, L, W), as shown in Figure 6.V wherein, L, W represents respectively the wavelength set of node set, physical link set and every physical link of network, | V|, | L|, | W| represents respectively nodes, physical link number and every physical link medium wave long number of network.

2.1 network node

Network node is comprised of the OXC combining and ip router.Wherein, ip router is responsible for admission service request.OXC forms (as shown in Figure 7) by wavelength switching matrix, low speed traffic grooming matrix and one group of tunable transceiver.Wavelength in input optical fibre, after demultiplexing, can directly exchange to the corresponding wavelength of output optical fibre by wavelength switching matrix and get on, or exchanges to optical receiving set and be transformed into the signal of telecommunication and enter low speed and dredge matrix.Belong to local business and by low-speed service data flow port, transfer to ip router to process, non-local business is converted to light signal by optical transmitter, reenters wavelength switching matrix, and the respective wavelength that exchanges to corresponding optical fiber gets on.That is to say, in certain wavelength channel in input optical fibre, do not contain local service and can directly pass through wavelength switching matrix to output optical fibre, bypass; There is the wavelength channel of business up/down by processing under optical transceiver in electric territory.Each network node has been safeguarded overall link-state information, comprises the service condition of wavelength on each physical link, service condition of bandwidth etc. in each light path.

In addition, the constraints that the present invention considers mainly contains: the wavelength continuity constraint under the constraint of optical transceiver number, the conversion of sparse part wavelength, sparse part light splitting constraint etc.

(1) optical transceiver number

Each network node has been disposed optical transmitter and the optical receiver of some, and the present invention supposes that the optical transmitter of same node is identical with optical receiver number.

(2) wavelength conversion capability

According to node, whether there is wavelength conversion capability, node can be divided three classes: without wavelength conversion capability node, complete wavelength conversion capability node, part wavelength conversion capability node.

Without wavelength conversion capability, refer to, the wavelength channel in input optical fibre can only exchange to the wavelength channel of identical wavelength in output optical fibre by wavelength switching matrix and get on.

Wavelength conversion capability refers to completely, and the wavelength channel that the wavelength channel in input optical fibre can exchange to any wavelength in output optical fibre by wavelength switching matrix gets on.

Part wavelength conversion capability, the wavelength channel that the wavelength channel in input optical fibre can exchange to wavelength in certain limit adjacent with this wavelength in output optical fibre by wavelength switching matrix gets on.For example, certain node has part wavelength conversion capability, and its wavelength conversion range is 2, so wavelength X ₄can transform to wavelength X ₂, λ ₃, λ ₅and λ ₆get on.The wavelength conversion range with the node of part wavelength conversion capability may be not identical yet.

In the present invention, for convenience, the wavelength conversion capability of the unified conceptual description node with wavelength conversion range, is that wavelength conversion range is 0 by the node label without wavelength conversion capability, and the node wave length conversion range with complete wavelength conversion capability is | W|.

(3) light splitting ability

In WDM optical-fiber network, if will make node there is multicast capability, need to be at node deployment optical splitter.According to the power of light splitting ability, network node can be divided three classes: without light splitting ability MI (Multicast Incapable), complete light splitting ability, part light splitting ability.

Without light splitting ability, refer to, node can only be sent an input signal into an output port, if it is not multicast destination node, so can only be as the centre of multicast tree non-bifurcation node; If it is multicast destination node, it can only be as the leaf node of multicast tree so.

Light splitting ability refers to completely, and node can be sent into input signal any number of output ports.

Part light splitting ability refers to, node can be sent into input signal the output port of some.

Latter two node is referred to as MC (Multicast Capable) node, both can be used as the destination node of multicast tree, also can be used as the intermediate node of light tree.When as middle node of divergence, for the node of complete light splitting ability, its out-degree is restriction not; For the node of part light splitting ability, if it is not destination node, so its out-degree can not surpass its maximum can light splitting number; If simultaneously as destination node, need to separate a road light signal on this underground road, its out-degree can not surpass its maximum can subtract one by light splitting number.

Co-wavelength transfer capability is the same, for convenience, the present invention is unified can be made as 1 by light splitting number by maximum light splitting ability of can light splitting counting description node by the maximum without the node of light splitting ability, and has the degree that the node wave length conversion range of complete light splitting is node.

Existing wavelength conversion capability, has again the node of light splitting ability to have two kinds of node structures: (1) first carries out wavelength conversion, after carry out light splitting, (2) first carry out light splitting, after carry out wavelength conversion.The first node structure is simpler, and its two wavelength that separate must have identical wavelength, have certain limitation.The second node structure is more flexible, is the direction of development in the future, and its each light splitting wavelength out, can carry out wavelength conversion, therefore many to the quantitative requirement of wavelength shifter.In addition, from the angle of method, the method for design based on the first node structure is special circumstances (transforming to after light splitting on identical wavelength) of the second node structure in fact, so the present invention adopts the second node structure.

2.2 network link

Between two network nodes, by the contrary one-way optical fiber of a pair of transmission direction, connected.Article two, optical fiber has identical wavelength set, and number of wavelengths is | W|.Article two, optical fiber is physical link separation, and in the use of wavelength, and separate in the transmission of data, be independent of each other.

2.3 basic structure

For given physical topology G _p(V, L, W), according to following steps structure multilayer auxiliary view.

(1) by each node v _i∈ V, i=1,2 ..., | V|, copies | W| time, is labeled as respectively be called wavelength node.By the duplicated all wavelengths node of same node, there is identical ID, be its physical node ID.If from node v _ito node v _jthere is an oriented physical link l _ij, so for all w=1,2 ... | W|, from wavelength node

to wavelength node

increase a link

be called wavelength span, every wavelength span is corresponding to a wavelength in its place physical link.So just, constructed wavelength hierarchical diagram, the topology that the wavelength node that wherein each wavelength is corresponding and wavelength span form, is called wavelength plane.For example, according to the wavelength hierarchical diagram of physical topology structure in Fig. 6, (suppose that every physical link medium wave long number is 2) as shown in Figure 8.

(2) by each node v _i∈ V, i=1,2 ..., | V| copies one time, is designated v ' _i, be called logical node.Logical node is connected with winding-up for receiving, and can be understood as ip router node.If at WDM layer, there is one from node v _ito node v _jlight path, increase so one from node v ' _ito node v ' _jvirtual link, be called logical links (logical links is light path hereinafter), the bandwidth of logical links is the capacity (supposing that all light paths are all single wavelength channels) of a wavelength.The topology consisting of logical node and logical links is called logical topology.Logical topology and wavelength hierarchical diagram are combined and just formed basic multilayer auxiliary view.Or the topology of Fig. 6 of take is example, supposes with wavelength X ₂created one from node v ₂to node v ₄light path, light path is through intermediate node v ₃.By in wavelength hierarchical diagram arrive

and

arrive

wavelength span be labeled as and use, in logical topology, increase v ' ₂to v ' ₄logical links, the multilayer auxiliary view obtaining is as shown in Figure 9.

2.4 optical transceiver number constraints

When business is carried out to Traffic grooming, sometimes utilize existing logical links to can not find the route that can reach destination node, at this moment need newly-built light path.During each newly-built light path, light path source node need to consume an optical transmitter, and destination node consumes an optical receiver.Logical links, as the receiving node of business, need to record available light transmitter number and available light receiver number.As long as source, destination node have one not meet the demands, light path just can not be set up.For by the digitlization constraint of optical transceiver number, be converted into the content of graph theory, adopt the conceptual description optical transceiver number constraint of receiving link.For arbitrary node v _i∈ V, i=1,2 ..., | V|, increases v ' _iarrive

and

to v ' _ireceiving link.

Take Fig. 9 as example, suppose that each Nodes optical receiver number and optical transmitter number are 2, due to v ₂to v ₄a newly-built light path, so v ₂place's available light transmitter number subtracts one, v ₄place's available light receiver number subtracts one.The multilayer auxiliary view obtaining so as shown in figure 10, the other numeral of logical node wherein, expression available light transmitter number above, expression available light receiver number below.

2.5 wavelength conversion capability constraints

The present invention considers sparse part wavelength conversion capability constraint, and this constraint can solve by improving multilayer auxiliary view.

For arbitrary node v _i∈ V, its wavelength conversion range is r, increases so

w1=1,2 ..., | W| arrives w2=max{1, w1-r} ... w1-1, w1+1 ... min{|W|, the virtual link of w1+r}, is called wavelength transfer link.

Introduce after wavelength conversion capability, the structure of light path and light tree changes to some extent.

(1) light path

Light path in general sense, in order to meet wavelength continuity constraint, requires each wavelength span of light path process to have identical wavelength, and light path is comprised of one group of wavelength span with identical wavelength.When a newly-built light path, only need in certain wavelength plane, find the route of linked source, destination node.After considering wavelength conversion capability, each wavelength span of light path process can be used different wavelength, when a newly-built light path, is no longer just route in certain wavelength plane, but on multilayer auxiliary view route.The ordered set that now light path is comprised of wavelength span and wavelength transfer link.

(2) light tree

Introduce after wavelength conversion, each node on light tree is wavelength node, and father node may be wavelength span or wavelength transfer link to the link of child nodes.

3 link costs

The present invention adopts the working load of bandwidth in the balanced and light path of wavelength working load on physical link balanced, affected number of services when as far as possible reducing generation physical link fault.

In order better to realize load balancing, the present invention is that wavelength transfer link, logical links, receiving link, wavelength span are provided with different grades, is called α _wcl, α _ll, α _al, α _wll.Wavelength transfer link priority is the highest, is thereafter logical links, receiving link, wavelength span successively.Having a long way to go of the grade factor, for example be respectively 1,100,10000,1000000, the weights that its objective is each node in order to obtain according to Dijkstra shortest path algorithm analyze through wavelength conversion chains link way, logic chain way, receive number of links and wavelength span number.The minimum path of preferential choice for use wavelength span when this just impels routing, secondly selects to receive the less path of number of links, even with the less path of optical transceiver number, and to reduce the quantity of newly-built light path number, the last service condition of Compare Logic link again.

By change, receive the grade factor of link and wavelength span can reach different optimization aim.In upper example, main target is for being used minimum number of wavelengths.If will receive the larger grade factor of link setting, its optimization aim just becomes the minimum optical transceiver number of use so, and this is mainly applicable to the network that optical transceiver number is major constraints.

3.1 wavelength transfer links

Because wavelength transfer link is except the time delay that the conversion of introducing wavelength brings, the load of network is not exerted an influence, so the link cost of wavelength transfer link is suc as formula shown in 3.1.

W _wcl＝1×α _wcl (3.1)

Due on multilayer auxiliary view, while using the method processing node wavelength conversion capability of 2.5 joints introductions, there is the problem of continuous wavelength conversion.For example, if the excursion of certain node is 2, wavelength X so ₅can transform to wavelength X ₇but, wavelength X ₇can transform to λ ₉, by twice wavelength, change wavelength X ₅transformed to wavelength X ₉.But the wavelength variation range that the fact is this node is 2, wavelength X ₅can not transform to λ ₉.In the present invention, when moving dijkstra's algorithm pathfinding on multilayer auxiliary view, when certain wavelength node of expansion, if its previous dive node is wavelength node, and there is identical node ID with it, be that its previous dive link is wavelength transfer link, so in expansion during this node, the link cost of the wavelength transfer link in its neighbours limit is by ∞ calculating (the physical link cost of this wavelength transfer link be still 0 constant).With regard to having avoided, by continuous double bounce wavelength transfer link, cause wavelength conversion to exceed the problem of wavelength conversion range like this.In the path calculating like this, at each Nodes, before and after it, can only there is at most a wavelength transfer link.The dijkstra's algorithm of hereinafter using is all as above processed.

3.2 logical links

Each logical links is corresponding a light path of WDM layer all, and the capacity of logical links bandwidth is exactly the bandwidth capacity of light path.Article one, the loading condition of logical links can have multiple balancing method, such as the quantity of the LSP carrying on this logical links (label switched path), dedicated bandwidth accounts for the ratio of total bandwidth etc.Consider the bandwidth difference that different business is asked, simply with business number, be difficult to the loading condition of reflected optical path, so select dedicated bandwidth to account for the ratio of total bandwidth as the standard of a logical links loading condition of measurement.To account for the ratio of total bandwidth higher for dedicated bandwidth, and the load of this logical links is heavier, when routing, will avoid as much as possible this link, so will be the larger link cost of this link setting.In like manner, for dedicated bandwidth accounts for the lower less link cost of link setting of ratio of total bandwidth.

Make b _t, b _w, b _p, b _rthe total bandwidth, bandwidth of operation, protection bandwidth and the user's bandwidth on demand that represent respectively this logical links, the link cost of this logical links is suc as formula shown in 3.2 so.

$W_{\mathrm{ll}}=\left\{\begin{array}{cc}\&infin;& b_t-b_w-b_p<b_r\\ (1+\frac{b_w+b_p}{b_t})\&times;{\mathrm{\&alpha;}}_{\mathrm{ll}}& b_t-b_w-b_p\&GreaterEqual;b_r\end{array}\right.---\left(3.2\right)$

3.3 receive link

The link cost of receiving link is for reflecting the service condition of this Nodes optical transmitter and optical receiver.For certain node, when this node is during as the source node of new light path, consume optical transmitter of this Nodes; When this node is during as destination node, consume an optical receiver, so separate during the service condition of optical transmitter and optical receiver for certain node.

Make t _t, r _t, t _a, r _arepresent respectively the total optical transmitter number of this Nodes, total optical receiver number, available light transmitter number and available light receiver number, the link cost from logical node corresponding to this node to the receiving link of the corresponding all wavelengths node of this node is suc as formula shown in 3.3 so.

$W_{\mathrm{al}}=\left\{\begin{array}{cc}\&infin;& t_a=t_t\\ (1+\frac{t_t-t_a}{t_t})\&times;{\mathrm{\&alpha;}}_{\mathrm{al}}& t_a<t_t\end{array}\right.---\left(3.3\right)$

The corresponding all wavelengths node of this node to the link cost of the receiving link of its logical node suc as formula shown in 3.4.

$W_{\mathrm{al}}=\left\{\begin{array}{cc}\&infin;& r_a=r_t\\ (1+\frac{r_t-r_a}{r_t})\&times;{\mathrm{\&alpha;}}_{\mathrm{al}}& r_a<r_t\end{array}\right.---(3.4)$

3.4 wavelength span

The link cost of wavelength span is for reflecting the loading condition of physical link under this wavelength span.The loading condition of physical link can be with weighing by the ratio that number of wavelengths accounts for total number of wavelengths.Wavelength span has four kinds of use states: do not use, be used to build light path, be used to build light tree, be used to protection.

Make w _w, w _poperating wave long number and protection number of wavelengths in physical link under this wavelength span respectively, if this wavelength span is used, its link cost is ∞ so, otherwise its link cost is suc as formula shown in 3.5.

$W_{\mathrm{wll}}=\left\{\begin{array}{cc}\&infin;& w_w+w_p=\left|W\right|\\ (1+\frac{w_w-w_p}{\left|W\right|})\&times;{\mathrm{\&alpha;}}_{\mathrm{wll}}& w_w+w_p<\left|W\right|\end{array}\right.---(3.5)$

Multi-layer Protection Algorithm is shared in 4 multicasts based on subtree

4.1 reserved resource sharing policies

Different according to shared granularity, reserved resource sharing policy can be divided into subtree reserved resource sharing policy, light path reserved resource sharing policy and wavelength span reserved resource sharing policy.

4.1.1 subtree reserved resource sharing policy

If two protection multicast forests have been used identical subtree, and their work multicast forest is physical link separation, and in this subtree, they can share protect bandwidth so.

Make R _tfor the request set of protection multicast tree through subtree t, E _rfor the set of physical link of the work multicast tree process of request r, protection multicast tree through the work multicast tree of t the set of physical link of process

for work multicast tree is through physical link e, protection multicast tree is through the request set of t, for any e ∈ A ₁,

b _rbandwidth on demand for business r.

Whenever being a new request foundation protection multicast forest; and during this protection multicast forest process t; so first, each light path and the subtree of its work multicast forest process are listed; and then list successively the physical link of each subtree and light path process; remove the physical link of repetition; every physical link only retains one, forms array A ₂.

For e ∈ A arbitrarily ₂if,

add e to A so ₁in, while military order

bandwidth on demand for new business; If e ∈ is A ₁, order

this subtree needs newly assigned reserved resource bandwidth

if there is no enough idle bandwidths on l, t is unavailable so.

4.1.2 light path reserved resource sharing policy

If two protection multicast forests have been used identical light path, and their work multicast forest is physical link separation, and in this light path, they can share protect bandwidth so.

Make R _lfor the request set of protection multicast tree through light path l; E _rthe set of physical link for the work multicast tree process of request r; Protection multicast tree through the work multicast tree of l the set of physical link of process

for work multicast tree is through physical link e, protection multicast tree is through the request set of l; For any e ∈ A ₁, b _rbandwidth on demand for business r.

Whenever being that protection multicast forest is set up in a new request, and this protection multicast forest is during through l, so first each light path and the subtree of its work multicast forest process is listed, and then is listed successively the physical link of each subtree and light path process.Between these physical links, may have repetition, remove the physical link of repetition, every physical link only retains one, forms array A ₂.

For e ∈ A arbitrarily ₂if,

add e to A so ₁in, while military order

bandwidth on demand for new business; If e ∈ is A ₁, order

this light path needs new reserved resource bandwidth of distributing if there is no enough idle bandwidths on l, l is unavailable so.

4.1.3 wavelength span reserved resource sharing policy

Wavelength span reserved resource is shared and to be referred to when multicast shared segment protect, if two protection sections through identical wavelength spans, and its corresponding active section is physical link separation, they can share this wavelength span of use so.

The wavelength span l of every protected section of use, has recorded all protection sections through the physical link of the active section process of the request of l, is designated as array A ₃.When being an active section searching protection section, if the physical link of this active section process is not all at array A corresponding to this wavelength span l ₃in, its protection section can be shared this wavelength span so.

4.2 cost

When setting up work multicast forest, owing to not relating to the sharing problem of reserved resource, so arrange when the setting of its subtree, light path cost and privacy protection identical.But when setting up protection multicast forest, the setting of subtree, light path and wavelength span cost and distinguishing to some extent while setting up work multicast forest.

4.2.1 subtree cost

In reserved resource, share in situation, while setting up protection multicast forest for service request, affect the factor of a stalk tree cost except the load of this subtree, protect in addition multicast forest to need newly assigned protection bandwidth number through this subtree.

Make b _t, b _w, b _p, b _newif represent respectively, total bandwidth, bandwidth of operation, protection bandwidth and the protection multicast forest of this subtree are through the newly assigned protection bandwidth of these subtree needs number, and the cost of this subtree is so

$W_{\mathrm{st}}=\left\{\begin{array}{cc}\&infin;& r_{\mathrm{groo}\min g}<Q_{\mathrm{groo}\min g}\\ \&infin;& b_t-b_w-b_p<b_{\mathrm{new}}\\ \frac{b_w+b_p}{b_t}& b_t-b_w-b_p\&GreaterEqual;b_{\mathrm{new}}\end{array}\right.---\left(4.1\right)$

4.2.2 light path cost

Make b _t, b _w, b _p, b _newif represent respectively, total bandwidth, bandwidth of operation, protection bandwidth and the protection multicast forest of this light path are through the newly assigned protection bandwidth of these light path needs number, and the link cost of this light path is so

$W_{\mathrm{ll}}=\left\{\begin{array}{cc}\&infin;& b_t-b_w-b_p<b_{\mathrm{new}}\\ \left(\frac{b_{\mathrm{new}}}{b_t}\right)(1+\frac{b_w+b_p}{b_t})\&times;{\mathrm{\&alpha;}}_{\mathrm{ll}}& b_t-b_w-b_p\&GreaterEqual;b_{\mathrm{new}}\end{array}\right.---\left(4.2\right)$

4.2.3 wavelength span cost

When using MSSP algorithm to calculate the protection of WDM layer, if this wavelength span is not used or use state for " being used to protection " and can share this wavelength time, the link cost of wavelength span arranges by formula 3.5, otherwise is set to ∞.

4.3 share segmentation method

Known network physical topology G _p(V, L, W) and multicast route requests r (v _s, D), v wherein _s, D ∈ V, v _sbe source node, D is destination node collection, for a light tree set that meets multiple constraint in 2.1 joints is set up in request.

Described in 2.1 joints, for the network node simultaneously with wavelength conversion ability and light splitting ability, adopt the method for wavelength conversion after first light splitting, after this and first wavelength conversion, the method for light splitting is reflected on multilayer auxiliary view and has a great difference, as shown in Figure 11, Figure 12.In figure, be with arrow solid line to represent the upper business datum flow path direction of light tree, without arrow solid line, represent link, input wavelength shown in Figure 11 is λ ₂, two wavelength after light splitting are transformed into respectively λ ₁and λ ₃; Input wavelength shown in Figure 12 is also λ ₂, after wavelength conversion, become λ ₃, and then carrying out light splitting, two wavelength after light splitting are λ ₃.

(1) minute light quantity of wavelength node

The present invention defines light and sets minute light quantity that the number of times of wavelength node light splitting is this wavelength node.When a wavelength node is not destination node, minute light quantity of this wavelength node refers to the number of its child nodes; When this wavelength node is destination node, due to as destination node, need the copy of a business data flow, so its minute light quantity refers to that its child nodes number adds one.

(2) MC wavelength node

MC wavelength node refers to that the upper minute light quantity of light tree is less than the non-wavelength node arriving by wavelength transfer link of the maximum light splitting number of node.

Figure 13 has shown part multilayer auxiliary view, wherein has arrow solid line to represent the direction of Business Stream on multicast tree, v ₁have wavelength conversion ability, maximum light splitting number is 4.In figure, due to when the practical operation, light signal is at v ₁locate first light splitting three times, divide and be clipped to v ₂, v ₃, v ₄, then arrive v ₂and v ₄light signal again wavelength conversion to λ ₁so,

minute light quantity be 3, rather than 2.In figure due to

minute light quantity be 3 to be less than its maximum light splitting number 4, so it is MC wavelength node.If node v ₁while or the destination node of multicast service, so light splitting quantitative change be 4, light splitting again, is no longer MC wavelength node.In figure

because its previous dive is wavelength transfer link, so it is not MC wavelength node.

It is waypoint that the present invention's degree of weighing up is not less than 2 MC wavelength node, and the part between two waypoints and between segmented node and leaf node is called active section, and Figure 14 has provided several forms of active section to Figure 18.In Figure 14

in Figure 15

in Figure 16

in Figure 17

in Figure 18

deng being all called as active section.

In Figure 18, because node is all taked the strategy of wavelength conversion after first light splitting, so node v ₁after wanting first light splitting, wavelength is transformed into λ ₁, because

its previous dive is wavelength transfer link, so it is not MC wavelength node, so

the section of being not.

When protecting, claimed section is that physical link is separated with light tree.If only, from the angle of protection, can provide one to put corresponding logical node from section Mintrop wave meropodium and put the light path of corresponding logical node to section coda wave meropodium for active section.Need to consume respectively an optical transmitter and optical receiver at section head and a section tail node place like this.Due to section, head has been used optical transmitter, and it has just possessed the ability of receiving breakout service so, and light tree source node is no longer unique node with the ability of receiving breakout service, can cause like this dredging with light tree allocated bandwidth chaotic.So the present invention does not carry out light path protection to section.

During due to active section fault, discharged a minute light quantity, so do not need to consider minute luminosity of section Mintrop wave meropodium point when creating protection section.

4.4 from share protect

From share protect, refer to for certain active section, can utilize the active section on light tree to protect.For example, in Figure 19, for section v ₁→ v ₂→ v ₃, can be newly-built one from v ₅to v ₃path, then utilize v ₁→ v ₄→ v ₅→ v ₃as v ₁→ v ₂→ v ₃protection section, the present invention claims v ₁→ v ₄→ v ₅for front protection section, v ₅→ v ₃for rear protection section.In like manner can utilize v ₁→ v ₂→ v ₃→ v ₅as v ₁→ v ₄→ v ₅protection section.The wavelength path of two sections of tail node of connection of finding is that physical link is separated with Guang Shu.

After share protect requires, the section coda wave meropodium point of protection section is MC node.For example, in Figure 19, if v ₅minute luminosity be 2, so just can not be again with a section v ₁→ v ₂→ v ₃for providing, other section protected.

Two, multi-layer protection method is shared in the clean culture based on load balancing in optical-fiber network of the present invention, comprises the steps:

Step (1), set up work multicast forest

Setting up work multicast forest is exactly for multicast request, to carry out the process of Traffic grooming in fact, adopts multicast service amount congestion relief algorithm for asking to set up work multicast forest; If multicast service amount congestion relief algorithm is dredged unsuccessfully, algorithm finishes so;

Step (2), foundation protection multicast forest

It is that physical link is separated that protection multicast forest requires with work multicast forest.

The physical link of step (2.1) light path is separated

Wavelength span on each physical link of light path process is set, through the light path of these wavelength spans and the cost of subtree, is set to ∞;

The physical link of step (2.2) subtree is separated

For request, setting up work multicast forest, when using a certain stalk tree to dredge, if dredge availability factor, not 100%, the business of carrying on some link in subtree so and this request are irrelevant, that is to say when these link occurs fault, do not affect the operation of this business; So, when the physical link that subtree is set is separated, be not wavelength span on the physical link of simple subtree process, through the light path of these wavelength spans and the cost of subtree, be set to ∞; The step that physical link separation is set is as follows:

Step (2.2.1) arranges the cost of light tree and light path by formula 4.1,4.2, search the destination node of dredging by this subtree;

Step (2.2.2) starts to recall light tree along the opposite direction of business data flow from destination node, and the wavelength span of these destination node business data flow processes dredged in record;

Step (2.2.3) obtains its corresponding physical link according to these wavelength spans, and the wavelength span, the process light path of these wavelength spans and the cost of subtree that arrange on these physical links are set to ∞;

For example, in Figure 20, the destination node set { v of light tree ₄, v ₅, v ₆, v ₇, v ₈, suppose destination node v in request ₆, v ₇and v ₈use this light tree to dredge, work as so v ₁→ v ₂, v ₂→ v ₃and v ₃→ v ₄physical link while breaking down, traffic affecting normal transmission not, so when the physical link that this subtree is set is separated, only need to arrange v ₁→ v ₈, v ₁→ v ₃, v ₃→ v ₆and v ₃→ v ₇this four edges physical link is separated.

By the method for this set subtree physical link separation, can effectively reduce number separated due to physical link while creating protection multicast forest and wavelength span, light path and subtree that can not be used, reduce and dredge probability of failure;

After dredging successfully with multicast service amount congestion relief algorithm; when distributing bandwidth resources for protection multicast forest; to upgrade respectively the bandwidth resources in subtree and light path according to the description in 4.1.1 and 4.1.2 joint, the set of the physical link of work multicast forest process is updated to the array A on the subtree He Zi road that protection multicast forest uses ₁in.

With said method be provided with physical link with the tree of working separated after, utilize SMTG algorithm to set up protection multicast forest for request, if protection multicast forest creates unsuccessfully, discharge so the resource taking in work multicast forest, algorithm is failed, end.

Step (3), protection WDM layer

Make T represent work tree, S represents the active section of processing, v _headand v _tailthe section head and the section coda wave meropodium point that represent respectively active section, V _mcrepresent MC wavelength node (the upper minute light quantity of light tree is less than the non-wavelength node arriving by wavelength transfer link of the maximum light splitting number of the node) set on T,

represent to can be used for providing from the MC of share protect wavelength node set:

Concrete steps are as follows:

Step (3.1), initialization.

The link cost of all receiving links, logical links is set to ∞, and on the physical link of work tree process, all wavelength span costs are set to ∞;

Step (3.2), breadth First traversal light tree, obtain all waypoints and active section.By traversal order, for each active section S provides protection, method is as follows:

Step (3.2.1)

by v _headadd to

in,

calculate the upper v of T _headall downstreams MC wavelength node, by they from

middle deletion;

The physical link set of step (3.2.2) evaluation work section process, and remaining work is set sets the wavelength span cost on the physical link of process not by describing in 4.2.2 joint;

Step (3.2.3) is calculated respectively

in all MC wavelength nodes to v _tailthe path of Least-cost, then from

in individual Least-cost path, select again the path of Least-cost; If find the ，Jiang Gai path, path of Least-cost to be denoted as P _min, corresponding

in node be v _{exp and}; By P _minadd v to _{exp and}the set of protection section in, P _minthe use status indication of the wavelength span of process is " being used to protection "; By protection section through the use status indication of wavelength span for " being used to protection " after, the physical link of active section process is added to the array A of each wavelength span ₃in, if do not found, go to step (3.3);

If all working section is all protected successfully, algorithm successfully finishes; Otherwise, go to step (3.3);

Step (3.3), delete all protections sections in subtree, for the wavelength span in each protection section, by the physical link of active section process from A ₃middle deletion, if A after deleting ₃=Φ, is " not using " by the use status indication of this wavelength span, otherwise does not change use state, protect unsuccessfully, algorithm finishes.

Step (4), business are left away

When business is left away, need to discharge the resource that work multicast forest and protection multicast forest take, the method for releasing of the multicast forest reserves of wherein working is as follows:

Step (4.1), discharge the bandwidth taking in work multicast forest and each light path of protection multicast forest successively;

Step (4.2), for WDM layer protection is provided but its operating load lower than threshold value

light path, delete its protection road, be masked as " WDM layer is not protected " state, the service condition that each wavelength span of protection road process is set is " not using ";

Step (4.3), for the light path that dedicated bandwidth is 0, delete this light path: the service condition that each wavelength span of light path process is set is " do not use "; Light path source node place optical transmitter number adds one; Destination node place optical receiver number adds one;

Step (4.4), discharge the bandwidth taking on each light tree of work multicast forest and protection multicast forest successively;

Step (4.5), discharged after bandwidth, for the protection of WDM layer is provided but its operating load lower than threshold value

light tree, delete all protections sections of this light tree, be masked as " WDM layer is not protected " state, service condition that each wavelength span of each protection section process is set is " use ";

Step (4.6), for dedicated bandwidth is 0 light tree, delete this light tree: the service condition that each wavelength span of light tree process is set is " not using "; Light path source node place optical transmitter number adds one; All destination nodes place optical receiver number adds one;

The method for releasing of the protection multicast forest reserves is as follows:

Each subtree of check protection multicast forest process successively, by the array A of this subtree ₁in the bandwidth corresponding to physical link of this vocational work multicast forest process deduct the bandwidth on demand of this business.If A ₁in bandwidth corresponding to certain physical link be 0, from A ₁this physical link of middle deletion, is re-set as A by the value of protection bandwidth ₁in the maximum of the corresponding bandwidth of each physical link;

If the load of certain subtree that the protection of WDM layer be provided is lower than threshold value

delete all protection sections in subtree; For the wavelength span in each protection section, by the physical link of active section process from A ₃middle deletion; If A after deleting ₃=Φ, is " not using " by the use status indication of this wavelength span, otherwise does not change use state.

Claims (1)

1. a multi-layer protection method is shared in the multicast based on subtree in WDM optical-fiber network, it is characterized in that: comprise the steps:

Step (1), set up work multicast forest

Adopt multicast service amount congestion relief algorithm for asking to set up work multicast forest; If multicast service amount congestion relief algorithm is dredged unsuccessfully, algorithm finishes so;

Step (2), foundation protection multicast forest

The physical link of step (2.1), light path is separated

Wavelength span on each physical link of light path process is set, through the light path of these wavelength spans and the cost of subtree, is set to ∞;

The physical link of step (2.2), subtree is separated

Step (2.2.1), by formula $W_{\mathrm{st}}=\left\{\begin{array}{cc}\&infin;& r_{\mathrm{groo}\min g}<Q_{\mathrm{groo}\min g}\\ \&infin;& b_t-b_w-b_p<b_{\mathrm{new}}\\ \frac{b_w+b_p}{b_t}& b_t-b_w-b_p\&GreaterEqual;b_{\mathrm{new}}\end{array}\right.$ The cost W of light tree is set _st,

By formula $W_{\mathrm{ll}}=\left\{\begin{array}{cc}\&infin;& b_t-b_w-b_p<b_{\mathrm{new}}\\ \left(\frac{b_{\mathrm{new}}}{b_t}\right)(1+\frac{b_w+b_p}{b_t})\&times;{\mathrm{\&alpha;}}_{\mathrm{ll}}& b_t-b_w-b_p\&GreaterEqual;b_{\mathrm{new}}\end{array}\right.$ The cost W of light path is set _ll, search the destination node of dredging by this subtree;

Wherein: b _t, b _w, b _p, b _newif represent respectively, total bandwidth, bandwidth of operation, protection bandwidth and the protection multicast forest of this light path are through the newly assigned protection bandwidth of these light path needs number, α _llfor the grade factor of logical links, r _groomingfor light tree, dredge node availability factor, Q _groomingfor what arrange, dredge node availability factor threshold value;

Step (2.2.2), from destination node, start to recall light tree along the opposite direction of business data flow, the wavelength span of these destination node business data flow processes dredged in record;

Step (2.2.3), according to these wavelength spans, obtain its corresponding physical link, the wavelength span on these physical links is set, through the light path of these wavelength spans and the cost of subtree, be set to ∞;

With said method be provided with physical link with the tree of working separated after, utilize multicast service amount congestion relief algorithm to set up protection multicast forest for request, if protection multicast forest creates unsuccessfully, discharge so the resource taking in work multicast forest, algorithm is failed, end;

Step (3), protection WDM layer

Make T represent work tree, S represents the active section of processing, v _headand v _tailthe section head and the section coda wave meropodium point that represent respectively active section, V _mcrepresent the MC wavelength node set on T, described MC wavelength node is the non-wavelength node arriving by wavelength transfer link that the upper minute light quantity of light tree is less than the maximum light splitting number of node; Described wavelength node is by each node v _i∈ V, i=1,2 ..., | V|, copies | W| time, is labeled as respectively

wherein, V represents the node set of network, | V| represents the nodes of network;

represent to can be used for providing from the MC of share protect wavelength node set:

Concrete steps are as follows:

Step (3.1), initialization

The link cost of all receiving links, logical links is set to ∞, and on the physical link of work tree process, all wavelength span costs are set to ∞;

Step (3.2), breadth First traversal light tree, obtain all waypoints and active section, and by traversal order, for each active section S provides protection, method is as follows:

Step (3.2.1),

by v _headadd to

in,

calculate the upper v of T _headall downstreams MC wavelength node, by they from

middle deletion;

The physical link set of step (3.2.2), evaluation work section process:

According to formula $W_{\mathrm{ll}}=\left\{\begin{array}{cc}\&infin;& b_t-b_w-b_p<b_{\mathrm{new}}\\ \left(\frac{b_{\mathrm{new}}}{b_t}\right)(1+\frac{b_w+b_p}{b_t})\&times;{\mathrm{\&alpha;}}_{\mathrm{ll}}& b_t-b_w-b_p\&GreaterEqual;b_{\mathrm{new}}\end{array}\right.$ Remaining work is set and sets the wavelength span cost on the physical link of process not;

B wherein _t, b _w, b _p, b _newif represent respectively total bandwidth, bandwidth of operation, protection bandwidth and the newly assigned protection bandwidth of protection multicast forest these light path needs of the process number of this light path:

α _llit is the grade factor of logical links;

Step (3.2.3), calculating respectively in all MC wavelength nodes to v _tailthe path of Least-cost, then from

in individual Least-cost path, select again the path of Least-cost; If find the ，Jiang Gai path, path of Least-cost to be denoted as P _min, corresponding

in node be v _expand; By P _minadd v to _expandthe set of protection section in, P _minthe use status indication of the wavelength span of process is " being used to protection "; By protection section through the use status indication of wavelength span for " being used to protection " after, the physical link of active section process is added to the array A of each wavelength span ₃in, if do not found, go to step (3.3);

If all working section is all protected successfully, algorithm successfully finishes; Otherwise, go to step (3.3);

Step (3.3), delete all protections sections in subtree, for the wavelength span in each protection section, by the physical link of active section process from A ₃middle deletion, if A after deleting ₃=Φ, is " not using " by the use status indication of this wavelength span, otherwise does not change use state, protect unsuccessfully, algorithm finishes;

Step (4), business are left away

When business is left away, need to discharge the resource that work multicast forest and protection multicast forest take, the method for releasing of the multicast forest reserves of wherein working is as follows:

Step (4.1), discharge the bandwidth taking in work multicast forest and each light path of protection multicast forest successively;

Step (4.2), for WDM layer protection is provided but its operating load lower than threshold value

light path, delete its protection road, be masked as " WDM layer is not protected " state, the service condition that each wavelength span of protection road process is set is " not using ";

Step (4.3), for the light path that dedicated bandwidth is 0, delete this light path: the service condition that each wavelength span of light path process is set is " do not use "; Light path source node place optical transmitter number adds one; Destination node place optical receiver number adds one;

Step (4.4), discharge the bandwidth taking on each light tree of work multicast forest and protection multicast forest successively;

Step (4.5), discharged after bandwidth, for the protection of WDM layer is provided but its operating load lower than threshold value

light tree, delete all protections sections of this light tree, be masked as " WDM layer is not protected " state, service condition that each wavelength span of each protection section process is set is " use ";

Step (4.6), for dedicated bandwidth is 0 light tree, delete this light tree: the service condition that each wavelength span of light tree process is set is " not using "; Light path source node place optical transmitter number adds one; All destination nodes place optical receiver number adds one;

The method for releasing of the protection multicast forest reserves is as follows:

Each subtree of check protection multicast forest process successively, by the array A of this subtree ₁in the bandwidth corresponding to physical link of this vocational work multicast forest process deduct the bandwidth on demand of this business; If A ₁in bandwidth corresponding to certain physical link be 0, from A ₁this physical link of middle deletion, is re-set as A by the value of protection bandwidth ₁in the maximum of the corresponding bandwidth of each physical link;

If the load of certain subtree that the protection of WDM layer be provided is lower than threshold value

delete all protection sections in subtree; For the wavelength span in each protection section, by the physical link of active section process from A ₃middle deletion; If A after deleting ₃=Φ, is " not using " by the use status indication of this wavelength span, otherwise does not change use state.

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