CN103023781B - Shortest path tree and spanning tree combined energy-saving routing method - Google Patents

Abstract

The invention discloses a shortest path tree and spanning tree combined routing method and belongs to the technical field of network topology. The method is characterized in that on the basis of a standard link state routing protocol, a dormant state is added to each link which is connected with a router node in a network, a shared spanning tree is selected on a given network topology, links on the spanning tree are in a working state all the time so as to guarantee network connectivity, other links which are not on the spanning tree enter into dormant states if no flow passes, each router stores a shortest path routing list of the whole network path and a routing list of a corresponding spanning tree, as for a data packet, an ingress router determines that the data packet uses a path therein according to current link loads, a label identification is added, and a non ingress router selects a corresponding routing list according to a label to perform forwarding.

Description

The energy-saving routing method that shortest path tree is combined with spanning tree

Technical field

GreenNet

Background technology

GreenNet is an important directions of current network research, and the huge energy consumption problem of the Internet and inefficient energy use problem day by day to highlight.In order to more effectively utilize the energy, reduce energy dissipation, the research utilizing link dormant mechanism to realize network energy-saving is obtaining academia and industrial quarters is more and more paid close attention to.In general Internet Service Provider (ISP) network; in order to tackle flow summit and potential link failure; the networking and upgrading period; Virtual network operator usually can be disposed redundant link and increase redundant link bandwidth; and offered load is not high time most in actual commodity network; cause link average utilization on the low side, and router power consumption is compared full load running status and be there is no reduction.These factors all can cause the energy dissipation problem in network.

Link-state routing protocol is now conventional intra-area routes agreement, the path that the router of this agreement calculates is shortest path, owing to not considering the factors such as energy consumption at the beginning of this Protocol Design, the utilance that result in ISP network uplink is low, the problem of a large amount of energy dissipations.The object of the invention is to improve traditional standard Link State route, adopt the power-saving mechanism that spanning tree (ST:spanningtree) and shortest path tree (SPT:shortest path tree) combine, flow is gathered on the least possible link, and all the other links enter idle state to reach energy-conservation.

Summary of the invention

The object of the invention is to two kinds of different shortest path paths and the novel energy-conservation line state method for routing of spanning tree path configuration one, flow is gathered in spanning tree, more multilink is made to enter resting state, while realizing energy-conservation object, improve average link utilization, reduce energy dissipation.

The invention is characterized in:

1. network topology realizes successively according to the following steps:

Step (1), network topology initialization: on the basis of standard Link State Routing Protocol, increases resting state on every bar link that wherein each router node connects;

Step (2), each router node periodically detects the loading condition of all direct connected links, use the LSA of open type shortest path priority protocol OSPF mechanism LSA itself that link loading information is flooded in network topology together with link-state information, make each router node in described network topology all have identical network topological information and link loading information;

Step (3), each router node calculates shortest path and the spanning tree path of oneself other arbitrary router node on network topology according to the result obtained from step (2), generate routing table, and the result of calculation of all-router node is consistent;

Step (4), each router node in described network topology is according to the situation of the path uplink load of data flow process, be that each data flow selects a suitable path by destination address, select corresponding routing table, and selection result is added to the head of data message as label, forward by " destination address+label " again, determine route next jump in the routing table according to label;

Step (5), when downstream router node receive forwarded by upstream router with the message of label after, select down hop according to label, forward by the form of " destination address+label ";

Step (6), after core router node receives a message, check the link forwarding end, if it is normal to forward Duan Duanlu, then normally forward by label, if when finding that the link of forwarding end is in resting state, need this dormancy link wakeup, be that the label of spanning tree forwards again by the tag modification of this datagram, until arrive object router.

2. the energy-saving routing method that is combined with spanning tree of shortest path tree according to claim 1, it is characterized in that, described spanning tree constructs one again for the actual online subgraph adopted, each router node on it is on some links of described spanning tree, also to comprise the limit of minimum number, lose efficacy to prevent single-link.

The thinking of method proposed by the invention is: on the basis of standard Link State Routing Protocol, and every bar link that routers node connects increases resting state.In given network topology formulate a connected subgraph, the link on connected subgraph is in running order all the time, if other nodes outside connected subgraph continue for some time do not have flow through; enter resting state.Flow, by building a spanning tree on connected subgraph, collecting in spanning tree, making the link entering dormancy more mainly with reaching energy-conservation effect by router.

The advantage of method proposed by the invention is:

1. adopt distributed algorithm, each ingress router independently carries out decision-making according to the link loading information collected;

2. can make real-time response to offered load change fast, flow switches fast between shortest path tree and spanning tree;

3. between network energy-saving efficiency and offered load elasticity, obtain good balance.

Accompanying drawing explanation

Fig. 1. Global Topological and spanning tree/connected subgraph,

Fig. 1 .1 Global Topological,

Fig. 1 .2 spanning tree/connected subgraph (thick line portion).

Fig. 2. " destination address+label " forwards schematic diagram.

Fig. 3. label resets schematic diagram.

Fig. 4. Routing Protocol flow chart,

Fig. 4 .1 Path selection flow chart,

Fig. 4 .2 packet forwarding process figure.

Embodiment

As shown in Fig. 1 .1, an extreme case of energy-saving efficiency and network resilience contradiction is exactly that at this time network energy consumption is maximum when all links are all in running order, but also the most reliable and high resilience simultaneously, burst flow spike and link failure can be tackled.Another extreme case is shown in that Fig. 1 .2 is that all links on the connected subgraph that comprises all nodes are in running order, and other links are all in resting state.If online subgraph is taken as a spanning tree, then this time network energy-saving most effective, but be also most fragile simultaneously.Consider that thorough energy-saving routing protocol not only should consider energy-saving efficiency, network resilience and global network performance should be considered simultaneously comprehensively for one.In addition, because it is based on real-time traffic demand that Link State switches, our energy-saving routing protocol needs to make a policy fast, and keeps consistency in complete topological scope.Our the energy-saving routing protocol main thought of research is according to the actual traffic load situation of network, realizes switching level and smooth as far as possible between two kinds of extreme cases.Time traffic demand is low, utilizes the link in spanning tree to transmit flow as far as possible, fractional energy savings is maximized; Time traffic demand increases, little by little flow is moved on Global Topological from spanning tree, wake necessary link up to keep network resilience and performance, until all flows all choose shortest path, at this time agreement converges to the situation of OSPF automatically.It is level and smooth as much as possible that the focus of energy-saving routing protocol of our research is to make such switching, makes packet loss and out of orderly to minimize, to such an extent as to concerning upper-layer protocol application because the energy-conservation impact brought minimizes.

Workflow:

I) first each router periodically detects the loading condition of direct connected link, and this link loading information is flooded to whole network together with link-state information, and the LSA flooding mechanism of OSPF itself can be used to realize.

Ii) so far, in topology, each router all has identical network topological information and link loading information, pass through topology information, router can calculate shortest path and the spanning tree path of oneself arriving other any node of network, and the identical topology owing to using, unified algorithm, so all-router calculating path result keeps consistency, meets optimum minor structure characteristic.

Iii) then, each ingress router, according to the path uplink load state of data flow process, for each stream being entrance with it selects suitable path, and adds selection result to data message head as label, then forward according to " destination address+label ", see Fig. 2.

Iv) when downstream node receives the tape label message of upstream forwarding, directly forward according to " destination address+label ".

V) when running into forwarding port links and being in resting state, in order to ensure the continuity flowed, be waken up period at link, forward node path can forward the label that the label of packet resets to along spanning tree again, no longer carry out label replacement after link wakeup, see Fig. 3.

For improving the reliability of network topology, the actual online subgraph adopted should be increase redundancy to a certain extent on the basis of spanning tree, a kind of feasible scheme finds such subgraph to make each node on some rings, comprise the limit of minimal number, so online subgraph can successfully manage the situation that single-link lost efficacy simultaneously.

We test in 3 real topologys, find that the power-saving mechanism of spanning tree and shortest path tree combination can save the line card consumed energy of 20% ~ 50% when link utilization is lower, the object that invention achieves expection is described.

Claims (2)

1. the energy-saving routing method that is combined with spanning tree of shortest path tree, is characterized in that, network topology realizes successively according to the following steps:

Step (1), network topology initialization: on the basis of standard Link State Routing Protocol, increases resting state on every bar link that wherein each router node connects;

Step (2), each router node periodically detects the loading condition of all direct connected links, use the LSA of open type shortest path priority protocol OSPF mechanism LSA itself that link loading information is flooded in network topology together with link-state information, make each router node in described network topology all have identical network topological information and link loading information;

Step (3), each router node calculates shortest path and the spanning tree path of oneself other arbitrary router node on network topology according to the result obtained from step (2), generate routing table, and the result of calculation of all-router node is consistent;

Step (4), each router node in described network topology is according to the situation of the path uplink load of data flow process, be that each data flow selects a suitable path by destination address, select corresponding routing table, and selection result is added to the head of data message as label, forward by " destination address+label " again, determine route next jump in the routing table according to label;

Step (5), when downstream router node receive forwarded by upstream router with the message of label after, select down hop according to label, forward by the form of " destination address+label ";

Step (6), after core router node receives a message, check the link forwarding end, if the link forwarding end is normal, then normally forward by label, if when finding that the link of forwarding end is in resting state, need this dormancy link wakeup, be that the label of spanning tree forwards again by the tag modification of this datagram, until arrive object router.

2. the energy-saving routing method that is combined with spanning tree of shortest path tree according to claim 1, it is characterized in that, described spanning tree constructs one again for the actual online subgraph adopted, each router node on it is on some links of described spanning tree, also to comprise the limit of minimum number, lose efficacy to prevent single-link.