CN1859298A

CN1859298A - Path selecting method

Info

Publication number: CN1859298A
Application number: CNA2005101359826A
Authority: CN
Inventors: 张华琛; 谢小强; 吴志明; 邓一鸥; 张进
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2005-10-26
Filing date: 2005-12-29
Publication date: 2006-11-08
Anticipated expiration: 2025-12-29
Also published as: CN100438503C

Abstract

The present invention discloses a selection path method. It contains A, start router judging whether existing not needing occupying other LSP route, if existing then executing step B, otherwise executing step C; B, selecting one route in not needing occupying other LSP route and ending said process; C, selecting equifinality occupying least LSP number link located route in needed occupying other LSP route. The present invention solves problem of low priority LSP frequently being occupied and low priority LSP flow rate frequently being interrupted, greatly raising network stability and link utilization ratio.

Description

A kind of selection route method

Technical field

The present invention relates to multiprotocol label switching flow control in the communication technology, relate in particular to a kind of selection route method.

Background technology

According in traditional internet protocol about the inside routing gateway agreement (IGP) of Link State, router adopts SPF (SPF) algorithm to select the shortest path as route in the communication network, does not consider the bandwidth considerations in path.When shortest path was in congestion state, even other sub-optimal paths are in idle condition, router can not select idle sub-optimal path as route yet, caused in the communication network distributed pole of network traffics unbalanced.

Multi-protocol label switching traffic engineering (MPLS TE) is paid close attention to the optimization of communication network overall performance, takes all factors into consideration the bandwidth considerations in path, equiblibrium mass distribution network traffics on each paths of communication network.Operator utilizes MPLS TE can accurately control the path that flow is flowed through, thereby can avoid congested node, solve a part of path overload, the problem of another path free time, the Internet resources that operator is provided are fully utilized, and the overall performance of communication network is optimized.

The above-mentioned functions of MPLS TE is realized by MPLS TE structure.As shown in Figure 1, Fig. 1 is the MPLSTE structural representation.MPLS TE structure mainly comprises 4 basic composition unit: message retransmission unit 101, information release unit 102, path selection unit 103 and signaling unit 104.

Wherein, message retransmission unit 101 is used to guide IP bag stream to pass through network along predetermined path.Described predetermined path is based on that label determines, is known as label switched path (LSP), and promptly service traffics flow to the path of purpose router by certain orientation from initial router.Because LSP is based on that label determines, the shortest path for the arrival purpose router selected by existing IGP agreement is not restricted, so can avoid shortest path between initial router selection self and the purpose router as route.

Information release unit 102 is used to issue link-state information, network topological information and network load information.MPLS TE needs the information of some related network topological sum offered loads when calculating constrained path, for example maximum link bandwidth, maximum reservable bandwidth, current bandwidth reserved, current bandwidth are used and link attribute etc., and these information are issued by existing IGP agreement is expanded.When existing IGP agreement is expanded, generally be in Intermediate System-to-Intermediate System (IS-IS) agreement, to introduce new type lengths values (tlv), perhaps in Open Shortest Path First (OSPF) agreement, introduce new LSA (LSA).The router of MPLSTE manages network topological information and network load information by a special traffic engineering database (TEDB).Constrained path when TEDB is used to calculate LSP by physical network, the IGP link state database of shortest path is separate when being used to calculate LSP by physical network.

Path selection unit 103 is used for according to the network topological information of TEDB and network load information, the path of adopting Constraint Shortest Path First (CSPF) algorithm computation to satisfy constraints.CSPF is a kind of improved shortest-path first algorithm, when the shortest path that calculates by network, specific constraints is also taken into account, at first in the current network topological structure, delete node and the link that does not satisfy constraints, and then according to SPF algorithm computation shortest path.Here, specific constraints mainly comprises bandwidth demand, maximum jump number and management strategy demand etc.

Signaling unit 104 is used for dynamically setting up LSP.Signaling unit is dynamically set up the trouble that LSP can avoid the hop-by-hop configuration.The LSP of common not belt restraining can set up by tag distribution protocol (LDP), and the LSP of belt restraining can set up by constraint tag distribution protocol (CR-LDP) or resource reservation protocol flow engineering (RSVP TE).

As shown in Figure 2, Fig. 2 is for adopting the schematic diagram in the CSPF algorithm selection path among the MPLS TE.Suppose that all bandwidth are that the routing metric value (Metric) of link of 1G is all identical, all bandwidth are that the Metric of link of 155M is also identical, and set up router R1 and be high priority LSP1:R1 → R2 → R5 of 0 to R5 priority, the bandwidth that LSP1 takies is 155M, also having set up router R3 is low priority LSP2:R3 → R2 → R6 of 2 to R6 priority, and bandwidth that LSP2 takies also is 155M.

When between router R2 and the R5 during link occurs fault, the head end router R1 of LSP1 adopts the CSPF algorithm among the MPLSTE that LSP1 is redeveloped into: R1 → R2 → R6 → R5.Because the bandwidth of link has only 155M between router R2 and the R6, so the link between router R2 and the R6 is seized by newly-built LSP1 among the LSP2, and the head end router R3 of LSP2 adopts the CSPF algorithm among the MPLS TE that LSP2 is redeveloped into: R3 → R4 → R5 → R6.Like this, the link among the LSP2 between router R2 and the R6 is seized, and LSP2 needs to rebuild, and the flow on the LSP2 also is forced to interrupt, and it is unstable that therefore network becomes.

Select the path can solve the problem of network traffics skewness weighing apparatus to a certain extent though adopt the CSPF algorithm among the MPLS-TE; but because the CSPF algorithm among the MPLS-TE has ignored whether need the quantity seizing the link among other LSP and seize link among other LSP when selecting the path; may be removed to seize other more links among the low priority LSP again by the LSP that seized, so adopt the CSPF algorithm among the MPLS-TE to select the path to bring following problem through regular meeting:

1, when the link that does not need to seize among other LSP, taken place to seize, caused the utilance of link in the whole network to reduce;

2, the quantity of seizing link when needs are seized link among other LSP is not minimum, the priority of being seized LSP is not minimum, removed to seize other more links among the low priority LSP again by the LSP that seized, low priority LSP frequently is established and seizes, the flow of low priority LSP also frequently is interrupted, and causes network upheaval and unstable.

Summary of the invention

In view of this, main purpose of the present invention is to provide a kind of selection route method, to improve the utilance and the stability of network of link.

For achieving the above object, the invention provides a kind of selection route method, may further comprise the steps:

A, initial router judge whether to exist the path that does not need to seize other label switching path LSP, if existence, then execution in step B; Otherwise, execution in step C;

B, in not needing to seize the path of other LSP, select a paths, and process ends;

C, seize at needs and to select equivalence to seize the path at the link place of LSP minimum number in the path of other LSP.

In the such scheme, judge whether to exist the path that does not need to seize other LSP to be described in the steps A: initial router judges between self and the purpose router whether have the path that available bandwidth resources can both satisfy new business flow needs on the whole links at least.

In the such scheme, in not needing to seize the path of other LSP, select a paths to comprise described in the step B: not needing to seize in the path of other LSP and selecting the path that link utilization is minimum.

In the such scheme, describedly in not needing to seize the path of other LSP, select the minimum path of link utilization to comprise:

B1, in every path that does not need to seize other LSP, select the poorest link of index;

B2, the link that the index of selecting is the poorest constitute a set, select the link of an index optimum in the set that the poorest link of index constitutes;

B3, with the link of the index optimum selected as the minimum link of link utilization, select the path at this link place.

In the such scheme, described step B1 comprises:

B11, suppose F (link (uv))=(SB+UB (uv))/RB (uv), wherein, reservation total bandwidth on RB (uv) the expression link link (uv), the occupied total bandwidth on UB (uv) the expression link link (uv), SB represents the bandwidth that newly-built LSP is required;

B12, calculate F (link (the uv)) value of every link in every path that does not need to seize other LSP, the size of more every link F (link (uv)) value selects F (link (uv)) to be worth the link of maximum as the poorest link of index.

In the such scheme, there are many simultaneously in the maximum link of F described in the step B12 (link (uv)) value, this method further comprises: calculate and compare (RB-SB-UB) value of F (link (uv)) value maximum link, select the minimum link of (RB-SB-UB) value as the poorest link of index.

In the such scheme, there are many simultaneously in the minimum link of described (RB-SB-UB) value, and this method further comprises: in the link of described many (RB-SB-UB) values minimums, select a link as the poorest link of index at random.

In the such scheme, in the set that the poorest link of index constitutes, select the link of an index optimum to comprise described in the step B2: to calculate and the size of every link F (link (uv)) value in the set that constitutes of the poorest link of index relatively, selects a F (link (uv)) to be worth the link of the link of minimum as the index optimum.

In the such scheme, there are many simultaneously in the minimum link of described F (link (uv)) value, this method further comprises: calculate and compare (RB-SB-UB) value of F (link (uv)) value smallest link, select the link of the maximum link of (RB-SB-UB) value as the index optimum.

In the such scheme, there are many simultaneously in the maximum link of described (RB-SB-UB) value, this method further comprises: in the path under described many (RB-SB-UB) value maximum link, reject the big link of each self-contained described (RB-SB-UB) value respectively, and execution in step B1 and B2 once more, until the link of selecting an index optimum.

In the such scheme, described link in certain paths is all rejected in the process of rejecting the big link of each self-contained described (RB-SB-UB) value, and the path of selecting among the step B3 is the path that described link is all rejected.

In the such scheme, in not needing to seize the path of other LSP, select a paths to comprise described in the step B: not needing to seize in the path of other LSP and selecting the path that number of links is minimum.

In the such scheme, describedly in not needing to seize the path of other LSP, select the minimum path of number of links to comprise:

B1 ', in not needing to seize the path of other LSP, calculate the quantity of link that every paths comprises;

The quantity of B2 ', the link that every paths comprises that relatively calculates is selected the minimum path of number of links.

In the such scheme, there are many simultaneously in the minimum path of number of links described in the step B2 ', this method further comprises: the path that number of links is minimum constitutes a set, suppose P (path (u))=F (link (u1))+F (link (u2))+... F (link (un)), F (link (uv))=(SB+UB (uv))/RB (uv) wherein, according to formula P (path (u))=F (link (u1))+F (link (u2))+... F (link (un)) calculates P (path (the u)) value of every paths in this set, selects the minimum path of P (path (u)) value.

In the such scheme, there are many simultaneously in the minimum path of described P (path (u)) value, and this method further comprises: select a paths at random in the path of described many P (path (u)) value minimum.

In the such scheme, described step C comprises:

C1, inner routing gateway agreement IGP is expanded, in every needs are seized the path of other LSP, select the poorest link of index;

C2, the link that the index of selecting is the poorest constitute a set, select the link of an index optimum in the set that the poorest link of index constitutes;

C3, the link of the index optimum selected is seized the link of LSP minimum number as equivalence, select the path at this link place.

In the such scheme, described path is the unicast path of point-to-point, and described step C1 comprises:

C11, in the Intermediate System-to-Intermediate System Intermediate System to Intermediate System of IGP, introduce new type lengths values TLV, perhaps in IGP Open Shortest Path First ospf protocol, introduce new LSA LSA, in new TLV that introduces or LSA, deposit quantity, priority level and the bandwidth-level information of LSP on every link;

C12, suppose the relational expression between E (link (uv)) and the LSP (uvrt), wherein E (link (uv)) represents the equivalent quantity of seizing LSP on certain bar link, and the priority level of the last v bar of LSP (uvrt) expression path u link is the quantity that the LSP of t is seized for the r bandwidth-level; With the relational expression between quantity, priority level and described E of bandwidth-level information substitution (link (uv)) and the LSP (uvrt) of LSP on every link, calculate E (link (the uv)) value of every link;

C13, seize the size of more every link E (link (uv)) value in the path of other LSP at every needs, the link that E (link (uv)) value is maximum is as the poorest link of index in this path.

In the such scheme, described path is a multicast path to multiple spot, and described step C1 comprises:

C11 ', in the Intermediate System to Intermediate System of IGP, introduce new TLV, perhaps in the ospf protocol of IGP, introduce new LSA, in new TLV that introduces or LSA, deposit quantity, priority level, bandwidth-level and the multicast group address information of LSP on every link;

C12 ', suppose the relational expression between E (link (uv)) and the LSP (uvrt), wherein E (link (uv)) represents the equivalent quantity of seizing LSP on certain bar link, LSP (uvrt)=LSPs (uvrt)+LSPM1 (uvrt)+LSPM2 (uvrt)+...+LSPMn (uvrt), the priority level of the last v bar of LSPs (uvrt) expression path u link is the quantity that the clean culture LSP of t is seized for the r bandwidth-level, and the priority level that LSPMn (uvrt) represents the last v bar of path u link is the quantity that the multicast path n of t is seized for the r bandwidth-level; With the relational expression between quantity, priority level, bandwidth-level and described E of multicast group address information substitution (link (uv)) and the LSP (uvrt) of LSP on every link, calculate E (link (the uv)) value of every link;

C13 ', seize the size of more every link E (link (uv)) value in the path of other LSP at every needs, the link that E (link (uv)) value is maximum is as the poorest link of index in this path.

In the such scheme, there are many simultaneously in the maximum link of E described in step C13 or the C13 ' (link (uv)) value, this method further comprises: the summation of all LSP quantity of being seized on the link of calculating and more simultaneous many E (link (uv)) value maximum, and select all links of being seized LSP quantity summation maximum as the poorest link of index.

In the such scheme, there are many simultaneously in the link of the summation maximum of the described LSP quantity of being seized, and this method further comprises: select a link as the poorest link of index at random in the link of the summation maximum of the LSP quantity that described many quilts are seized.

In the such scheme, in the set that the poorest link of index constitutes, select the link of an index optimum to comprise described in the step C2: to calculate and the size of every link E (link (uv)) value in the set that constitutes of the poorest link of index relatively, selects an E (link (uv)) to be worth the link of the link of minimum as the index optimum.

In the such scheme, there are many simultaneously in the minimum link of described E (link (uv)) value, this method further comprises: calculate also many bar E (link (uv)) value smallest link and seized the size of LSP quantity summation, select a quilt to seize the link of the link of LSP quantity summation minimum as the index optimum.

In the such scheme, there are many simultaneously in the link of the summation minimum of the described LSP quantity of being seized, this method further comprises: in the path under the summation smallest link of the LSP quantity that many quilts are seized, reject the link of the summation minimum of each self-contained described LSP quantity of being seized respectively, and execution in step C1 and C2 once more, until the link of selecting an index optimum.

In the such scheme, in the process of described link in the summation minimum of rejecting each self-contained described LSP quantity of being seized, the link in certain paths is all rejected, and the path of selecting among the step C3 is the path that described link is all rejected.

Therefore, this selection route method provided by the invention, by judging whether to exist the path that does not need to seize other LSP, if exist, then initial router do not need to select to seize the path in the path of other LSP; Otherwise initial router is seized at needs and is selected equivalence to seize the path at the link place of LSP minimum number in the path of other LSP.

Utilize the present invention, when the link that does not need to seize among other LSP, initial router do not need to select to seize the path in the path of other LSP, has avoided seizing when the link that does not need to seize among other LSP.Therefore, one aspect of the present invention has improved whole stability of network, also makes the flow distribution of whole network be tending towards balanced on the other hand, has improved the utilance of link in the whole network greatly.In addition, when the link that does not need to seize among other LSP, the minimum path of link utilization among the LSP that the further selection of router does not need to seize, perhaps further selection does not need to seize the minimum path of number of links among other LSP, further make the flow distribution of whole network be tending towards balanced, and further improved the utilance and the whole stability of network of link in the whole network.

Utilize the present invention, when needs are seized link among other LSP,, taken all factors into consideration the LSP priority level of being seized and seized the factor of number of links two aspects of being seized among the LSP for the unicast path of selecting point-to-point; For the multicast path of choice point to multiple spot, not only take all factors into consideration the LSP priority level of being seized and seized the factor of seizing LSP quantity two aspects on the link, but also considered to seize link multicast path of living in, and seize whether link overlaps two aspects with the link of having set up that belongs to same multicast path factor in the quantity of seizing branch's link that the link downstream had.So, make the LSP that is seized can not remove to seize link among other LSP again, solved low priority LSP and frequently be established and seize, the also frequent interrupted problem of the flow of low priority LSP is so the present invention has improved stability of network greatly.

Description of drawings

Fig. 1 is a MPLS TE structural representation;

Fig. 2 is for adopting the schematic diagram in the CSPF algorithm selection path among the MPLS TE;

Fig. 3 selects the realization flow figure of path overall technological scheme for the present invention;

Fig. 4 seizes the schematic diagram in the path, link place of LSP minimum number for selecting equivalence under the unicast case;

Fig. 5 seizes the schematic diagram in the path, link place of LSP minimum number for selecting equivalence under the multicast scenarios;

Fig. 6 seizes LSP minimum number link place route method flow chart for the present invention selects equivalence;

Fig. 7 selects the minimum route method flow chart of link utilization for the present invention in not needing to seize the path of other LSP;

Fig. 8 selects the minimum route method flow chart of number of links for the present invention in not needing to seize the path of other LSP.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, by the following examples, and with reference to accompanying drawing, the present invention is described in more detail.

Core content of the present invention is: by judging whether to exist the path that does not need to seize other LSP, if exist, then initial router do not need to select to seize the path in the path of other LSP; Otherwise initial router is seized at needs and is selected equivalence to seize the path at the link place of LSP minimum number in the path of other LSP.

As shown in Figure 3, Fig. 3 selects the realization flow figure of path overall technological scheme for the present invention, and this method may further comprise the steps:

Step 301: initial router judges whether to exist the path that does not need to seize other LSP, if exist, then execution in step 302; Otherwise, execution in step 303;

Step 302: not need to select to seize the path in the path of other LSP, and process ends;

Step 303: seize at needs and to select equivalence to seize the path at the link place of LSP minimum number in the path of other LSP.

Above-mentioned steps 301 judges whether to exist the path that does not need to seize other LSP, be that initial router judges between self and the purpose router whether have the path that available bandwidth resources can both satisfy new business flow needs on the whole links at least, if, then have the path that does not need to seize other LSP, initial router does not need to seize the link among other LSP yet; Otherwise, there is not the path that does not need to seize other LSP, initial router need be seized the link among other LSP.

If promptly between initial router and purpose router, have a paths at least, in this path on every link usable bandwidth resources can both satisfy the needs of new business flow, then initial router judges that between initial router and purpose router existence does not need to seize the path of other LSP.If between initial router and purpose router, there is not a paths as described below, in this path on every link usable bandwidth resources can both satisfy the needs of new business flow, then initial router is judged do not have the path that does not need to seize other LSP between initial router and purpose router.

In above-mentioned steps 302, be tending towards balanced for network traffics are distributed, and improve the utilance of link in the whole network, exist when not needing to seize the path of other LSP, initial router is selected a paths in not needing to seize the path of other LSP.In addition, optimization as technical solution of the present invention, for being distributed, network traffics are tending towards balanced more, and further improve the utilance of link in the whole network, when existence does not need to seize the path of other LSP, initial router is selected the path that link utilization is minimum in not needing to seize the path of other LSP, perhaps select a path that number of links is minimum.

Because LSP generally has 0,1 ..., eight priority levels such as 7, and priority is successively decreased successively from 0 to 7, after link among the high LSP of priority level is seized, will seize other priority levels, cause the upheaval of network and unstable than the link among self low LSP.Therefore, after making the link of initial router in seizing other LSP, the LSP that is seized no longer removes to seize other LSP, reduces the influence to whole network by port oscillation, improve stability of network, initial router should preferentially select the link among the minimum LSP of priority level to seize.

Because the quantity of the link that initial router need be seized in different LSP may be different, every quilt is seized link and may be belonged to many LSP simultaneously again, the quantity of LSP is many more under the link that initial router need be seized, the quantity of seizing LSP is also just many more, and then also just big more to the influence of whole network by port oscillation.Therefore, for reducing the influence to whole network by port oscillation, improve stability of network, initial router also should preferentially be selected to seize the path at the link place of seizing the LSP minimum number on the link and seize.

When above-mentioned steps 303 is seized the path at the link place of selecting equivalence to seize the LSP minimum number in the path of other LSP at needs, for the unicast path of selecting point-to-point, need take all factors into consideration the above-mentioned LSP priority level of being seized and seize the factor of seizing LSP quantity two aspects on the link.For the multicast path of choice point, not only need to take all factors into consideration the above-mentioned LSP priority level of being seized and seize the factor of seizing LSP quantity two aspects on the link, but also need to consider the factor of following two aspects to multiple spot:

One, seizes link multicast path of living in the quantity of seizing branch's link that the link downstream had.

If on certain bandwidth-level of certain priority level of certain link, have many LSP, and algorithm has only calculated need seize a part of LSP, then should preferentially be chosen in for the initial router of multicast path and seize the link downstream and have the minimum multicast path of branch's number of links and seize; For unicast path, be 0 because the downstream has branch's number of links, so can at will seize one.

For multicast path, because after selecting to seize the residing multicast path of link, business on this multicast path downstream branch link also will be forced to cut off, so, if it is many more in the quantity of seizing branch's link that the link downstream had to seize link multicast path of living in, the then professional link that is forced to cut off also will be many more, so also will be serious more to the influence of whole network by port oscillation.Therefore, be to reduce the influence to whole network by port oscillation, improve stability of network, initial router should preferentially be chosen in to be seized the link downstream and has the minimum multicast path of branch's number of links and seize.

Whether two, seize link overlaps with the link of having set up that belongs to same multicast path.

Overlap with the link of having set up that belongs to same multicast path if seize link, then can directly receive the multicast packet that overlaps link transmission, overlapping and seizing LSP quantity on the link is 0, does not promptly seize at the coincidence link.Therefore, initial router should preferentially select to seize the multicast path that link overlaps with the link of having set up that belongs to same multicast path.

The equivalent quantity of seizing LSP can calculate by the relational expression between E (link (uv)) and the LSP (uvrt) on the link, and the relational expression between E (link (uv)) and the LSP (uvrt) is as follows:

E(link(uv))＝(1/127)(LSP(uv71)/(1+2+...+2^(t-1))+...+LSP(uv7t)*2^(t-1)/(1+2+...+2^(t-1)))

+(2/127)(LSP(uv61)/(1+2+...+2^(t-1))+...+LSP(uv6t)*2^(t-1)/(1+2+...+2^(t-1)))

+...

+(64/127)(LSP(uv11)/(1+2+...+2^(t-1))+...+LSP(uv1t)*2^(t-1)/(1+2+...+2^(t-1)))

Wherein, E (link (uv)) represents the equivalent quantity of seizing LSP on certain bar link, and for the unicast path of selecting point-to-point, the priority level of the last v bar of LSP (uvrt) expression path u link is the quantity that the LSP of t is seized for the r bandwidth-level; For the multicast path of choice point to multiple spot, LSP (uvrt)=LSPs (uvrt)+LSPM1 (uvrt)+LSPM2 (uvrt)+...+LSPMn (uvrt), wherein, the priority level of the last v bar of LSPs (uvrt) expression path u link is the quantity that the clean culture LSP of t is seized for the r bandwidth-level, and the priority level that LSPMn (uvrt) represents the last v bar of path u link is the quantity that the multicast path n of t is seized for the r bandwidth-level.

Below in conjunction with clean culture and two kinds of situations of multicast, describe initial router in detail and seize at needs and select equivalence to seize the path at the link place of LSP minimum number in the path of other LSP.

One,, selects to seize the equivalent path of seizing the link place of LSP minimum number on the link for the unicast path of selecting point-to-point.

As shown in Figure 4, Fig. 4 seizes the schematic diagram in the path, link place of LSP minimum number for selecting equivalence under the unicast case.Suppose to have path 1:A → B → E → C and path 2:A → D → E → C two paths, below respectively path 1 and path 2 investigated:

For path 1, suppose that link AB and EC need seize in the path 1 from other LSP, and link AB belongs to 3 LSP, wherein 1 is that 1 bandwidth-level is 3 LSP for priority level, other 2 is that 3 bandwidth-levels are 2 LSP for priority level, the total 1K of the LSP that is seized, three kinds of bandwidth-levels of 2K and 4K then can calculate link AB according to the relational expression between E under the above-mentioned unicast case (link (uv)) and the LSP (uvrt) and go up the quantity that equivalence seizes LSP and be: E (link (uv))=(64/127) (2^ (3-1)/(1+2+4))+(16/127) ((2^ (2-1)+2^ (2-1))/(1+2+4))=0.36.

Suppose that link EC belongs to 2 LSP simultaneously, wherein one is that 2 bandwidth-levels are 3 LSP for priority level, other one for priority level is that 3 bandwidth-levels are 2 LSP, then can calculate link EC and go up the quantity that equivalence seizes LSP and be: E (link (uv))=(32/127) (2^ (3-1)/(1+2+4))+(16/127) ((2^ (2-1))/(1+2+4))=0.18 according to the relational expression between E under the above-mentioned unicast case (link (uv)) and the LSP (uvrt).

The E that relatively calculates (link (uv)) value is selected the bigger link of E (link (uv)) value, and promptly the link of selecting in path 1 is AB.

For path 2, suppose that link AD, DE and EC need to seize in path 2 from other LSP, calculate E (link (the uv)) value of link AD, DE and EC respectively according to the relational expression between LSP under each link and above-mentioned E (link (uv)) and the LSP (uvrt), relatively the E (link (uv)) of link AD, DE and EC is worth then, selects the maximum link of E (link (uv)) value.Suppose that in the present embodiment the link of selecting is DE in path 2.

It is maximum that E (link (uv)) value is all selected in above-mentioned path 1 and path 2, and promptly after the poorest link of index, E (link (the uv)) value of each link relatively in the link of selecting is once more selected the path at the link place of E (link (uv)) value minimum.In the present embodiment, promptly select link AB and select in path 2 after the link DE in path 1, the E (link (uv)) of link AB and DE value is relatively once more selected the path at the less link place of E (link (uv)) value among link EC and the DE.

Seize on the link path that the link place of LSP minimum number is seized in equivalence according to aforesaid way at what the unicast path of point-to-point was selected, be and taken all factors into consideration the LSP priority level of being seized and seized the path of seizing LSP quantity two aspect factors on the link.

When selecting to seize the path at the link place that equivalence on the link seizes the LSP minimum number at the unicast path of point-to-point, utilized the quantity of LSP on the link, priority level and bandwidth-level information, this information is not announced in existing IGP agreement.Therefore, in order to make router when needs are seized link among other LSP, can be according to quantity, priority level and the bandwidth-level information of LSP on the link, select equivalence to seize the path at the link place of LSP minimum number, the present invention further strengthens the function of the information release unit in the MPLS TE structure, existing IGP agreement is expanded, be used to issue quantity, priority level and the bandwidth-level information of LSP on the link.

When existing IGP agreement is expanded, because the IGP agreement mainly comprises Intermediate System to Intermediate System and ospf protocol, so generally be in Intermediate System to Intermediate System, to introduce new TLV, perhaps in ospf protocol, introduce new LSA, in new TLV that introduces or LSA, deposit quantity, priority level and the bandwidth-level information of LSP on the link.

Two,, select to seize the equivalent path of seizing the link place of LSP minimum number on the link for the multicast path of choice point to multiple spot.

As shown in Figure 5, Fig. 5 seizes the schematic diagram in the path, link place of LSP minimum number for selecting equivalence under the multicast scenarios.Suppose to have 6 Label Switching Routers (LSR): LSR1, LSR2, LSR3, LSR4, LSR5 and LSR6, bandwidth on link 1, link 2 and the link 5 is 16M, the bandwidth of link 3, link 4 and link 6 is 32M, and to have set up following 4 priority levels be the t multicast path for the r bandwidth-level:

LSP1:LSR1 → LSR2 → LSR4, multicast group address are D1, and occupied bandwidth is 16M, path shown in "-" among the figure;

LSP2:LSR1 → LSR3 → LSR6, multicast group address are D2, and occupied bandwidth is 16M, path shown in "----" among the figure;

Multicast group address is D3, and occupied bandwidth is 16M, path shown in "----" among the figure;

LSP4:LSR2 → LSR5, clean culture LSP, occupied bandwidth are 16M, path shown in "---" among the figure.

LSR5 wants to add the multicast that multicast group address is D1 now, required bandwidth is 16M, LSR1 according to the information of preserving among the TED find two all needs seize the path candidate LSP5 and the LSP6 of link, LSP5:LSR1 → LSR2 → LSR5 wherein, path shown in "---" among the figure; LSP6:LSR1 → LSR3 → LSR5, path shown in "---" among the figure.Below respectively LSP5 and LSP6 are investigated:

For LSP5, LSP5 is made of link 1 and link 2 because link 1 belongs to multicast group address D1, be one built up can be shared link, so, on link 1, do not seize.Because the bandwidth of link 2 is 16M, the clean culture LSP4 that on the link 2 occupied bandwidth to be arranged be 16M, so, need seize the link 2 among the LSP4.Therefore, link 2 is the poorest link of index in LSP5.

For LSP6, LSP6 is made of link 3 and link 4, because the bandwidth of link 4 is 32M, link 4 has been taken 16M by path LSP3, remaining available bandwidth is 32-16=16M, can satisfy LSR5 adding multicast group address is the bandwidth demand of the multicast of D1, so, on link 4, do not seize.Because the bandwidth of link 3 is 32M, link 3 has been taken 16M respectively by path LSP2 and LSP3, and remaining available bandwidth is 0, so, need seize the link 3 among LSP2 or the LSP3.

When selecting to seize LSP2 or LSP3, because LSP2 has 1 branch node LSR6 in the downstream of link 3, LSP3 has 2 branch node LSR5 and LSR6 in the downstream of link 3, if seize the link 3 among the LSP2, the then equivalent quantity of seizing link is 2=1 (link 3 is)+1 (downstream links 6 of link 3) own; If seize the link 3 among the LSP3, the then equivalent quantity of seizing link is 3=1 (link 3 is)+2 (downstream links 5 of link 3 and links 6) own.Therefore, seize the influence that the multicast downstream links is caused, select to seize the link 3 among the LSP2 in order to reduce as far as possible.Certainly, determined that link 3 is the poorest link of index in LSP6 this moment.

After above-mentioned LSP5 and LSP6 selected the poorest link of index, E (link (the uv)) value of each link relatively in the link of selecting was once more selected the path at the link place of E (link (uv)) value minimum.

For link 2 and link 3, because the link 2 clean culture LSP that need to seize an occupied bandwidth be 16M, the quantity that link is seized in its equivalence is 1; And link 3 need be seized a multicast path LSP2, and the quantity that link is seized in its equivalence is 2, so, select equivalence to seize the path at the few link place of the quantity of link, promptly select the path LSP4 at link 2 places to seize.

Seize on the link path that the link place of LSP minimum number is seized in equivalence according to aforesaid way at what the multicast path of putting multiple spot was selected, not only take all factors into consideration the LSP priority level of being seized and seized the factor of seizing LSP quantity two aspects on the link, and considered to seize link multicast path of living in, and seize whether link overlaps two aspects with the link of having set up that belongs to same multicast path factor in the quantity of seizing branch's link that the link downstream had.

Above-mentioned when selecting to seize the path at the link place that equivalence on the link seizes the LSP minimum number at the multicast path of putting multiple spot, except increasing quantity, priority level and the bandwidth-level information of LSP on the issue link, also need to increase the multicast group address information of every LSP correspondence on the issue link.The multicast group address information of every LSP correspondence on the link also is stored when existing IGP agreement is expanded and introduces new TLV in Intermediate System to Intermediate System, perhaps introduces among the new LSA in ospf protocol.

At this moment, the information that information issue assembly is announced increases, and each node flow engineering data base (TED) is for to safeguard that the informational needs of these announcements expends more internal memory.In order to reduce the consumption of internal memory, the present invention has defined the maximum number N that allows multicast LSP on the link, is come the scale of list item among the quantity of restricted information issue and the TED by N.When selecting path candidate, N is as a constraints, and when the number of multicast LSP on the link during more than or equal to N, the path candidate at this link place will be directly disallowable.

This in addition, the maximum number N that definition allows multicast LSP on the link is service traffics in the scatternet naturally, and the business in the network is disperseed, and satisfy the characteristics and the demand of traffic engineering.

For this selection route method provided by the invention can more clearly be described, below in conjunction with specific embodiment and with reference to accompanying drawing, respectively initial router when needs are seized is selected route method, and initial router selects route method to be elaborated when not needing to seize.

Supposing the system allows to have at most t bandwidth-level, and t is big more, and bandwidth value is high more.All paths of supposing to satisfy constraint be path (1), path (2) ..., path (u) ..., path (g), path (u) comprises v bar link, be respectively link (u1), link (u2) ..., link (uv), wherein 1＜=u＜=g, and t, u, v and g are natural number.Suppose the reservation total bandwidth on RB (uv) the expression link link (uv), the occupied total bandwidth on UB (uv) the expression link link (uv), SB represents the bandwidth that newly-built LSP is required.

As shown in Figure 6, Fig. 6 seizes LSP minimum number link place route method flow chart for the present invention selects equivalence, and this method may further comprise the steps:

Step 601: determine that according to the priority level of LSP and bandwidth-level needs seize the path of other LSP.

For the unicast path of point-to-point, the concrete route method of determining to seize other LSP is as follows: suppose that the relational expression between E under the unicast case (link (uv)) and the LSP (uvrt) is:

+(2/127)(LSP(uv61)/(1+2+...+2^(t-1))+...+LSP(uv6t)*2^(t-1)/(1+2+...+2^(t-1)))

+...

+(64/127)(LSP(uv11)/(1+2+...+2^(t-1))+...+LSP(uv1t)*2^(t-1)/(1+2+...+2^(t-1)))

Wherein, E (link (uv)) represents the equivalent quantity of seizing LSP on certain bar link, and the priority level of the last v bar of LSP (uvrt) expression path u link is the quantity that the LSP of t is seized for the r bandwidth-level.

1), at first to all LSP according to being used for the priority that bandwidth resources are seized, respectively all LSP in each priority are pressed the size ordering of occupied bandwidth, form quantitative relation as shown in the formula expression:

Wi＝WLSPi1+WLSPi2+WLSPi3+......+WLSPin，

WLSPi1＞＝WLSPi2＞＝WLSPi3......＞＝WLSPin，

Wherein, Wi represent all LSP take among the priority i bandwidth and, WLSPi1, WLSPi2, WLSPi3 ..., WLSPin represents the bandwidth that each LSP takies among the priority i, carrying out the bandwidth demand of seizing LSP is PW=SB-(RB-UB), n is the total LSP quantity that contains among the priority i.

2), find out the j of a maximum, make W7+W6+......Wj＞=PW, wherein j is more than or equal to k, the highest priority level of k for seizing; If fail to find j, execution in step 7); Otherwise, continue execution in step 3);

3) if W7+W6+......Wj=PW, then priority 7 all LSP in priority j are seized, and execution in step 7); Otherwise, suppose PWj=PW-(W7+W6+......+W (j+1)), the false code algorithm that obtains j is as follows:

sum＝0；

for(i＝7；i＞＝0；i--)

{

sum＝sum+Wi；

if(sum＞＝PW)

{

j＝i；

Algorithm is finished;

}

4), the LSP that selection will be seized in priority j.

Find out the m of a minimum, make WLSPj1+WLSPj2+.....+WLSPjm＞=PWj, if WLSPj1+WLSPj2+.....+WLSPjm=PWj, then priority 7 all LSP and LSP WLSPj1, WLSPj2.....WLSPjm among the priority j in priority j+1 seized execution in step 7); Otherwise, in priority i, select m bar LSP, the bandwidth sum that makes this m bar LSP take be the bandwidth sum that takies of other any m bars greater than the minimum value in the PWj value, writing down this minimum value is FWs; If FWs=PWj, then priority 7 all LSP and above-mentioned m bar LSP among the priority j in priority j+1 seized execution in step 7); Otherwise above-mentioned m bar LSP is seized.

Suppose FW=FWs-PWj, N=j+1, the false code algorithm that obtains m is as follows:

sum＝0；

for(i＝1；i＜＝n；i++)

{

sum＝sum+WLSPji；

if(sum＞＝PWj)

{

m＝i；

Algorithm is finished;

}

5), the LSP that selection will be seized in priority N.

Find out the q of a minimum, make WLSP (j+1) n+WLSP (j+1) (n-1)+... ..+WLSP (j+1) q＜=FW.If can not obtain q, then all LSP among the priority j+1 are seized, and change 4 over to); Otherwise, if WLSP (j+1) n+WLSP (j+1) (n-1)+... ..+WLSP (j+1) q=FW, then priority 7 in j+2 all LSP and priority j+1 in occupied bandwidth be WLSP (j+1) 1, WLSP (j+1) 2 ..., WLSP (j+1) LSP (q-1) seized execution in step 7); Otherwise, in priority N, select q bar LSP, the bandwidth sum that makes this q bar LSP take be the bandwidth sum that takies of other any q bars less than bandwidth among the LSP of FW value and maximum, and to write down maximum be FWr; Except that this q bar LSP, other all LSP are seized in priority N.

Suppose FW=FW-Fwr, the false code algorithm that obtains j is as follows:

if(WLSP(j+1)n＞FW)

{

Can not get the q value, withdraw from;

}

q＝n；

sum＝WLSP(j+1)n；

for(i＝n-1；i＞＝0；i--)

{

sum＝sum+WLSP(j+1)i；

if(sum＞PW)

{

The q value is definite, and algorithm is finished;

}

else

{

q＝i；

}

6)、N＝N+1。If N＜=7, execution in step 2); Otherwise, execution in step 7).

7), finish.

For the unicast path of point-to-point, can determine that according to above-mentioned algorithm needs seize the path of other LSP.But, should determine to seize the path of other LSP in conjunction with following rule for the multicast path of putting multiple spot.Concrete rule is as follows:

If in the LSP of certain certain bandwidth-level of priority level of certain link, only seize the part of links among the LSP, then this LSP compares with other LSP and is seizing the minimum number that link data flows down branch's link that trip has.For the unicast path of point-to-point, can think and it seize link data to flow down the quantity that trip has branch's link be 0, so cast link just need not be considered this point.The purpose of doing like this is to avoid the multicast LSP that has than multiple-limb to be seized as far as possible, because rebuliding undoubtedly of it can bring bigger unsteadiness to network.

Step 602: the IGP agreement is expanded.

When the IGP agreement is expanded, generally be in Intermediate System to Intermediate System, to introduce new TLV, perhaps in ospf protocol, introduce new LSA.

For the unicast path of point-to-point, in new TLV that introduces or LSA, deposit quantity, priority level and the bandwidth-level information of LSP on the link.For the multicast path of putting multiple spot, in new TLV that introduces or LSA, not only deposit quantity, priority level and the bandwidth-level information of LSP on the link, and deposit the multicast group address information of every LSP correspondence on the link.

Step 603: seize at every needs and to select the poorest link of index in the path of other LSP.

Unicast path for point-to-point, with the relational expression between E (link (uv)) and the LSP (uvrt) under quantity, priority level and the above-mentioned unicast case of bandwidth-level information substitution of LSP on the link that increases, calculate E (link (the uv)) value of every link on every paths, the size of more every link E (link (uv)) value selects the maximum link of E in every paths (link (uv)) value as the poorest link of index; Wherein E (link (uv)) represents the equivalent quantity of seizing LSP on certain bar link, and the priority level of the last v bar of LSP (uvrt) expression path u link is the quantity that the LSP of t is seized for the r bandwidth-level.

For the multicast path of putting multiple spot, with the relational expression between E (link (uv)) and the LSP (uvrt) under quantity, priority level and the bandwidth-level information of LSP on the link that increases and the above-mentioned multicast scenarios of multicast group address information substitution, calculate E (link (the uv)) value of every link on every paths, the size of more every link E (link (uv)) value selects the maximum link of E in every paths (link (uv)) value as the poorest link of index; Wherein, LSP (uvrt)=LSPs (uvrt)+LSPM1 (uvrt)+LSPM2 (uvrt)+...+LSPMn (uvrt), wherein, the priority level of the last v bar of LSPs (uvrt) expression path u link is the quantity that the clean culture LSP of t is seized for the r bandwidth-level, and the priority level that LSPMn (uvrt) represents the last v bar of path u link is the quantity that the multicast path n of t is seized for the r bandwidth-level.

In the process of more every link E (link (uv)) value size, if there are many simultaneously in the maximum link of E in described every paths (link (uv)) value, then calculate and link that more simultaneous many E (link (uv)) value is maximum on the summation of all LSP quantity of being seized, select all links of being seized LSP quantity summation maximum as the poorest link of index.

In the process of the LSP quantity summations that all quilts are seized on the link of more simultaneous many E (link (uv)) value maximum, if there are many simultaneously in the link of the summation maximum of the described LSP quantity of being seized, then in the link of the summation maximum of the LSP quantity that described many quilts are seized, select a link at random as the poorest link of index.

Step 604: the link that the index of selecting is the poorest constitutes a set, selects the link of an index optimum in the set that the poorest link of index constitutes.

The set that the poorest link constitutes from index, select in the process of link of index optimum, at first calculate and E (link (the uv)) value of every link in the set that constitutes of the poorest link of index relatively, select the link of the link of E (link (uv)) value minimum as the index optimum;

In the process of selecting E (link (uv)) value smallest link, if there is the minimum link of many E (link (uv)) value simultaneously, then calculate and link that more simultaneous many E (link (uv)) value is minimum on the summation of all LSP quantity of being seized, select all to be seized the link of the link of LSP quantity summation minimum as the index optimum;

In the process of the LSP quantity summations that all quilts are seized on the link of more simultaneous many E (link (uv)) value maximum, if the link of the summation minimum of the described LSP quantity of being seized has many simultaneously, then in the path under the summation smallest link of the LSP quantity that many quilts are seized, reject the link of the summation minimum of each self-contained described LSP quantity of being seized respectively, and execution in step 603 and 604 once more, until the link of selecting an index optimum; If the link of the summation minimum of the described LSP quantity of being seized has only one, then select the link of this link as the index optimum.

Step 605: the link of the index optimum selected is seized the link of LSP minimum number as equivalence, select the path at this link place.

In addition, in step 604, if in the process of the link of the summation minimum of rejecting each self-contained described LSP quantity of being seized, the link in certain paths is all rejected, and then selects this paths.

Suppose that there is g ' bar in all paths of satisfying constraint, g ' paths be respectively path (1 '), path (2 ') ..., path (u ') ..., path (g '), path (u ') comprises v ' bar link, be respectively link (u ' 1 '), link (u ' 2 ') ..., link (u ' v '), wherein, 1 '＜=u '＜=g ', and u ', v ' and g ' are natural number.Suppose F (link (u ' v '))=(SB+UB (u ' v '))/RB (u ' v '), wherein, reservation total bandwidth on RB (u ' v ') the expression link link (u ' v '), occupied total bandwidth on UB (u ' v ') the expression link link (u ' v '), SB represents the bandwidth that newly-built LSP is required.

As shown in Figure 7, Fig. 7 selects the minimum route method flow chart of link utilization for the present invention in not needing to seize the path of other LSP, and this method may further comprise the steps:

Step 701: in every path that does not need to seize other LSP, select the poorest link of index.

In selecting every paths in the process of the poorest link of index, for every link in every paths, according to above-mentioned relation formula F (link (u ' v '))=(SB+UB (u ' v '))/RB (u ' v '), calculate the F (link (u ' v ') of every link on every paths) value, more every link F (link (u ' v ')) size is selected F (link (u ' v ')) the maximum link of value is as the poorest link of index;

At more every link F (link (u ' v ')) in the process of value size, if F in described every paths (link (u ' v ')) there are many simultaneously in the maximum link of value, then calculate and F (link (u ' v ') relatively) (RB-SB-UB) value of value maximum link, select (RB-SB-UB) to be worth the link of minimum as the poorest link of index;

At F relatively (link (u ' v ')) in the process of value maximum link (RB-SB-UB) value, if there are many simultaneously in the minimum link of described (RB-SB-UB) value, then in the link of described many (RB-SB-UB) values minimums, select a link at random as the poorest link of index.

Step 702: the link that the index of selecting is the poorest constitutes a set, selects the link of an index optimum in the set that the poorest link of index constitutes.

The set that the poorest link constitutes from index, select in the process of link of index optimum, at first calculate and the F of every link in the set that constitutes of the poorest link of index (link (u ' v ') relatively) value, select F (link (u ' v ')) link of value minimum is as the link of index optimum;

Selecting F (link (u ' v ')) in the process of value smallest link, if there is all equally excellent situation of multilink desired value, then calculate and more simultaneous many F (link (u ' v ')) (RB-SB-UB) value of the minimum link of value, select the link of the link of (RB-SB-UB) value maximum as the index optimum;

In the process of selecting (RB-SB-UB) value maximum link, if there are many simultaneously in the maximum link of described (RB-SB-UB) value, then in the path under many (RB-SB-UB) value maximum link, reject the big link of each self-contained described (RB-SB-UB) value respectively, and execution in

step

701 and 702 once more, until the link of selecting an index optimum; If the maximum link of described (RB-SB-UB) value has only one, then select the link of this link as the index optimum.

Step 703: the link of the index optimum selected as the minimum link of link utilization, is selected the path at this link place.

In addition, in step 702, if in the process of rejecting the big link of each self-contained described (RB-SB-UB) value, the link in certain paths is all rejected, and then selects this paths.

When not needing to seize other LSP, utilization is selected the minimum route method of link utilization based on shown in Figure 7 in not needing to seize the path of other LSP, though can reach the purpose that the present invention improves link utilization and network stabilization, but this method has been ignored following such a case:

For example, existing two not needs that satisfy constraints are seized path candidate path (1), the path (2) of link among other LSP, and this two paths can both provide enough bandwidth for the path that needs are set up.Wherein, path (1) has 10 links, and minimum link utilization is 10%; Path (2) has 2 links, and minimum link utilization is 20%.To set up the LSP of a bandwidth 10M now, according to method shown in Figure 7 since among the path (1) minimum link utilization less than minimum link utilization among the path (2), so select this paths of path (1).But, if select this paths of path (1), the total bandwidth that then will distribute 10M * 10, and this paths of selection path (2), as long as distribute the total bandwidth of 10M * 2 just passable, the total bandwidth of obviously selecting path (2) to distribute is much smaller, selects path (2) also more reasonable.

Based on above-mentioned analysis, when not needing to seize other LSP, the invention provides the method that another selects not need to seize other LSP.As shown in Figure 8, Fig. 8 selects the minimum route method flow chart of number of links for the present invention in not needing to seize the path of other LSP, and this method may further comprise the steps:

Step 801: the quantity of in not needing to seize the path of other LSP, calculating link that every paths comprises.

Step 802:, judge whether the minimum path of number of links has only 1, if then execution in step 803 according to the quantity of the link that every paths comprised that calculates; Otherwise, execution in step 804.

Step 803: select the minimum path of number of links, process ends.

Step 804: if the minimum path of number of links has many simultaneously, then that number of links is minimum path constitutes a set, suppose F (link (uv))=(SB+UB (uv))/RB (uv), wherein, reservation total bandwidth on RB (uv) the expression link link (uv), occupied total bandwidth on UB (uv) the expression link link (uv), SB represents the bandwidth that newly-built LSP is required, according to formula P (path (u))=F (link (u1))+F (link (u2))+... F (link (un)) calculates P (path (the u)) value of every paths in this set, judge whether the minimum path of P (path (u)) value has only 1, if then execution in step 805; Otherwise, execution in step 806.

Step 805: select the minimum path of P (path (u)) value, process ends;

Step 806: in the path of many P (path (u)) value minimum, select a paths at random.

In the present invention embodiment shown in Figure 8,, can between step 801 and step 802, further define the tolerance G of a user to number of links in order to select the minimum path of number of links rapidly.The ascending order of quantity of supposing the link that every paths comprised that step 801 calculates is followed successively by: N1, N2 ..., Nm, wherein m is the quantity in path, reject the n paths from this m paths after, remaining j paths all satisfies G 〉=Nj/N1.Wherein m, n, j are natural number, and n+j=m.Utilize the tolerance G of the user of definition to number of links, can be at first reject such path in not needing to seize the path of link among other LSP: the ratio of number of links and smallest link quantity is greater than the path of the tolerance G of number of links in this path, make step 802 when selecting the minimum path of number of links, the scope of selecting reduces the easier minimum path of number of links of selecting.Such technical scheme is consistent on thinking with technical scheme provided by the invention, should be included within protection scope of the present invention.

In addition, in the present invention embodiment shown in Figure 8, in order more promptly to select the minimum path of number of links, can also be between step 801 and step 802, perhaps behind tolerance G rejecting number of links the path greater than the tolerance G of number of links of the user who utilizes definition to number of links, further to the value of every link load rate F (link (uv)) in this path of path computing that does not need to seize link among other LSP, F (link (uv))=(SB+UB (uv))/RB (uv) wherein, define the tolerance H of a user then to the link load rate, utilize the tolerance H of link load rate to reject the path of link load rate greater than the tolerance H of link load rate, make step 802 when selecting the minimum path of number of links, the scope of selecting reduces the easier minimum path of number of links of selecting.Such technical scheme is consistent on thinking with technical scheme provided by the invention, should be included within protection scope of the present invention.

Above-described specific embodiment; purpose of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the above only is specific embodiments of the invention; be not limited to the present invention; within the spirit and principles in the present invention all, any modification of being made, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims

1, a kind of selection route method is characterized in that, may further comprise the steps:

2, method according to claim 1 is characterized in that, judges whether to exist the path that does not need to seize other LSP to be described in the steps A:

Initial router judges between self and the purpose router whether have the path that available bandwidth resources can both satisfy new business flow needs on the whole links at least.

3, method according to claim 1 is characterized in that, selects a paths to comprise described in the step B in not needing to seize the path of other LSP:

In not needing to seize the path of other LSP, select the path that link utilization is minimum.

4, method according to claim 3 is characterized in that, describedly selects the minimum path of link utilization to comprise in not needing to seize the path of other LSP:

5, method according to claim 4 is characterized in that, described step B1 comprises:

6, method according to claim 5 is characterized in that, there are many simultaneously in the maximum link of F described in the step B12 (link (uv)) value, and this method further comprises:

Calculate and compare (RB-SB-UB) value of F (link (uv)) value maximum link, the link of selecting (RB-SB-UB) value minimum is as the poorest link of index.

7, method according to claim 6 is characterized in that, there are many simultaneously in the minimum link of described (RB-SB-UB) value, and this method further comprises:

In the link of described many (RB-SB-UB) value minimum, select a link at random as the poorest link of index.

8, method according to claim 4 is characterized in that, selects the link of an index optimum to comprise in the set that the poorest link of index constitutes described in the step B2:

Calculate and the size of every link F (link (uv)) value in the set that constitutes of the poorest link of index relatively, selects the link of the link of a F (link (uv)) value minimum as the index optimum.

9, method according to claim 8 is characterized in that, there are many simultaneously in the minimum link of described F (link (uv)) value, and this method further comprises:

Calculate and compare (RB-SB-UB) value of F (link (uv)) value smallest link, select the link of the link of (RB-SB-UB) value maximum as the index optimum.

10, method according to claim 9 is characterized in that, there are many simultaneously in the maximum link of described (RB-SB-UB) value, and this method further comprises:

In the path of described many (RB-SB-UB) value under the maximum link, reject the big link of each self-contained described (RB-SB-UB) value respectively, and execution in step B1 and B2 once more, until the link of selecting an index optimum.

11, method according to claim 10, it is characterized in that, described link in certain paths is all rejected in the process of rejecting the big link of each self-contained described (RB-SB-UB) value, and the path of selecting among the step B3 is the path that described link is all rejected.

12, method according to claim 1 is characterized in that, selects a paths to comprise described in the step B in not needing to seize the path of other LSP:

In not needing to seize the path of other LSP, select the path that number of links is minimum.

13, method according to claim 12 is characterized in that, describedly selects the minimum path of number of links to comprise in not needing to seize the path of other LSP:

14, method according to claim 13 is characterized in that, there are many simultaneously in the minimum path of number of links described in the step B2 ', and this method further comprises:

The path that number of links is minimum constitutes a set, suppose P (path (u))=F (link (u1))+F (link (u2))+... F (link (un)), F (link (uv))=(SB+UB (uv))/RB (uv) wherein, according to formula P (path (u))=F (link (u1))+F (link (u2))+... F (link (un)) calculates P (path (the u)) value of every paths in this set, selects the minimum path of P (path (u)) value.

15, method according to claim 14 is characterized in that, there are many simultaneously in the minimum path of described P (path (u)) value, and this method further comprises:

In the path of described many P (path (u)) value minimum, select a paths at random.

16, method according to claim 1 is characterized in that, described step C comprises:

17, method according to claim 16 is characterized in that, described path is the unicast path of point-to-point, and described step C1 comprises:

18, method according to claim 16 is characterized in that, described path is a multicast path to multiple spot, and described step C1 comprises:

C12 ', suppose the relational expression between E (link (uv)) and the LSP (uvrt), wherein E (link (uv)) represents the equivalent quantity of seizing LSP on certain bar link, LSP (uvrt)=LSPs (uvrt)+LSPM1 (uvrt)+LSPM2 (uvrt)+... + LSPMn (uvrt), the priority level of the last v bar of LSPs (uvrt) expression path u link is the quantity that the clean culture LSP of t is seized for the r bandwidth-level, and the priority level that LSPMn (uvrt) represents the last v bar of path u link is the quantity that the multicast path n of t is seized for the r bandwidth-level; With the relational expression between quantity, priority level, bandwidth-level and described E of multicast group address information substitution (link (uv)) and the LSP (uvrt) of LSP on every link, calculate E (link (the uv)) value of every link;

According to claim 17 or 18 described methods, it is characterized in that 19, there are many simultaneously in the maximum link of E described in step C13 or the C13 ' (link (uv)) value, this method further comprises:

The summation of all LSP quantity of being seized selects all links of being seized LSP quantity summation maximum as the poorest link of index on the link of calculating and more simultaneous many E (link (uv)) value maximum.

20, method according to claim 19 is characterized in that, there are many simultaneously in the link of the summation maximum of the described LSP quantity of being seized, and this method further comprises:

In the link of the summation maximum of the LSP quantity that described many quilts are seized, select a link at random as the poorest link of index.

21, method according to claim 16 is characterized in that, selects the link of an index optimum to comprise in the set that the poorest link of index constitutes described in the step C2:

Calculate and the size of every link E (link (uv)) value in the set that constitutes of the poorest link of index relatively, selects the link of the link of an E (link (uv)) value minimum as the index optimum.

22, method according to claim 21 is characterized in that, there are many simultaneously in the minimum link of described E (link (uv)) value, and this method further comprises:

Calculate also many bar E (link (uv)) value smallest link and seized the size of LSP quantity summation, select a quilt to seize the link of the link of LSP quantity summation minimum as the index optimum.

23, method according to claim 22 is characterized in that, there are many simultaneously in the link of the summation minimum of the described LSP quantity of being seized, and this method further comprises:

In the path under the summation smallest link of the LSP quantity that many quilts are seized, reject the link of the summation minimum of each self-contained described LSP quantity of being seized respectively, and execution in step C1 and C2 once more, until the link of selecting an index optimum.

24, method according to claim 23, it is characterized in that, in the process of described link in the summation minimum of rejecting each self-contained described LSP quantity of being seized, the link in certain paths is all rejected, and the path of selecting among the step C3 is the path that described link is all rejected.