JP4422114B2 - Failure effect degree determination method, apparatus and program - Google Patents

Description

  The present invention relates to a failure impact degree determination method, apparatus, and program, and more particularly to FRR (Fast Reroute) and Backup in an MPLS (Multi Protocol Label Switching) network in which RSVP-TE (Resource Reservation Signaling Protocol for Traffic Engineering) operates. The present invention relates to a failure influence degree determination method, apparatus, and program for examining how LSP (Label Switching Path) in which various protection methods such as LSP are set is affected at the time of failure.

  In recent years, RSVP-TE, which enables traffic engineering and fast detour (FRR), has attracted attention in constructing MPLS networks. In RSVP-TE, Explicit Route can be specified in a signaling message. The specification method includes Strict specification that specifies all transit nodes and the route between the specified nodes is the shortest of IGP (Interior Gateway Protocol). There is a Loose designation that follows the route. In addition, it is possible to secure a bandwidth by designating a required bandwidth for each LSP. Therefore, when there is no space for the requested bandwidth on the link on the route determined above, the LSP cannot be set (see, for example, Non-Patent Document 1).

  There are two main types of protection that can bypass the LSP in the event of a failure. Local Repair and Global Repair. Local Repair is a method that bypasses LSP failure parts partially and at high speed, and is also called FRR.

  As shown in Figure 13, FRR has a one-to-one backup that automatically calculates and configures the Detour LSP using the CSPF algorithm to protect all the nodes and links of a single LSP, and a specific link. There is Facility Backup that protects nodes and can bypass multiple tunnels simultaneously. The bypass path of Facility Backup is called Bypass LSP, and there are a method in which a node automatically calculates by a CFPF algorithm and a method in which an Explicit Route is specified in the same way as LSP (for example, see Non-Patent Document 2). In the Detour LSP and Bypass LSP, the node on the LSP that is the starting point of the detour is called PLR (Point of Local Repair), and the node on the LSP that is the end point of the detour is called MP (Merge Point).

  Global Repair is a method of switching to a new LSP between the Ingress-Egress nodes of the LSP. If a spare LSP (Backup LSP) is set in advance or the fault location is in the Loose specified section, the route is recalculated. It is realized by doing. However, even if a route is found by recalculation of the route, it cannot be bypassed if there is no available bandwidth for the requested bandwidth.

In this way, in an RSVP-TE network in which various route settings and detours are set, depending on the combination of the reserved bandwidth of other LSPs, the FRR of each LSP, the backup LSP, etc. How to be affected depends on the LSP. Previously, there was no clear method to measure the impact, so it was difficult to prioritize the countermeasures when a failure occurred, and efficient failure recovery processing by the administrator was not possible. Also, when building RSVP-TE network, there was no clear indicator for designing LSP and protection scheme that would minimize the impact of failure.
RFC3209 RSVP-TE: Extensions to RSVP for LSP Tunnels RFC4090 Fast Reroute Extensions to RSVP-TE for LSP Tunnels

  In the RSVP-TE network, when a different route setting or reserved bandwidth setting is made for each LSP, or when a different protection method is set for each LSP, how to be affected by a link / node failure differs for each LSP. In the event of a failure, it is necessary to perform efficient recovery, such as preferentially disseminating LSPs with a large impact, but there was no means for automatically acquiring the affected LSP and its impact.

  Also, when designing LSP route design and detour routes for protection, it is important to reduce the failure impact level for the entire network, but there is no index that explicitly indicates the failure impact level.

  The present invention has been made in view of the above points. In an RSVP-TE network in which LSPs with various settings are mixed, an LSP that is affected when a certain link node fails is extracted and the degree of influence is determined. It is an object of the present invention to provide a failure impact degree determination method, apparatus, and program that can be performed.

  It is another object of the present invention to provide a failure impact level determination method, apparatus, and program that can be used as parameters in network design by numerically expressing the impact level.

  FIG. 1 is a diagram for explaining the principle of the present invention.

In the present invention (Claim 1), an LSP and an alternative route such as FRR and Backup LSP are set in the MPLS network in which RSVP-TE operates, and information acquisition means, LSP classification means, no influence Failure influence degree determination for determining the influence of an LSP when a failure occurs in a certain link or node in a failure influence degree determination device having an LSP calculation means, an affected LSP calculation means, an influence output means, and a plurality of storage means A method,
The information acquisition means includes topology information representing the connection relationship of each node of the network, individual setting information of LSP groups set in the network, LSP information indicating the usage route and status, and the target of influence determination An information acquisition step (step 1) for acquiring failure location information representing the location information of the failure to be performed;
The LSP classification means refers to the LSP information acquired in the information acquisition step, classifies the LSP group affected by the failure and the LSP group not affected by the failure, and stores the LSP information together with the LSP information in the LSP classification storage means. LSP classification step (step 2) to perform,
The unaffected LSP calculation means acquires the LSP group that is not affected by the failure from the LSP classification storage means, determines that all the influence levels of the individual LSPs are not affected, and stores the influence degrees in the influence degree storage means. No influence LSP calculation step (step 3),
The affected LSP calculation means acquires the LSP group affected by the failure from the LSP classification storage means from the LSP classification storage means, refers to the LSP information and failure location information of the LSP acquired in the information acquisition step, An affected LSP calculation step (step 4) in which the process of determining the new usage route and state and storing the influence degree in the influence degree storage means is performed on the LSPs affected by the failure of all LSP classification storage means; ,
The influence degree output means performs an influence degree output step (step 5) for outputting the influence degree for each LSP stored in the influence degree storage means.

Further, the present invention (Claim 2), when all the LSPs in the LSP information obtained in the information acquisition step (Step 1) are in a normal state,
In the affected LSP calculation step (step 4),
The affected LSP calculation means assumes that the influence degree is smaller as the switching time to the alternative path at the time of failure is shorter, and the influence degree is smaller as the LSP has more alternative paths at the time of failure.

In the present invention (Claim 3), when the LSP in the LSP information obtained in the information acquisition step (Step 1) includes an LSP in a failure state due to reserved bandwidth over or no route,
In the affected LSP calculation step (step 4),
Affected LSP calculation means is the LSP in the failed state due to the reserved bandwidth exceeding due to the occurrence of failure
The impact level when the state changes to the normal state is smaller than the impact level of the unaffected LSP, and the impact level of the normal state LSP is smaller as the switching time to the alternative path at the time of failure is shorter, It is assumed that an LSP having a greater number of alternative paths at the time of failure has a smaller influence.

  FIG. 2 is a principle configuration diagram of the present invention.

According to the present invention (Claim 4), when a failure occurs in a certain link or node in a situation where an LSP and an alternative route such as FRR or Backup LSP are set in the MPLS network in which RSVP-TE operates, A failure impact determination device for determining the impact of LSP,
Topology information representing the connection relationship of each node in the network, individual setting information of LSP groups set in the network, LSP information representing the usage route and status, and location information of the failure subject to impact determination Information acquisition means 110 for acquiring failure location information representing
The LSP classification obtained by referring to the LSP information acquired by the information acquisition unit 110 and classifying into the LSP group affected by the failure and the LSP group not affected by the failure and storing the LSP information together with the LSP information in the LSP classification storage unit 160 Means 120;
An LSP group that is not affected by the failure is acquired from the LSP classification storage unit 160, the influence levels of the individual LSPs are all determined to be unaffected, and the influence level is stored in the influence level storage unit 190. When,
The LSP group affected by the failure is acquired from the LSP classification storage unit 160, the LSP information and the failure location information of the LSP acquired by the information acquisition unit 110 are referred, the influence degree, the new usage route, and the state are determined, and the influence An influential LSP calculation unit 140 that performs the process of storing the degree in the influence degree storage unit 190 on the LSPs affected by all failures in the LSP classification storage unit;
And an influence output means 150 for outputting the influence degree for each LSP stored in the influence degree storage means 190.

In addition, the present invention (Claim 5), in the affected LSP calculation means 140,
When all the LSPs in the LSP information obtained by the information acquisition means are normal,
It is assumed that the influence degree is smaller as the switching time to the alternative path at the time of the failure is shorter, and the influence degree is smaller as the LSP has more alternative paths at the time of the failure.

Further, the present invention (Claim 6), in the affected LSP calculation means 140,
When there is an LSP in the LSP information obtained by the information acquisition means 110 and there is an LSP in a failure state due to reserved bandwidth over or no route,
When a failure occurs and the LSP in the failed state changes to the normal state due to the reserved bandwidth being exceeded, the influence level of the LSP in the normal state is smaller than that of the unaffected LSP. It is assumed that the influence degree is smaller as the switching time is shorter, and the influence degree is smaller as the LSP has more alternative paths at the time of failure.

The present invention (Claim 7) is a failure influence degree determination program that causes a computer to function as the failure influence degree determination device according to any one of Claims 4 to 6.

  As described above, according to the present invention, in an RSVP-TE network in which LSPs having various routes and protection settings are mixed, the influence degree of the LSP when a failure occurs is automatically determined, and Since the degree of influence can be quantified, it is possible to easily determine the restoration priority and the like.

  In addition, in the present invention, the degree of influence when a certain link or node fails is output, but all link nodes on a certain LSP are designated as failure points, and the influence obtained by each calculation is output. By taking the average or total of the degrees, it is possible to obtain the influence degree of the entire LSP. This value can be used as a parameter when designing a network with a small failure influence degree.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 3 shows a configuration of the failure influence degree determination apparatus according to the first embodiment of the present invention.

  The failure influence degree determination apparatus 100 shown in the figure includes an information acquisition unit 110, an LSP classification unit 120, an unaffected LSP calculation unit 130, an affected LSP calculation unit 140, an influence degree output unit 150, an LSP classification storage unit 160, and a calculation completed. An LSP storage unit 170, a reserved bandwidth storage unit 180, and an influence degree storage unit 190 are included.

  The information acquisition unit 110 acquires topology information, LSP information, failure location information, and influence degree calculation parameters from the outside by inputting from an input device or reading from a storage device.

  The LSP classification unit 120 refers to the LSP information and failure location information acquired by the information acquisition unit 110, classifies the LSP into an LSP that is affected by the failure and an LSP that is not affected by the failure, and stores the LSP in the LSP classification storage unit 160. Store.

  The unaffected LSP calculation unit 130 acquires LSPs classified as LSPs that are not affected by the failure from the LSP classification storage unit 160, determines that all the primary LSPs are unaffected, and affects the degree of influence, usage route, and reserved bandwidth. Stored in the storage unit 190, the LSP is stored in the calculated LSP storage unit 170, the reserved bandwidth for each link is calculated and stored in the reserved bandwidth storage unit 180.

  The affected LSP calculation unit 140 acquires the LSP classified into the LSP affected by the failure from the LSP classification storage unit 160, determines the influence level of the LSP, and uses the route newly calculated by the route calculation function, The requested bandwidth is stored in the impact storage unit 190, and the LSP is stored in the calculated LSP storage unit 170. Further, the reserved bandwidth is added to the link through which the LSP passes with reference to the use route and the requested bandwidth, and the reserved bandwidth for each link is stored in the reserved bandwidth storage unit 180.

  The impact level output unit 150 outputs the impact level of the impact level storage unit 190.

  Next, the operation in the above configuration will be described.

  FIG. 4 is a flowchart of the operation in the first embodiment of the present invention.

  Step 101) First, the information acquisition unit 110 acquires topology information representing the connection relationship of each node of the network. The topology information includes the metric value and bandwidth of each link in addition to the connection relationship of each node.

  Step 102) Next, the information acquisition unit 110 acquires the individual setting information of the LSP group set in the network, the LSP information representing the usage route and the state. Here, in the LSP. Information, in addition to the Primary LSP used as the main route, the Detour LSP and Bypass LSP set as the FRR route, and the Backup LSP are handled independently as one LSP. The LSP setting information in the LSP information includes an ID number, an LSP type, an Ingress (PLR) node, an Egress (MP) node, a requested route, a requested bandwidth, and a protection method. In the present embodiment, it is assumed that the LSP state is normal in all LSPs.

  Step 103) Next, the information acquisition unit 110 accepts failure location information representing a failure node or a failure link as a target of influence degree determination.

  Step 104) Next, the information acquisition unit 110 acquires parameters for calculating the influence degree (influence degree calculation parameters). Details of the influence degree calculation parameter will be described later.

  Step 105) Next, the LSP classification unit 120 refers to the LSP information and failure location information acquired by the information acquisition unit 110, and classifies the LSP into an LSP that is affected by the failure and an LSP that is not affected by the failure. Specifically, the affected LSP is an LSP that passes through the failure location, and the LSP that is not affected is an LSP that does not pass through the failure location. LSP information for each LSP is stored in the LSP classification information storage unit 160 for each classification.

  Step 106) The unaffected LSP calculation unit 130 determines that all the LSPs classified as LSPs that are not affected by the failure from the LSP classification information storage unit 160 are unaffected (influence level = 0), and has an effect. The degree of use, the route used, and the reserved bandwidth are stored in the influence degree storage unit 190. LSPs other than the Primary LSP store the usage route and reserved bandwidth in the reserved bandwidth storage unit 180.

  Step 107) The unaffected LSP calculation unit 130 stores the unaffected LSP group in the calculated LSP storage unit 170.

  Step 108) The unaffected LSP calculation unit 130 refers to the use path and the requested bandwidth of each LSP that is not affected, adds the reserved bandwidth to the link through which the LSP passes, and sets the reserved bandwidth for each link as the reserved bandwidth. Save in the storage unit 180. Here, if the topology information first obtained in step 101 includes the reserved bandwidth information for each link that is the sum of the required bandwidths of all LSPs, the requested bandwidth of the LSP that is not affected is Instead of adding, it may be possible to refer to each usage path of the affected LSP and subtract the required bandwidth of the LSP from the link of the usage path.

  Step 109) Next, the affected LSP calculation unit 140 refers to the calculated LSP storage unit 170, extracts one affected LSP that has not been calculated from the LSP classification recording unit 160, and the LSP In the case of Primary LSP, the impact level is determined. Further, when the LSP is other than the Primary LSP, the influence degree is not determined. The determined influence degree, usage route, and requested bandwidth are stored in the influence degree storage unit 190. The processing of the affected LSP calculation unit 140 will be described later.

  Step 110) The LSP for which the influence degree is determined is stored in the calculated LSP storage unit 170.

  Step 111) Referring to the use route and the requested bandwidth, the reserved bandwidth is added to the link through which the LSP passes, and the reserved bandwidth for each link is stored in the reserved bandwidth storage unit 180.

  Steps 109 to 111 are repeated until all affected LSPs are stored in the calculated LSP storage unit 170.

  Step 112) The influence output unit 150 outputs the influence level for each LSP stored in the influence storage 190, and ends the process.

  Next, the operation of determining the influence level in step 109 will be described in detail.

  The degree of influence is such that the shorter the switching time to the alternative path at the time of failure, the smaller the degree of influence, and the lower the degree of influence the LSP with many alternative paths at the time of failure, and it is one of the following eight levels: Determined.

・ Level 1: Detour by FRR, detour to Backup LSP, and route discovery by recalculation of Loose specified section;
・ Level 2: After detour by FRR, detour to Backup LSP;
・ Level 3: After FRR, find route by recalculating Loose specified section;
・ Level 4: Detour to FRR route;
・ Level 5: After detouring to Backup LSP, find route by recalculating Loose designated section;
・ Level 6: Bypass to Backup LSP;
・ Level 7: Route discovery by recalculation of Loose specified section;
Level 8: no route;
FIG. 5 and FIG. 6 are flowcharts of the influence degree determination operation of the affected LSP in the first embodiment of the present invention.

  Step 201) First, the affected LSP calculation unit 140 performs a path calculation between Ingress and Egress according to a request path of the LSP on the topology in a state where the failure part is deleted.

  Step 202) In the Strict designated section, if there is a designated node and a link connecting them, it is determined that there is a route. In the Loose specified section, if there is a route between the specified nodes by the shortest route calculation by IGP (Interior Gateway Protocol), it is determined that there is a route. If there is a route, the process proceeds to step 203; otherwise, the process proceeds to step 207.

  Step 203) When there is a route from Ingress to Egress, the requested bandwidth of the LSP is added to the reserved bandwidth of the reserved bandwidth storage unit 180 in the passing link, and the reserved bandwidth storage unit 180 is referred to Determine the presence or absence of a location. If there is no portion where the reserved bandwidth is exceeded, the routine proceeds to step 204, and if there is, the routine proceeds to step 207.

  Step 204) If there is no reservation overlocation, first, in the LSP before the failure, the FRR is set at the designated failure location, and the Bypass or Detour LSP is not affected in the LSP classification storage unit 160. Whether it is classified as or not. If it is classified, the process proceeds to step 205. If it is not classified, the process proceeds to step 206.

  Step 205) When the FRR is set at the designated location in the LSP before the failure and the Bypass or Detour LSP is classified in the LSP not affected by the LSP classification storage unit 160, It is determined whether a Backup LSP is set for the LSP and the Backup LSP is classified as an unaffected LSP.

  When the Backup LSP is set in the LSP and the Backup LSP is classified as an LSP that is not affected (Step 205, Yes), the influence level is determined as “1”.

  In addition, when the Backup LSP is not set for the LSP or is set, but the Backup LSP is classified as an affected LSP (Step 205, No), the impact level is set to “3”. Is determined.

  Step 206) In the LSP before the failure, the FRR is not set or set in the designated failure location, but the LSP classification storage unit 160 classifies the Bypass or Detour LSP as an affected LSP. If the backup LSP is set in the LSP, the LSP classification storage unit 160 determines whether the backup LSP is classified as an unaffected LSP.

  When the Backup LSP is set for the LSP and the Backup LSP is classified as an LSP that is not affected (Yes at Step 206), the influence level is determined to be “5”.

  In addition, when the Backup LSP is not set in the LSP or is set, but the Backup LSP is classified into the affected LSP in the LSP classification storage unit 160, the influence level is set to “7”. Is determined.

  Step 207) When there is no route from Ingress to Egnres, or when there is a route from Ingress to Egress but there is a reserved bandwidth over location (step 203, Yes), first, the specified failure in the LSP before the failure It is determined whether the FRR is set at the location and the Bypass or Detour LSP is classified as an unaffected LSP in the LSP classification storage unit 160.

  When the FRR is set at the designated failure location in the LSP before the failure and the Bypass or Detour LSP is classified as an unaffected LSP in the LSP classification storage unit 160, (Step 207, Yes), go to step 208; otherwise, go to step 209.

  Step 208) When the Backup LSP is set in the LSP and the Backup LSP is classified as an unaffected LSP (Step 208, Yes), the influence level is determined to be “2”.

  If no Backup LSP is set for the LSP, or if it is set but the Backup LSP is classified as an affected LSP (step 208, No), the impact level is determined to be “4”. .

  Step 209) In the LSP before the failure, the FRR is not set or set in the designated failure location, but the LSP classification storage unit 160 classifies the Bypass or Detour LSP as the affected LSP. If it is determined that the Backup LSP is set in the LSP, it is determined whether or not the Backup LSP is classified as an unaffected LSP. When the Backup LSP is set in the LSP and the Backup LSP is classified as an LSP that is not affected (Yes in Step 209), the influence level is determined as “6”.

  If the Backup LSP is not set in the LSP or is set, but the Backup LSP is classified as an affected LSP, the influence level is determined to be “8”.

After determining the level as described above, the influence degree is determined by a specific numerical value and stored in a memory (not shown). In the present embodiment, the influence degree is represented by an effective communication time T _s . The formula for calculating T _s varies depending on the level and is as follows.

Level 1: T _s = T ₁ P ₀ + T ₂ P ₁ + T ₃ P ₂ + T ₄ P ₃
Level 2: T _s = T ₁ P ₀ + T ₂ P ₁ + T ₄ P ₂
Level 3: T _s = T ₁ P ₀ + T ₃ P ₁ + T ₄ P ₂
Level 4: T _s = T ₁ P ₀ + T ₄ P ₁
Level 5: T _s = T ₂ P ₀ + T ₃ P ₁ + T ₄ P ₂
Level 6: T _s = T ₂ P ₀ + T ₄ P ₁
Level 7: T _s = T ₃ P ₀ + T ₄ P ₁
Level 8: T _s = T ₄ P ₀
Here, T _{1 to} T ₄ , P _{0 to} P ₃ are influence parameters acquired in step 104, T ₁ is a time until detouring by FRR is performed, several ms to several tens ms, and T ₂ is time to detour by Backup is performed, T ₃ is the time to bypass is performed discovered route by recalculation of Loose designated section. T ₂ and T ₃ depend on the failure location, the number of tunnel hops, and the like. T ₄ is a time to be restored to the operator fault point is on the order of a few hours. P ₀ is the probability that the designated location will fail, and P ₁ , P ₂ , and P ₃ are the probability that failures will occur simultaneously on the detour set in the tunnel in addition to the designated failure location. For example, in the case of level 1, P ₁ is the probability that a failure will occur simultaneously on the designated location and the FRR detour, P ₂ is the probability that a failure will occur simultaneously on the designated location, the FRR detour, and the Backup tunnel, and P ₀ > P _1> is a _P 2> _{P 3.} These values also depend on the network topology, the number of detour hops, and the like.

  Further, in the process of storing the determined influence level, usage route, and requested bandwidth in step 108 described above, the usage path of the Primary LSP is stored in the influence level storage unit 190 as follows according to the influence level.

Level 1: New route obtained by route calculation;
• Level 2: Route that excludes the failure location from the LSP usage route before the failure;
Level 3: New route obtained by route calculation;
Level 4: Route that excludes the failure location from the LSP usage route before the failure;
Level 5: New route obtained by route calculation;
Level 6: no route;
Level 7: New route obtained by route calculation;
Level 8: no route;
In the case of a node failure, the route excluding the failure point of level = 2 and level = 4 is a route in which a link to the node at both ends of the failure node and the failure node on the route is removed. Means a route obtained by removing the link on the route. In the case of an LSP other than the Primary LSP, the path calculation between Ingress and Egress is performed according to the LSP request path on the topology in which the failed part is deleted. When there is a route, the new route obtained by route calculation is stored in the influence storage unit 190, and when there is no route, it is stored as no route.

  A specific example of the above operation will be described below.

  The topology used in the following description is shown in FIG. 7, and the LSP information is shown in FIG.

  First, the information acquisition unit 110 acquires topology information. The connection relationship of each node, the metric value of each link, and the bandwidth are as shown in FIG. Next, the information acquisition unit 110 acquires LSP information. In the LSP information example of FIG. 8, seven LSPs are set, and the ID number, LSP type, Ingress (PLR) node, Egress (MP) node, request route, requested bandwidth, protection method, and LSP status LSP information is shown.

  Next, the information acquisition unit 110 acquires failure location information. Assume that a link between the node E and the node H is input as a failure point in this operation example.

Next, the information acquisition unit 110 acquires the influence degree parameters T _{1 to} T ₄ and P _{0 to} P ₃ . In addition, said information acquisition part 110 shall acquire each information by reading from the input from an external input device, or a memory | storage device.

The LSP classification unit 120 refers to the LSP information usage path, classifies the affected LSP (LSP that passes through the fault location) and the LSP that is not affected (LSP that does not pass through the fault location), and stores the LSP classification Stored in the unit 160. In this operation example,
・ LSP affected ... (ID =) 1,2,4
-Unaffected LSP ... (ID =) 3, 5, 6, 7
It becomes.

The unaffected LSP calculation unit 130 determines that all the influence levels of the primary LSP that is not affected are unaffected (level 0, impact level = 0), and stores the impact level, the usage route, and the requested bandwidth in the impact level storage unit 190. To do. In this operation example,
ID = 3, influence level = 0, influence degree = 0, usage route = G: H: i: j, required bandwidth = 10 Mbps:
ID = 5, usage route = H: D: A: E, required bandwidth = 20 Mbps;
ID = 6, usage route = M: N: O, required bandwidth = 10 Mbps;
ID = 7, usage route = D: A: B: F: I: J: O: N, requested bandwidth = 10 Mbps:
It becomes.

  The unaffected LSP calculation unit 130 refers to the use path and requested bandwidth of each LSP that is not affected, adds the reserved bandwidth to the link through which the LSP passes, and sets the reserved bandwidth for each link as the reserved bandwidth storage unit 180. Save to. In this operation example, reserved bandwidth information for each link is not included in the topology information, so newly reserved bandwidth information is created and stored in the reserved bandwidth storage unit 180. The reserved bandwidth information at this stage is shown in FIG. Then, the unaffected LSP calculation unit 130 stores the LSPs with ID = 3, 5, 6, and 7 in the calculated LSP storage unit 170.

  Next, the affected LSP calculation unit 140 acquires, from the LSP classification storage unit 160, LSPs with ID = 1 that are not stored in the calculated LSP storage unit 170 among the affected LSPs.

The affected LSP calculation unit 140 determines the degree of influence of the LSP using the algorithms shown in FIGS. According to the route calculation, the link between the nodes designated as strict is broken, and therefore, there is no route. Although the FRR (Facility Backup) is set for the LSP, the Bypass LSP is not set for the failure link E-> H on the LSP, so the FRR is not set. Since no Backup LSP is set for the LSP, the influence level is determined to be 8. Calculate T _s of the impact level 8 and the impact level, usage route, requested bandwidth,
ID = 1, impact level = 8, impact T _s = T ₄ P ₀ , no use route, requested bandwidth = 10 Mbps
Is stored in the influence storage unit 190. No reserved bandwidth is added because there is no use route. The LSP with ID = 1 is stored in the calculated LSP storage unit 170. Next, the affected LSP calculation unit 140 selects the LSP with ID = 2 that is not stored in the calculated LSP storage unit 170 among the affected LSPs. Obtained from the LSP classification storage unit 160. The degree of influence of the LSP is determined using the algorithms shown in FIGS. According to the route calculation, since the link between the nodes designated as Loose is out of order, a route of D: H: L: M: N is calculated by recalculation of IGP, and there is a route. The requested bandwidth of 10 Mbps is added to the link of the new path to the reserved bandwidth information in the reserved bandwidth storage unit 180 in FIG. As a result, it is determined that there is no reserved bandwidth over location. No FRR is set for the LSP. Since the Backup LSP is set and the Backup LSP with ID = 7 is an LSP that is not affected, it is determined that the impact level is 5. Calculate Ts of influence level 5, influence degree, usage route, requested bandwidth,
ID = 2, influence level = 5, influence level = T _s = T ₂ P ₀ + T ₃ P ₁ + T ₄ P ₂ , use path D: H: L: M: N, required bandwidth = 10 Mbps
Is stored in the influence storage unit 190. The requested bandwidth is added to the link of the use route of the reserved bandwidth information in the reserved bandwidth information storage unit 180. The LSP with ID = 2 is stored in the calculated LSP storage unit 170.

  The same operation is performed even when the LSP with ID = 4 is reached.

Finally, the influence level output unit 150 reads and outputs the influence level from the influence degree storage unit 190, and ends the process. The output information is
ID = 1, impact level = 8, impact = T _s = T ₄ P ₀
ID = 2, influence level = 5, influence = T _s = T ₂ P ₀ + T ₃ P ₁ + T ₄ P ₂
ID = 3, impact level = 0, impact = T _s = 0
ID = 4, impact level = 3, impact = T _s = T ₁ P ₀ + T ₃ P ₁ + T ₄ P2 ₂
It becomes.

  According to the first embodiment, it is possible to quantitatively determine how a normal LSP is affected by a failure from the viewpoint of communication time. Further, it is possible to divide the degree of influence into fine levels, assuming that a failure other than the designated location occurs.

[Second Embodiment]
The configuration of the failure impact degree determination apparatus in the present embodiment is the same as the configuration of FIG. 3 in the first embodiment.

  10 and 11 are flowcharts of operations in the second embodiment of the present invention.

  Step 301) The information acquisition unit 110 acquires topology information representing a connection relation of each node of the network. The topology information includes the metric value and bandwidth of each link in addition to the connection relationship of each node.

  Step 302) The information acquisition unit 110 acquires the LSP group set in the network. Here, in the LSP information, in addition to the Primary LSP used as the main route, the Detour LSP, the Bypass LSP, and the Backup LSP set as the FRR route are handled independently as one LSP. The LSP setting information in the LSP information includes an ID number, an LSP type, an Ingress (PLR) node, an Egress (MP) node, a requested route, a requested bandwidth, and a protection method. In the present embodiment, it is assumed that there are three types of LSP states: “normal”, “failure without path”, and “failure due to bandwidth over”.

  Step 303) The information acquisition unit 110 accepts failure location information representing a failure node or a failure link as a target of influence degree determination.

  Step 304) Next, the information acquisition unit 110 acquires parameter information (influence calculation parameter) for calculating the influence. The details of the influence calculation parameter are the same as those in the first embodiment. In addition, the information acquisition part 110 in said step 301-304 shall acquire each information from the input from an input device, or a memory | storage device.

  Step 304) The LSP classification unit 120 refers to the LSP information and the failure location information, and classifies the LSP into an LSP that is affected by the failure and an LSP that is not affected by the failure. Specifically, the affected LSPs are “normal LSPs that pass through the failed part” and “all LSPs that are in a failed state due to over-band”, and the LSPs that are not affected are “normal LSPs that do not pass through the failed part” And “all LSPs in a failed state without a route”. For each classification, the LSP information for each LSP is stored in the LSP classification storage unit 160.

  Step 306) The unaffected LSP calculation unit 130 acquires an LSP that is not affected by the failure from the LSP classification storage unit 160. Of the LSPs classified as LSPs that are not affected by the failure, all the primary LSPs are determined to have no influence (impact degree = 0), and the influence degree, the use route, and the reserved bandwidth are stored in the influence degree storage unit 190. The LSPs other than the Primary LSP store the usage route and the reserved bandwidth in the influence storage unit 190, and store the reserved bandwidth in the reserved bandwidth storage unit 180.

  Step 307) The unaffected LSP calculation unit 130 stores the LSP group that is not affected in the calculated LSP storage unit 170.

  Step 308) The unaffected LSP calculation unit 130 refers to the use path and the requested bandwidth of each LSP that is not affected, adds the reserved bandwidth to the link through which the LSP of the reserved bandwidth storage unit 180 passes, Are reserved in the reserved bandwidth storage unit 180. Here, if the topology information acquired first includes the reserved bandwidth information for each link, which is the sum of the required bandwidths of all LSPs, the required bandwidth of the LSP that is not affected is added. Instead, it may be possible to refer to each usage path of the affected LSP and subtract the required bandwidth of the LSP from the link of the usage path.

  Step 309) The affected LSP calculation unit 140 refers to the calculated LSP storage unit 170 with the LSPs in the normal state that pass through the failure location among the affected LSP groups, and selects the LSPs that have not been calculated yet. If one is acquired from the LSP classification storage unit 160 and the LSP is a Primary LSP, the degree of influence is determined. The determination method of the influence level and the influence degree is the same as that of the first embodiment.

  If the LSP is an LSP other than the Primary LSP, the influence level is not determined and the process proceeds to the next step.

  The determined influence degree, use route, and requested bandwidth are stored in the influence degree storage unit 190. The storage method is the same as in the first embodiment.

  Step 310) The affected LSP calculation unit 140 stores the LSP in the calculated LSP storage unit 170.

  Step 311) The affected LSP calculation unit 140 refers to the acquired use route and the requested bandwidth, adds the reserved bandwidth to the link through which the LSP of the reserved bandwidth storage unit 180 passes, and sets the reserved bandwidth for each link as the reserved bandwidth storage unit. Stored in 180.

  Among the affected LSPs, until all the normal LSPs that pass through the failure location are stored in the calculated LSP storage unit 170, the influence level determination of the affected LSPs (step 309) to the reserved bandwidth calculation The storage process (step 311) is repeated.

Step 312) The affected LSP calculation unit 140 refers to the calculated LSP recording means in the LSP group that is affected and is in an unsuccessful state due to the band over, and determines one LSP that has not been calculated yet. If the LSP is obtained from the classification storage unit 160 and the LSP is a Primary LSP, the degree of influence is determined. On the topology with the fault location deleted, route calculation is performed according to the LSP request route. If there is a route, add the requested bandwidth of the LSP to the passing link and determine whether there is a reserved bandwidth excess location. . When there is no reserved bandwidth over location,
・ Influence level = -1
・ Influence degree T _s = T ₅ (T ₅ <0)
By determining that, T ₅ is one of influence calculation parameters acquired in step 304. If there is a reserved bandwidth over or no route,
・ Effect level = 0
・ Influence degree = 0
Is determined.

  If the LSP is an LSP other than the Primary LSP, the influence level is not determined and the process proceeds to the next step.

  The determined influence degree, use route, and requested bandwidth are stored in the influence degree storage unit 190. Here, the route used is calculated according to the LSP required route on the topology with the fault location deleted. If there is a route, the new route obtained by the route calculation is saved and the route without the route is saved. In such a case, the no path and influence degree storage unit 190 is stored.

  Step 313) The affected LSP calculation unit 140 stores the LSP in the calculated LSP storage unit 170.

  Step 314) The affected LSP calculation unit 140 refers to the use route and the requested bandwidth, adds the reserved bandwidth to the link through which the LSP passes, and stores the reserved bandwidth for each link in the reserved bandwidth storage unit 180.

  From the affected LSPs, all the LSPs that are in a failed state due to bandwidth over are stored in the calculated LSP storage unit 170 until the impact level of the affected LSP is determined (step 312) to calculate / save reserved bandwidth. This process (step 314) is repeated.

  Step 315) Finally, the influence level for each LSP is output and the process is terminated.

  A specific example of the above operation will be described below.

  The topology used below is shown in FIG. 7, and the LSP information is shown in FIG.

  First, the information acquisition unit 110 topology information is acquired. The connection relationship of each node, the metric value and the bandwidth of each link are as shown in FIG.

  Next, the information acquisition unit 110 acquires LSP information. In the example of FIG. 12, seven LSPs are set, and the ID number, LSP type, Ingress (PLR) node, Egress3MP) node, request route, required bandwidth, protection method, and LSP status are as shown in FIG. is there.

  Next, the information acquisition unit 110 acquires failure location information. Assume that a link between the node E and the node H is input as a failure point in this operation example.

Next, the information acquisition unit 110 acquires influence calculation parameters T _{1 to} T ₅ and P _{0 to} P ₃ .

Referring to the LSP information usage route, it is classified into LSPs that are affected (LSP that passes through the fault location) and LSPs that are not affected (LSP that does not pass through the fault location). In this operation example,
Affected LSP (LSP in normal state passing through the fault location) ... (ID =) 1, 2;
Affected LSP (LSP in failed state due to bandwidth over) ... (ID =) 4;
-LSP that is not affected (LSP in a normal state that does not pass through the failure location) ... (ID =) 3, 5, 6, 7;
It becomes.

The influence levels of the primary LSP that are not affected are all determined to have no influence (level = 0), and the influence degree, the use route, and the requested bandwidth are stored in the influence degree storage unit 190. In this operation example,
ID = 3, influence level = 0, influence degree = 0, usage route = G: H: I: J, requested bandwidth = 10 Mbps:
ID = 5, usage route = H: D: A: E, required bandwidth = 20 Mbps:
ID = 6, usage route = M: N: O, required bandwidth = 10 Mbps:
ID = 7, usage route = D: A: B: F: I: J: O: N, requested bandwidth = 10 Mbps:
It becomes.

  The unaffected LSP calculation unit 130 refers to the LSP usage path and requested bandwidth stored in the LSP classification storage unit 160, and adds the reserved bandwidth to the link through which the LSP passes. Each reserved bandwidth is stored in the reserved bandwidth storage unit 180. In this operation example, reserved bandwidth information for each link is not included in the topology information, and therefore reserved bandwidth information is newly created in the reserved bandwidth information storage unit 180. The reserved bandwidth information at this stage is shown in FIG. The LSPs with ID = 3, 5, 6, 7 are stored in the calculated LSP storage unit 170.

  Next, the affected LSP calculation unit 140 is a normal LSP that passes through the failure location among the LSPs affected by the LSP classification storage unit 160, and the ID = 1 that is not stored in the calculated LSP storage unit 170 Get an LSP.

The affected LSP calculation unit 140 determines the degree of influence of the LSP using the algorithms shown in FIGS. According to the route calculation, there is no route because the link between nodes designated as strict is broken. Although the FRR (Facility Backup) is set for the LSP, the Bypass LSP is not set for the failure link E-> H on the LSP, so the FRR is not set. Since no Backup LSP is set for the LSP, the influence level is determined to be 8. Ts of the influence level 8 is calculated, the influence degree, the use route, and the requested bandwidth. ID = 1, the influence level = 8, the influence = T _s = T ₄ P ₀ , the use route is not present, and the requested bandwidth = 50 Mbps:
Is stored in the influence storage unit 190.

Next, the affected LSP calculation unit 140 is a normal state LSP that passes through the failure location among the affected LSPs from the LSP classification storage unit 160, and is not stored in the calculated LSP storage unit 170 = 2. Get the LSP. The degree of influence of the LSP is determined using the algorithms shown in FIGS. According to the route calculation, since the link between the nodes designated as Loose is out of order, the route of D: H: L: M: N is calculated by the recalculation of IGP, and there is a route. The requested bandwidth of 10 Mbps is added to the new route link to the reserved bandwidth information in FIG. As a result, it is determined that there is no reserved bandwidth over location. No FRR is set for the LSP. Since the Backup LSP is set and the Backup LSP with ID = 7 is an LSP that is not affected, it is determined that the impact level is 5. T _s of the influence level 5 is calculated, the influence degree, the use route, and the required bandwidth. ID = 2, the influence level = 5, the influence degree = T _s = T ₂ P ₀ + T ₃ P ₁ + T ₄ P ₂ , use Path = D: H: L: M: N, requested bandwidth = 10 Mbps:
Are stored in the influence storage unit 190. The requested bandwidth is added to the link of the use route in the reserved bandwidth information and stored in the reserved bandwidth storage unit 180, and the LSP with ID = 2 is stored in the calculated LSP storage unit 170.

Next, the affected LSP calculation unit 140 selects an LSP with ID = 4 which is an LSP that is in a failed state due to bandwidth over and is not stored in the calculated LSP storage unit 170 among the LSPs affected by the LSP classification storage unit 160. get. In the route calculation, it is determined that there is a route, and since the LSP with ID = 1 has failed, it is determined in the reserved bandwidth calculation that there is no reserved bandwidth over location, and therefore the influence level is determined to be -1. Calculate T _s of the influence level −1, the influence degree, the use route, the requested bandwidth,
ID = 4, impact level = −1, impact = T _s = T ₅ , usage route = K: L: M: O, required bandwidth = 60 Mbps
Save. The requested bandwidth is added to the link of the use route in the reserved bandwidth information and stored in the reserved bandwidth storage unit 180. The LSP with ID = 4 is stored in the calculated LSP storage unit 170.

Finally, the impact level is output and the process is terminated. The output information is
ID = 1, impact level = 8, impact = T _s = T ₄ P ₀
ID = 2, influence level = 5, influence = T _s = T ₂ P ₀ + T ₃ P ₁ + T ₄ P ₂
ID = 3, impact level = 0, impact = T _s = 0
ID = 4, impact level = −1, impact = T _s = T ₅
It becomes.

  According to the second embodiment described above, the LSP in the failed state among the LSPs that have already been set due to the reserved bandwidth being exceeded, and the normal LSP becomes the failed state due to the failure. It is possible to simulate the actual RSVP-TE network operation of transition, and the LSP can be explicitly extracted by taking a negative value of the influence degree.

  The operations of the first and second embodiments described above can be constructed as a program and installed in a computer used as a failure impact degree determination device for execution, or distributed via a network. is there.

  Further, the constructed program can be stored in a computer-readable disk device or a portable storage medium such as a CD-ROM, installed in a computer, executed, or distributed.

  The present invention is not limited to the above-described embodiment, and various modifications and applications can be made within the scope of the claims.

  The present invention is applicable to a technique for determining the degree of influence of an LSP when a failure occurs in an RSVP-TE network in which LSPs having various paths and protection settings are mixed.

It is a figure for demonstrating the principle of this invention. It is a principle block diagram of this invention. It is a block diagram of the failure influence degree determination apparatus in the 1st Embodiment of this invention. It is a flowchart of the operation | movement in the 1st Embodiment of this invention. It is a flowchart (the 1) of the influence determination operation | movement of LSP which receives in the 1st Embodiment of this invention. It is a flowchart (the 2) of influence degree determination operation | movement of LSP which receives in the 1st Embodiment of this invention. It is a figure which shows the topology utilized in the operation example in the 1st and 2nd embodiment of this invention. It is an example of the LSP information utilized in the operation example in 1st Embodiment of this invention. It is an example of the reserved bandwidth of each link at the time of adding the reserved bandwidth of LSP which is not influenced in the operation example of the 1st and 2nd embodiment of this invention. It is a flowchart (the 1) of the operation | movement in the 2nd Embodiment of this invention. It is a flowchart (the 2) of the operation | movement in the 2nd Embodiment of this invention. It is an example of the LSP information utilized in the operation example in the 2nd Embodiment of this invention. FFR classification.

Explanation of symbols

100 failure influence determination apparatus 110 information acquisition means, information acquisition section 120 LSP classification means, LSP classification section 130 unaffected LSP calculation means, unaffected LSP calculation section 140 affected LSP calculation means, affected LSP calculation section 150 influence degree output means , Influence output unit 160 LSP classification storage means, LSP classification recording section 170 calculated LSP storage section 180 reserved bandwidth storage section 190 influence degree storage means, influence degree storage section

Claims (7)

LSP (Label Switched Path) is set in the MPLS (Multi Protocol Label Switching) network that operates Resource Reservation Signaling Protocol for Traffic Engineering (RSVP-TE), and alternative routes such as FRR (Fast Reroute) and Backup LSP are set in the LSP. Failure in a certain link or node in a failure influence degree determination apparatus having information acquisition means, LSP classification means, no influence LSP calculation means, influence LSP calculation means, influence degree output means, and a plurality of storage means It is a failure influence degree determination method for determining the influence of LSP when an error occurs,
The information acquisition means includes topology information representing the connection relationship of each node of the network, individual setting information of LSP groups set in the network, LSP information indicating the usage route and state, and the target of influence determination An information acquisition step for acquiring failure location information representing the location information of the failure, and
The LSP classification means refers to the LSP information acquired in the information acquisition step, classifies the LSP group affected by the failure and the LSP group not affected by the failure, and stores the LSP classification for each classification together with the LSP information. LSP classification step for storing in the means;
The unaffected LSP calculation means acquires the LSP group that is not affected by the failure from the LSP classification storage means, determines that all the influence levels of the individual LSPs are not affected, and stores the influence degrees in the influence degree storage means. LSP calculation step with no effect to
The affected LSP calculation means acquires from the LSP classification storage means the LSP group affected by the failure from the LSP classification storage means, and refers to the LSP information and failure location information of the LSP acquired in the information acquisition step. The affected LSP calculation is performed for the LSP that is affected by the failure of all the LSP classification storage means, and determines the influence degree, the new usage route, and the state, and stores the influence degree in the influence degree storage means. Steps,
The impact output means outputs an impact level for each LSP stored in the impact level storage means; and
A failure impact determination method characterized by: When all the LSPs in the LSP information obtained in the information acquisition step are in a normal state,
In the affected LSP calculation step,
The affected LSP calculation means, the impact degree is small as the switching time to the alternative path at the time of failure is short, and the influence degree is small as the LSP where there are many alternative paths at the time of failure,
Failure effect degree determination method according to claim 1, wherein. In the LSP in the LSP information obtained in the information acquisition step, when there is a failed LSP due to reserved bandwidth over or no route,
In the affected LSP calculation step,
The affected LSP calculation means is an LSP in a failed state due to a reserved bandwidth exceeding due to a failure.
The impact level when the state changes to the normal state is smaller than the impact level of the unaffected LSP, and the impact level of the normal state LSP is smaller as the switching time to the alternative path at the time of failure is shorter, LSP with more alternative routes at the time of failure is assumed to have a smaller impact.
Failure effect degree determination method according to claim 1, wherein. LSP (Label Switched Path) is set in the MPLS (Multi Protocol Label Switching) network that operates Resource Reservation Signaling Protocol for Traffic Engineering (RSVP-TE), and alternative routes such as FRR (Fast Reroute) and Backup LSP are set in the LSP. A failure impact level determination device that determines the impact of an LSP when a failure occurs in a certain link or node,
Topology information representing the connection relationship of each node in the network, individual setting information of LSP groups set in the network, LSP information representing the usage route and status, and location information of the failure subject to impact determination Information acquisition means for acquiring failure location information representing,
LSP classification that refers to the LSP information acquired by the information acquisition means, classifies the LSP group affected by the failure and the LSP group not affected by the failure, and stores the LSP information together with the LSP information in the LSP classification storage means Means,
An LSP group that is not affected by a failure is acquired from the LSP classification storage unit, the influence level of each LSP is determined to be all unaffected, and the influence level LSP calculation unit that stores the degree of influence in the impact level storage unit;
The LSP group affected by the failure is acquired from the LSP classification storage means from the LSP classification storage means, and the LSP information and failure location information of the LSP acquired by the information acquisition means is referred to, the degree of influence, the new usage route, and the state And having the influence stored in the influence storage means for the LSP affected by all the faults in the LSP classification storage means, an affected LSP calculation means,
An impact output means for outputting the impact for each LSP stored in the impact storage means;
A failure influence degree determination device characterized by comprising: The affected LSP calculating means is:
When all LSPs in the LSP information obtained in the information acquisition means are in a normal state,
The shorter the switching time to the alternative route at the time of failure, the smaller the impact, and the smaller the impact the LSP with many alternative routes at the time of failure,
The failure influence degree determination apparatus according to claim 4. The affected LSP calculating means is:
In the LSP in the LSP information obtained in the information acquisition means, if there is a failed LSP due to reserved bandwidth over or no route,
When a failure occurs and the LSP in the failed state changes to the normal state due to the reserved bandwidth being exceeded, the influence level of the LSP in the normal state is smaller than that of the unaffected LSP. As the switching time is shorter, the degree of influence is small, and the degree of influence is small for LSPs with many alternative paths at the time of failure.
The failure influence degree determination apparatus according to claim 4. Computer
A failure influence degree determination program that functions as the failure influence degree determination device according to any one of claims 4 to 6.

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