Technical Documentation

Configuring and Verifying One-to-One Backup

The following sections describe the steps you must take to configure and verify one-to-one backup.

  1. Configure One-to-One Backup
  2. Verify One-to-One Backup

Configure One-to-One Backup

The following steps show the commands you must issue to configure a LSP with fast reroute and a primary path. The show command output includes bandwidth and hop limit for your information only. Bandwidth and hop limit are not configured on R1. You can configure bandwidth and hop limit using the bandwidth and hop-limit statements at the [edit protocols mpls lsp lsp-path-name] hierarchy level.

Note: It is not necessary to issue the fast-reroute statement on the transit or egress routers.

Action

To configure one-to-one backup on the ingress router, follow these steps:

  1. In configuration mode, go to the following hierarchy level:
    [edit]user@R1# edit protocols mpls
  2. Configure the LSP:
    [edit protocols mpls]user@R1# set label-switched-path lsp-path-name to address

    For example:

    [edit protocols mpls]user@R1# set label-switched-path r1-to-r5 to 192.168.5.1
  3. Configure one-to-one backup (fast reroute):
    [edit protocols mpls]user@R1# set label-switched-path lsp-path-name fast-reroute

    For example:

    [edit protocols mpls]user@R1# set label-switched-path r1-to-r5 fast-reroute
  4. (Optional) Configure a primary path:
    [edit protocols mpls]user@R1# set label-switched-path lsp-path-name primary primary-name

    For example:

    [edit protocols mpls]user@R1# set label-switched-path r1-to-r5 primary via-r2
  5. (Optional) Configure the primary ERO list:
    [edit protocols mpls]user@R1# set path path-name address loose

    For example:

    [edit protocols mpls]user@R1# set path via-r2 10.0.12.14 loose
  6. Verify and commit the configuration:
    [edit protocols mpls]user@R1# show user@R1# commit

Sample Output

[edit protocols mpls]
user@R1# show  
label-switched-path r1-to-r5 {
    to 192.168.5.1;
    fast-reroute;
    primary via-r2;
    bandwidth  bps; # Bandwidth for the LSP
    hop-limit  number; # Maximum number of routers the LSP can traverse
}
path via-r2 {
    10.0.12.14 loose;
}
[...Output truncated...]

[edit protocols mpls]
user@R1# commit 
commit complete

Meaning

When the fast-reroute statement is configured, the ingress router signals all downstream routers to compute and preestablish a detour path for the LSP, using the Constrained Shortest Path First (CSPF) algorithm on the information in the local router’s traffic engineering database (TED). By default, when the detour path is calculated by CSPF, the detour path inherits the same administrative group constraints (link coloring or resource classes) as the main LSP.


Verify One-to-One Backup

Purpose

You can verify that one-to-one backup is established by examining the ingress router and the other routers in the network.

Action

To verify one-to-one backup, enter the following JUNOS CLI operational mode commands:

user@host> show mpls lsp ingress extensive user@host> show rsvp session

Sample Output

The following sample output is from the ingress router R1 in the network shown in One-to-One Backup Detours:

user@R1> show mpls lsp ingress extensive     
Ingress LSP: 1 sessions

192.168.5.1
  From: 192.168.1.1, State: Up, ActiveRoute: 0, LSPname: r1-to-r5
  ActivePath: via-r2 (primary)
   FastReroute desired
  LoadBalance: Random
  Encoding type: Packet, Switching type: Packet, GPID: IPv4
 *Primary   via-r2           State: Up
    SmartOptimizeTimer: 180
    Computed ERO (S [L] denotes strict [loose] hops): (CSPF metric: 3)
 10.0.12.14 S 10.0.24.2 S 10.0.45.2 S 
     Received RRO  (ProtectionFlag 1=Available 2=InUse 4=B/W 8=Node 10=SoftPreempt):
           10.0.12.14(flag=9) 10.0.24.2(flag=1) 10.0.45.2
     8 May 11 14:51:46 Fast-reroute Detour Up
     7 May 11 14:50:55 Record Route:  10.0.12.14(flag=9) 10.0.24.2(flag=1)  10.0.45.2
    6 May 11 14:50:55 Record Route:  10.0.12.14(flag=9) 10.0.24.2 10.0.45.2
    5 May 11 14:50:52 Selected as active path
    4 May 11 14:50:52 Record Route:  10.0.12.14 10.0.24.2 10.0.45.2
    3 May 11 14:50:52 Up
    2 May 11 14:50:52 Originate Call
    1 May 11 14:50:52 CSPF: computation result accepted
  Created: Thu May 11 14:50:52 2006
Total 1 displayed, Up 1, Down 0

Meaning

The sample output from R1 shows that the FastReroute desired object was included in the Path messages for the LSP, allowing R1 to select the active path for the LSP and establish a detour path to avoid R2.

In line 8, Fast-reroute Detour Up shows that the detour is operational. Lines 6 and 7 indicate that transit routers R2 and R4 have established their detour paths.

R2, 10.0.12.14, includes (flag=9), indicating that node protection is available for the downstream node and link. R4, 10.0.24.2, includes (flag=1), indicating that link protection is available for the next downstream link. In this case, R4 can protect only the downstream link because the node is the egress router R5, which cannot be protected. For more information about flags, see the JUNOS Feature Guide.

The output for the show mpls lsp extensive command does not show the actual path of the detour. To see the actual links used by the detour paths, you must use the show rsvp session ingress detail command.

Sample Output

The following sample output is from the ingress router R1 in the network shown in One-to-One Backup Detours.

user@R1> show rsvp session ingress detail  
Ingress RSVP: 1 sessions

192.168.5.1
  From: 192.168.1.1,  LSPstate: Up,  ActiveRoute: 0
  LSPname: r1-to-r5, LSPpath: Primary
  Suggested label received: -, Suggested label sent: -
  Recovery label received: -, Recovery label sent: 100848
  Resv style: 1 FF, Label in: -, Label out: 100848
  Time left:    -, Since: Thu May 11 14:17:15 2006
  Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
  Port number: sender 1 receiver 9228 protocol 0
   FastReroute desired
  PATH rcvfrom: localclient 
  Adspec: sent MTU 1500
  Path MTU: received 1500
  PATH sentto: 10.0.12.14 (fe-0/1/0.0) 35 pkts
  RESV rcvfrom: 10.0.12.14 (fe-0/1/0.0) 25 pkts
  Explct route: 10.0.12.14 10.0.24.2 10.0.45.2 
  Record route: <self> 10.0.12.14 10.0.24.2 10.0.45.2  
     Detour is Up
    Detour Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
    Detour adspec: sent MTU 1500
    Path MTU: received 1500
    Detour PATH sentto: 10.0.17.14 (fe-0/1/1.0) 23 pkts
    Detour RESV rcvfrom: 10.0.17.14 (fe-0/1/1.0) 20 pkts
     Detour Explct route: 10.0.17.14 10.0.79.2 10.0.59.1 
    Detour Record route: <self> 10.0.17.14 10.0.79.2 10.0.59.1  
    Detour Label out: 100848
Total 1 displayed, Up 1, Down 0

Meaning

The sample output from R1 shows the RSVP session of the main LSP. The detour path is established, Detour is Up. The physical path of the detour is displayed in Detour Explct route. The detour path uses R7 and R9 as transit routers to reach R5, the egress router.

Sample Output

The following sample output is from the first transit router R2 in the network shown in One-to-One Backup Detours:

user@R2> show rsvp session transit detail 
Transit RSVP: 1 sessions

192.168.5.1
  From: 192.168.1.1, LSPstate: Up, ActiveRoute: 1
  LSPname: r1-to-r5, LSPpath: Primary
  Suggested label received: -, Suggested label sent: -
  Recovery label received: -, Recovery label sent: 100448
  Resv style: 1 FF, Label in: 100720, Label out: 100448
  Time left:  126, Since: Wed May 10 16:12:21 2006
  Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
  Port number: sender 5 receiver 9216 protocol 0
   FastReroute desired
  PATH rcvfrom: 10.0.12.13 (fe-0/1/0.0) 173 pkts
  Adspec: received MTU 1500 sent MTU 1500
  PATH sentto: 10.0.24.2 (so-0/0/1.0) 171 pkts
  RESV rcvfrom: 10.0.24.2 (so-0/0/1.0) 169 pkts
  Explct route: 10.0.24.2 10.0.45.2 
  Record route: 10.0.12.13 <self> 10.0.24.2 10.0.45.2  
     Detour is Up
    Detour Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
    Detour adspec: received MTU 1500 sent MTU 1500
    Path MTU: received 1500
    Detour PATH sentto: 10.0.27.2 (so-0/0/3.0) 169 pkts
    Detour RESV rcvfrom: 10.0.27.2 (so-0/0/3.0) 167 pkts
     Detour Explct route: 10.0.27.2 10.0.79.2 10.0.59.1 
    Detour Record route: 10.0.12.13 <self> 10.0.27.2 10.0.79.2 10.0.59.1  
    Detour Label out: 100736
Total 1 displayed, Up 1, Down 0

Meaning

The sample output from R2 shows the detour is established (Detour is Up) and avoids R4, and the link connecting R4 and R5 (10.0.45.2). The detour path is through R7 (10.0.27.2) and R9 (10.0.79.2) to R5 (10.0.59.1), which is different from the explicit route for the detour from R1. R1 has the detour passing through the 10.0.17.14 link on R7, while R1 is using the 10.0.27.2 link. Both detours merge at R9 through the 10.0.79.2 link to R5 (10.0.59.1).

Sample Output

The following sample output is from the second transit router R4 in the network shown in One-to-One Backup Detours:

user@R4> show rsvp session transit detail    
Transit RSVP: 1 sessions

192.168.5.1
  From: 192.168.1.1,  LSPstate: Up, ActiveRoute: 1
   LSPname: r1-to-r5, LSPpath: Primary
  Suggested label received: -, Suggested label sent: -
  Recovery label received: -, Recovery label sent: 3
  Resv style: 1 FF, Label in: 100448, Label out: 3
  Time left:  155, Since: Wed May 10 16:15:38 2006
  Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
  Port number: sender 5 receiver 9216 protocol 0
   FastReroute desired
  PATH rcvfrom: 10.0.24.1 (so-0/0/1.0) 178 pkts
  Adspec: received MTU 1500 sent MTU 1500
  PATH sentto: 10.0.45.2 (so-0/0/2.0) 178 pkts
  RESV rcvfrom: 10.0.45.2 (so-0/0/2.0) 175 pkts
  Explct route: 10.0.45.2 
  Record route: 10.0.12.13 10.0.24.1 <self> 10.0.45.2  
     Detour is Up
    Detour Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
    Detour adspec: received MTU 1500 sent MTU 1500
    Path MTU: received 1500
    Detour PATH sentto: 10.0.49.2 (so-0/0/3.0) 176 pkts
    Detour RESV rcvfrom: 10.0.49.2 (so-0/0/3.0) 175 pkts
     Detour Explct route: 10.0.49.2 10.0.59.1 
     Detour Record route: 10.0.12.13 10.0.24.1 <self> 10.0.49.2 10.0.59.1  
    Detour Label out: 100352
Total 1 displayed, Up 1, Down 0

Meaning

The sample output from R4 shows the detour is established (Detour is Up) and avoids the link connecting R4 and R5 (10.0.45.2). The detour path is through R9 (10.0.49.2) to R5 (10.0.59.1). Some of the information is similar to that found in the output for R1 and R2. However, the explicit route for the detour is different, going through the link connecting R4 and R9 (so-0/0/3 or 10.0.49.2.

Sample Output

The following sample output is from R7, which is used in the detour path in the network shown in One-to-One Backup Detours:

user@R7> show rsvp session transit detail 
Transit RSVP: 1 sessions, 1 detours

192.168.5.1
  From: 192.168.1.1,  LSPstate: Up, ActiveRoute: 1
   LSPname: r1-to-r5, LSPpath: Primary
  Suggested label received: -, Suggested label sent: -
  Recovery label received: -, Recovery label sent: 100368
  Resv style: 1 FF, Label in: 100736, Label out: 100368
  Time left:  135, Since: Wed May 10 16:14:42 2006
  Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
  Port number: sender 5 receiver 9216 protocol 0
   Detour branch from 10.0.27.1, to skip 192.168.4.1, Up
    Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
    Adspec: received MTU 1500 
    Path MTU: received 0
    PATH rcvfrom: 10.0.27.1 (so-0/0/3.0) 179 pkts
    Adspec: received MTU 1500 sent MTU 1500
    PATH sentto: 10.0.79.2 (so-0/0/1.0) 177 pkts
    RESV rcvfrom: 10.0.79.2 (so-0/0/1.0) 179 pkts
    Explct route: 10.0.79.2 10.0.59.1 
     Record route: 10.0.12.13 10.0.27.1 <self> 10.0.79.2 10.0.59.1  
     Label in: 100736, Label out: 100368
   Detour branch from 10.0.17.13, to skip 192.168.2.1, Up
    Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
    Adspec: received MTU 1500 
    Path MTU: received 0
    PATH rcvfrom: 10.0.17.13 (fe-0/1/1.0) 179 pkts
    Adspec: received MTU 1500 
    PATH sentto: 10.0.79.2 (so-0/0/1.0) 0 pkts
    RESV rcvfrom: 10.0.79.2 (so-0/0/1.0) 0 pkts
    Explct route: 10.0.79.2 10.0.59.1 
     Record route: 10.0.17.13 <self> 10.0.79.2 10.0.59.1  
     Label in: 100752, Label out: 100368
Total 1 displayed, Up 1, Down 0

Meaning

The sample output from R7 shows the same information as for a regular transit router used in the primary path of the LSP: the ingress address (192.168.1.1), the egress address (192.168.5.1 ), and the name of the LSP (r1-to-r5). Two detour paths are displayed; the first to avoid R4 (192.168.4.1) and the second to avoid R2 (192.168.2.1). Because R7 is used as a transit router by R2 and R4, R7 can merge the detour paths together as indicated by the identical Label out value (100368) for both detour paths. Whether R7 receives traffic from R4 with a label value of 100736 or from R2 with a label value of 100752, R7 forwards the packet to R5 with a label value of 100368.

Sample Output

The following sample output is from R9, which is a router used in the detour path in the network shown in One-to-One Backup Detours:

user@R9> show rsvp session transit detail 
Transit RSVP: 1 sessions, 1 detours

192.168.5.1
  From: 192.168.1.1, LSPstate: Up, ActiveRoute: 1
  LSPname: r1-to-r5, LSPpath: Primary
  Suggested label received: -, Suggested label sent: -
  Recovery label received: -, Recovery label sent: 3
  Resv style: 1 FF, Label in: 100352, Label out: 3
  Time left:  141, Since: Wed May 10 16:16:40 2006
  Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
  Port number: sender 5 receiver 9216 protocol 0
   Detour branch from 10.0.49.1, to skip 192.168.5.1, Up
    Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
    Adspec: received MTU 1500 
    Path MTU: received 0
    PATH rcvfrom: 10.0.49.1 (so-0/0/3.0) 183 pkts
    Adspec: received MTU 1500 sent MTU 1500
    PATH sentto: 10.0.59.1 (so-0/0/0.0) 182 pkts
    RESV rcvfrom: 10.0.59.1 (so-0/0/0.0) 183 pkts
    Explct route: 10.0.59.1 
     Record route: 10.0.12.13 10.0.24.1 10.0.49.1 <self> 10.0.59.1  
    Label in: 100352, Label out: 3
   Detour branch from 10.0.27.1, to skip 192.168.4.1, Up
    Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
    Adspec: received MTU 1500 
    Path MTU: received 0
   Detour branch from 10.0.17.13, to skip 192.168.2.1, Up
    Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
    Adspec: received MTU 1500 
    Path MTU: received 0
    PATH rcvfrom: 10.0.79.1 (so-0/0/1.0) 181 pkts
    Adspec: received MTU 1500 
    PATH sentto: 10.0.59.1 (so-0/0/0.0) 0 pkts
    RESV rcvfrom: 10.0.59.1 (so-0/0/0.0) 0 pkts
     Explct route: 10.0.59.1 
    Record route: 10.0.12.13 10.0.27.1 10.0.79.1 <self> 10.0.59.1  
     Label in: 100368,  Label out: 3
Total 1 displayed, Up 1, Down 0

Meaning

The sample output from R9 shows that R9 is the penultimate router for the detour path, the explicit route includes only the egress link address (10.0.59.1), and the Label out value (3) indicates that R9 has performed penultimate-hop label popping. Also, the detour branch from 10.0.27.1 does not include path information because R7 has merged the detour paths from R2 and R4. Notice that the Label out value in the detour branch from 10.0.17.13 is 100368, the same value as the Label out value on R7.

Sample Output

The following sample output is from the egress router R5 in the network shown in One-to-One Backup Detours:

user@R5> show rsvp session egress detail 
Egress RSVP: 1 sessions, 1 detours

192.168.5.1
  From: 192.168.1.1, LSPstate: Up, ActiveRoute: 0
  LSPname: r1-to-r5, LSPpath: Primary
  Suggested label received: -, Suggested label sent: -
  Recovery label received: -, Recovery label sent: -
  Resv style: 1 FF, Label in: 3, Label out: -
  Time left:  119, Since: Thu May 11 14:44:31 2006
  Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
  Port number: sender 1 receiver 9230 protocol 0
   FastReroute desired
  PATH rcvfrom: 10.0.45.1 (so-0/0/2.0) 258 pkts
  Adspec: received MTU 1500 
  PATH sentto: localclient
  RESV rcvfrom: localclient 
   Record route: 10.0.12.13 10.0.24.1 10.0.45.1 <self>  
   Detour branch from 10.0.49.1, to skip 192.168.5.1, Up
    Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
    Adspec: received MTU 1500 
    Path MTU: received 0
   Detour branch from 10.0.27.1, to skip 192.168.4.1, Up
    Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
    Adspec: received MTU 1500 
    Path MTU: received 0
   Detour branch from 10.0.17.13, to skip 192.168.2.1, Up
    Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
    Adspec: received MTU 1500 
    Path MTU: received 0
    PATH rcvfrom: 10.0.59.2 (so-0/0/0.0) 254 pkts
    Adspec: received MTU 1500 
    PATH sentto: localclient
    RESV rcvfrom: localclient 
    Record route: 10.0.12.13 10.0.24.1 10.0.49.1 10.0.59.2 <self>  
     Label in: 3, Label out: -
Total 1 displayed, Up 1, Down 0

Meaning

The sample output from R5 shows the main LSP in the Record route field and the detours through the network.


Published: 2010-01-30