MPLS TE Example

Introduction

This page provides an example configuration for MPLS TE FRR Link Protection.

MPLS TE Example

mpls-te-frr-tunnels.jpg
  • The green path is for Tunnel36. Tunnel36 is used for TE between R2 PE and R8 PE.
  • The red path is for Tunnel46 (link protection for R3.Gi3/0 and R6.Gi1/0).
  • The link between R3 and R6 is protected with FRR.
  • The GNS3 file of this setup is MPLS-TE-Wiki.zip

PEs Router Configuration

R2

R8

P Router Configuration

R3

R6

Normal Operation

R1#traceroute 9.9.9.9 source loop0
Type escape sequence to abort.
Tracing the route to 9.9.9.9
VRF info: (vrf in name/id, vrf out name/id)
  1 10.1.12.2 68 msec 48 msec 52 msec
  2 10.1.23.3 [MPLS: Labels 3001/8011 Exp 0] 124 msec 128 msec 92 msec
  3 10.1.36.6 [MPLS: Labels 6002/8011 Exp 0] 116 msec 124 msec 112 msec
  4 10.1.89.8 [MPLS: Label 8011 Exp 0] 88 msec 124 msec 100 msec
  5 10.1.89.9 128 msec *  104 msec
R2#sh mpls traffic-eng tunnels tunnel 36

Name: R2_t36                              (Tunnel36) Destination: 8.8.8.8
  Status:
    Admin: up         Oper: up     Path: valid       Signalling: connected
    path option 1, type explicit R3R6 (Basis for Setup, path weight 3)        
    path option 2, type dynamic

  Config Parameters:
    Bandwidth: 0        kbps (Global)  Priority: 7  7   Affinity: 0x0/0xFFFF
    Metric Type: TE (default)
    AutoRoute: enabled  LockDown: disabled Loadshare: 0 [0] bw-based
    auto-bw: disabled
  Active Path Option Parameters:
    State: explicit path option 1 is active                            <--option 1 used
    BandwidthOverride: disabled  LockDown: disabled  Verbatim: disabled

  InLabel  :  -
  OutLabel : GigabitEthernet2/0, 3001
  Next Hop : 10.1.23.3
  RSVP Signalling Info:
       Src 2.2.2.2, Dst 8.8.8.8, Tun_Id 36, Tun_Instance 2265
    RSVP Path Info:
      My Address: 10.1.23.2
      Explicit Route: 10.1.23.3 10.1.36.3 10.1.36.6 10.1.68.6            
                      10.1.68.8 8.8.8.8
      Record   Route:   NONE
      Tspec: ave rate=0 kbits, burst=1000 bytes, peak rate=0 kbits
    RSVP Resv Info:
      Record   Route:  3.3.3.3(3001) 6.6.6.6(6002)
                       8.8.8.8(3)
      Fspec: ave rate=0 kbits, burst=1000 bytes, peak rate=0 kbits
  Shortest Unconstrained Path Info:
    Path Weight: 2 (TE)
    Explicit Route: 10.1.24.2 10.1.24.4 10.1.48.4 10.1.48.8
                    8.8.8.8
  History:
    Tunnel:
      Time since created: 1 days, 19 hours, 23 minutes
      Time since path change: 23 hours, 30 minutes
      Number of LSP IDs (Tun_Instances) used: 2265
    Current LSP: [ID: 2265]
      Uptime: 23 hours, 30 minutes
    Prior LSP: [ID: 2264]
      ID: path option unknown
      Removal Trigger: tunnel shutdown
R3#sh mpls traffic-eng fast-reroute database
P2P Headend FRR information:
Protected tunnel               In-label Out intf/label   FRR intf/label   Status
---------------------------    -------- --------------   --------------   ------

P2P LSP midpoint frr information:
LSP identifier                 In-label Out intf/label   FRR intf/label   Status
---------------------------    -------- --------------   --------------   ------
2.2.2.2 36 [2265]              3001     Gi3/0:6002       Tu46:6002        ready

P2MP Sub-LSP FRR information:
*Sub-LSP identifier
src_lspid[subid]->dst_tunid    In-label Out intf/label   FRR intf/label   Status
---------------------------    -------- --------------   --------------   ------

FRR Operation

  • Test test the failover, I had to shutdown R3.Gi3/0 AND R6.Gi1/0 since GNS3 can't detect the interface going down.
  • During the FRR and while the PEs are looking for another path (if the dynamic option is used), backup tunnel46 is used. R3 imposes a 3rd label to bypass the link failure.
R1#traceroute 9.9.9.9 source loop0
Type escape sequence to abort.
Tracing the route to 9.9.9.9
VRF info: (vrf in name/id, vrf out name/id)
  1 10.1.12.2 68 msec 60 msec 60 msec
  2 10.1.23.3 [MPLS: Labels 3004/8011 Exp 0] 180 msec 128 msec 144 msec
  3 10.1.34.4 [MPLS: Labels 4005/6000/8011 Exp 0] 168 msec 156 msec 148 msec
  4 10.1.46.6 [MPLS: Labels 6000/8011 Exp 0] 248 msec 132 msec 196 msec
  5 10.1.89.8 [MPLS: Label 8011 Exp 0] 192 msec 272 msec 184 msec
  6 10.1.89.9 176 msec *  172 msec
R2#und all
All possible debugging has been turned off
R2#sh mpls traffic-eng tunnels tunnel 36

Name: R2_t36                              (Tunnel36) Destination: 8.8.8.8
  Status:
    Admin: up         Oper: up     Path: valid       Signalling: connected
    path option 1, type explicit R3R6 (Basis for Setup, path weight 3)
        Change in required resources detected: reroute pending        <---FRR active, looking for another path.
        Currently Signalled Parameters:
          Bandwidth: 0        kbps (Global)  Priority: 7  7   Affinity: 0x0/0xFFFF
          Metric Type: TE (default)

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