145
Hop 3 40.1.1.1
Hop 4 40.1.1.2
Hop 5 3.3.3.9
# Execute the tracert command to draw the picture of the path that a packet must travel to reach
the tunnel destination.
[SwitchA] tracert –a 1.1.1.9 3.3.3.9
traceroute to 3.3.3.9(3.3.3.9) 30 hops max,40 bytes packet
1 10.1.1.2 25 ms 30.1.1.2 25 ms 10.1.1.2 25 ms
2 40.1.1.2 45 ms 20.1.1.2 29 ms 40.1.1.2 54 ms
The output shows that the current LSP traverses Switch B but not Switch D.
# Shut down VLAN-interface 2 on Switch B. Execute the tracert command on Switch A to draw the
path to the tunnel destination.
[SwitchA] tracert –a 1.1.1.9 3.3.3.9
traceroute to 3.3.3.9(3.3.3.9) 30 hops max,40 bytes packet
1 30.1.1.2 28 ms 27 ms 23 ms
2 40.1.1.2 50 ms 50 ms 49 ms
The output shows that the LSP is re-routed to traverse Switch D.
# Execute the display mpls te tunnel command on Switch A. You can see that only the tunnel
traversing Switch D is present.
[SwitchA] display mpls te tunnel
LSP-Id Destination In/Out-If Name
1.1.1.9:2054 3.3.3.9 -/Vlan4 Tunnel1
Configuring ordinary CR-LSP backup is almost the same as configuring hot CR-LSP backup except
that you replace the mpls te backup hot-standby command with the mpls te backup ordinary
command. Unlike in hot CR-LSP backup where a secondary tunnel is created immediately upon
creation of a primary tunnel, in ordinary CR-LSP backup, a secondary CR-LSP is created only after
the primary LSP goes down.
6. Direct traffic to the MPLS TE tunnel:
# Create a static route to direct traffic to the MPLS TE tunnel.
[SwitchA] ip route-static 20.1.1.2 24 tunnel 1 preference 1
# Execute the display ip routing-table command on Switch A. You can see a static route entry with
Tunnel1 as the outgoing interface.
FRR configuration example
Network requirements
On a primary LSP Switch A—Switch B—Switch C—Switch D, use FRR to protect the link Switch B—Switch
C.
Create a bypass LSP that traverses the path Switch B—Switch E—Switch C. Switch B is the PLR and Switch
C is the MP.
Explicitly route the primary TE tunnel and the bypass TE tunnel with the signaling protocol being RSVP-TE.
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