11-10-2008 01:18 AM - edited 03-04-2019 12:15 AM
Hi,
I have configured the following on untrusted router which is having Primary and back up MPLS link to the 10.51.38.1 ( primary link)
and 10.52.38.1 ( back up link) network .
Scenario
10.50.38.0/24 --Internal network
10.50.38.1 -Router E0 (Default gateway)
10.51.38.0/30- External- Primary MPLS link
10.52.38.0/30 - External- secondary MPLS link
configuration
Interface fa3/0
ip address 10.51.38.2 255.255.255.252
no ip proxy-arp
ip nat outside
ip virtual-reassembly
ip ospf network broadcast
ip ospf cost 1
ip ospf pririty 0
ip ospf mtu-ignore
duplex auto
speed auto
no shut
interface fa3/1
ip address 10.52.38.2 255.255.255.252 --
no ip proxy-arp
ip nat outside
ip virtual-reassembly
ip ospf network broadcast
ip ospf cost 10
ip ospf pririty 0
ip ospf mtu-ignore
duplex auto
speed auto
no shut
router ospf 150
log-adjacency-changes
network 10.50.38.1 0.0.0.0 area 10
network 10.51.38.0 0.0.0.3 area 10
network 10.52.38.0 0.0.0.3 area 10
My question is
1) Does it work ?
2) If yes is this correct method ?
3) what will happen when primary link fail ?
thanks in advance
11-10-2008 01:29 AM
Hello Hashim,
1) if the MPLS service is a L2 service your configuration should work.
You should configure in the same way at the other(s) site(s) so that all of them agree on the primary cloud / link
2) This is a legimitate configuration if you want to use only one link and the other is a cold backup. If you want to use both just let unchanged OSPF costs.
3) when the primary link fails the router will detect failure of the link, the OSPF neighbor will be declared dead within dead-interval seconds, after 5 seconds the SPF is executed, all prefixes are now reached via backup link
the convergence time is up to 46 seconds with default timers settings.
You can speed using :
i) OSPF fast-hellos under second frequency
ii ) or by using BFD (Bidirectional forwarding detection)
Hope to help
Giuseppe
11-10-2008 10:17 PM
thanks Giuseppe, i have to test this.Do you have any other working configuration on this scenario ?
regards,
Hashim
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