Dual CE running HSRP to Dual PE MPLS VPN

Answered Question

Hi there,

I have CEHQ running HSRP to CEA-1 and CEA-2. If the link failure on the FE interfaces CEA-1 , traffic from CEHQ will divert to CEA-2. So far so good at this point of time.

However, on the remote PE (PE3) it seems to be that, traffic got black holes due to Serial link between PE1 still a valid path.

How do I influence this type of scenario if occurs? Any manipulation on HSRP?

PE-CE is running OSPF.

Thanks in advance.

maher

I have this problem too.
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Correct Answer by dodgerfan78 about 9 years 2 days ago

What you need is a way for the CE with the failed LAN interface to pass traffic over to the other CE or another device that is LAN capable.

Put some type of point to point link between CEA1 and CEA2. We use exact same setups where I work. The link between the CE routers is an IBGP connection, and to the PE is EBGP.

This way the CE will always have a route to the LAN: directly connected through Ethernet if that interface is up, or through the IBGP neighbor if the Ethernet interface is down.

It doesn't need to be BGP, it can be any routing protocol - perhaps even a static floating route with a high AD. If CEHQ is on the LAN, then the failed CE couldn't get there anyway because it's LAN interface is down - Unless of course you had a seperate connection for CE-CEHQ :)

-B

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jiangu Sat, 12/08/2007 - 21:01

Do you run OSPF between CEs and CE-HQ? if the link on CEA1 breaks, CEA1 will stop advertising CE-HQ routes to PE1, the PE3 will get HQ routes from PE2, and vice versa. Downside is that if nothing breaks, traffic in-out CE-HQ may traverse different path.

Correct Answer
dodgerfan78 Sun, 12/09/2007 - 09:51

What you need is a way for the CE with the failed LAN interface to pass traffic over to the other CE or another device that is LAN capable.

Put some type of point to point link between CEA1 and CEA2. We use exact same setups where I work. The link between the CE routers is an IBGP connection, and to the PE is EBGP.

This way the CE will always have a route to the LAN: directly connected through Ethernet if that interface is up, or through the IBGP neighbor if the Ethernet interface is down.

It doesn't need to be BGP, it can be any routing protocol - perhaps even a static floating route with a high AD. If CEHQ is on the LAN, then the failed CE couldn't get there anyway because it's LAN interface is down - Unless of course you had a seperate connection for CE-CEHQ :)

-B

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