AD 200 route preferred over AD 90

[wintermute000]

Yes read that right.
Can anyone explain the below output?


In a nutshell, I got into a situation where a EIGRPv6 route was being overridden by a vpnv6 route via MP-BGP.
The MP-BGP route is via iBGP with AD200 - why would it take precedence?
In particular, 'backup via' - what's that all about? FWIW I do NOT have fast-reroute/LFA turned on.





R2#show ipv6 route vrf CustA 2001:10:245:2::8/127
Routing entry for 2001:10:245:2::8/127
  Known via "bgp 101", distance 200, metric 1536000, type internal
  Redistributing via eigrp 925
  Backup from "eigrp 925 [90]"
  Route count is 1/1, share count 0
  Routing paths:
    122.1.1.1%default indirectly connected
      MPLS label: 37
      Last updated 00:03:42 ago


Followup: I got rid of this via redistributing the EIGRP route into BGP as well. This meant the local weight 100 route took precedence over the iBGP learnt route, but as soon as that happens, the EIGRPv6 route goes back into the RiB (as you'd expect). Are VPNvX routes treated differently?




EDIT::: OMG its this stuff. As the MP-BGP route is imported from same EIGRPv6 ASN, the extended communities are passed and the router does a metric to community aka the metric comparison i.e. ignores the AD. GAH!
http://blog.ine.com/2010/07/19/mpls-and-eigrp-going-the-distance-admin-distance/

[deanwebb]

So, what you're saying is... it's not the firewall.

[srg]

So, what you're saying is... it's not the firewall.

it's always the firewall >;P

[deanwebb]

So, what you're saying is... it's not the firewall.

it's always the firewall >;P

It's always the LOAD BALANCER.

[that1guy15]

Yup, you beat me to the punch wintermute000.

Drill into your head that anytime EIGRP and BGP work together BGP will pass EIGRP attributes via communities. There are some odd design issues with this you can run into and just like this it leaves you with a sense of WTF!?! I think we had a similar thread about the same thing bit ago but it was for v4.

Route-maps are recommended to get the results you want.

[that1guy15]

So, what you're saying is... it's not the firewall.

it's always the firewall >;P

It's always the LOAD BALANCER.

Uh, if its not the network , nor the firewall or load balancer then what could it be??? I check my application service is running and I can ping the remote server so it cant be my app! Why does your network always suck!?!

[NetworkGroover]

Uh, if its not the network , nor the firewall or load balancer then what could it be??? I check my application service is running and I can ping the remote server so it cant be my app! Why does your network always suck!?!

Seems legit.

[NetworkGroover]

Yup, you beat me to the punch wintermute000.

Drill into your head that anytime EIGRP and BGP work together BGP will pass EIGRP attributes via communities. There are some odd design issues with this you can run into and just like this it leaves you with a sense of WTF!?! I think we had a similar thread about the same thing bit ago but it was for v4.

Route-maps are recommended to get the results you want.

Yet another reason not to run proprietary protocols.... 

[that1guy15]

Yup, you beat me to the punch wintermute000.

Drill into your head that anytime EIGRP and BGP work together BGP will pass EIGRP attributes via communities. There are some odd design issues with this you can run into and just like this it leaves you with a sense of WTF!?! I think we had a similar thread about the same thing bit ago but it was for v4.

Route-maps are recommended to get the results you want.

Yet another reason not to run proprietary protocols.... 

Cant go there. BGP does the same with OSPF in some situations. Why do you think vrf-lite exist?