[c-nsp] IPv6 redistribute bgp into ospf

[Mike Leber]

Hi Tobias,

Not that the load of redistribution with IPv6 would be much due to the 
table size of IPv6, however I'd generally recommend a design that avoids 
the need to redistribute BGP tables into other routing protocols (also 
especially avoid redistributing any other routing protocols into BGP).

Alternative #1: Typically router0 in your scenario would be a non BGP 
speaking customer aggregation router that either can't run BGP or that 
you don't want to run BGP.  I'd suggest having router1 inject a default 
(default-originate) into ospf and then have router0 use that instead for 
reaching the Internet at large as well as any routes carried in BGP and 
not ospf.  This would eliminate the need to redistribute BGP into ospf.

Alternative #2: If the /48 route is not meant to be announced to the 
Internet at large (and either on an interface or statically routed) then 
I'd suggest carrying it in ospf on all three routers and not in BGP.

Alternative #3: I'd suggest running BGP on all three routers (probably 
not applicable to your situation).

Mike.

Tobias König wrote:
> Hi there
> 
> I ran into a problem when trying to redistribute a bgp ipv6 route into ospf.
> 
> The scenario looks the following:
> 
> router0 <-- ospf (10:10:10::4/126) --> router1 <-- bgp (10:10:10::/126) -->
> router2
> 
> Router2 advertises an ipv6 prefix (20:20:20::/48) via ibgp to router1, this
> part works flawlessly.
> Router1 should then redistribute that route into its ospf process and
> advertise it to router0, which unfortunately it doesn't.
> (When redistributing a static route on router1 into ospf, router0 sees that
> prefix).
> 
> Maybe someone of you got any idea of what could be wrong or can provide a
> hint on where to find detailed infos.
> 
> You can find the according configs at the bottom. The config was tested with
> the following platforms and IOS -> always the same result:
> c2800nm-advipservicesk9-mz.124-19
> c3640-js-mz.124-23.bin
> c3640-ik9s-mz.124-19.bin
> 
> Thanks in advance for any inputs.
> 
> Cheers
> 
> Tobias
> 
> 
> ---- sh ipv6 route
> R0#sh ipv6 route
> C   10:10:10::4/126 [0/0]
>      via ::, FastEthernet0/0
> 
> R1#sh ipv6 route
> C   10:10:10::/126 [0/0]
>      via ::, FastEthernet1/0
> C   10:10:10::4/126 [0/0]
>      via ::, FastEthernet0/0
> B   20:20:20::/48 [200/0]
>      via 10:10:10::2
> 
> R2#sh ipv6 route
> B   ::/0 [200/0]
>      via 10:10:10::1
> C   10:10:10::/126 [0/0]
>      via ::, FastEthernet0/0
> S   20:20:20::/48 [1/0]
>      via ::, Null0
> 
> Config:
> =====
> router0:
> ----
> interface FastEthernet0/0
>  ipv6 address 10:10:10::5/126
>  ipv6 enable
>  ipv6 ospf 1 area 0
> 
> ipv6 router ospf 1
>  router-id 10.10.10.0
>  log-adjacency-changes
>  passive-interface default
>  no passive-interface FastEthernet0/0
> ----
> 
> router1:
> ----
> interface FastEthernet0/0
>  ipv6 address 10:10:10::6/126
>  ipv6 enable
>  ipv6 ospf 1 area 0
> !
> interface FastEthernet1/0
> ipv6 address 10:10:10::1/126
>  ipv6 enable
> !
> router bgp 10
>  bgp router-id 10.10.10.1
>  bgp log-neighbor-changes
>  neighbor 10:10:10::2 remote-as 10
>  neighbor 10:10:10::2 version 4
>  !
>  address-family ipv4
>   no neighbor 10:10:10::2 activate
>   no auto-summary
>   no synchronization
>  exit-address-family
>  !
>  address-family ipv6
>   neighbor 10:10:10::2 activate
>   neighbor 10:10:10::2 send-community
>   neighbor 10:10:10::2 default-originate
>   neighbor 10:10:10::2 soft-reconfiguration inbound
>   no synchronization
>  exit-address-family
> 
> ipv6 router ospf 1
>  router-id 10.10.10.1
>  log-adjacency-changes
>  passive-interface default
>  no passive-interface FastEthernet0/0
>  redistribute bgp 10
> ----
> 
> router2:
> ----
> interface FastEthernet0/0
>  ipv6 address 10:10:10::2/126
>  ipv6 enable
> !
> router bgp 10
>  bgp router-id 10.10.10.2
>  bgp log-neighbor-changes
>  neighbor 10:10:10::1 remote-as 10
>  neighbor 10:10:10::1 version 4
>  !
>  address-family ipv4
>   no neighbor 10:10:10::1 activate
>   no auto-summary
>   no synchronization
>  exit-address-family
>  !
>  address-family ipv6
>   neighbor 10:10:10::1 activate
>   neighbor 10:10:10::1 send-community
>   neighbor 10:10:10::1 soft-reconfiguration inbound
>   network 20:20:20::/48
>  exit-address-family
> !
> ipv6 route 20:20:20::/48 Null0
> ----
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