05-25-2013 07:31 AM
Hi All,
I have a number of PEs peering with a RR, the aim is for these RR-clients to exchage their customers routes via the RR.
Now looking at the configuration below, i cannot see the need as to why "address-family ipv4" should be present in the config.
Can someone please tell me why if at all it should be in place?. (This is just one of the clients).
router bgp XX
bgp router-id 2.2.2.2
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 172.16.123.3 remote-as 9
neighbor 172.16.123.3 update-source Loopback0
!
address-family ipv4
neighbor 172.16.123.3 activate
neighbor 172.16.123.3 send-community
neighbor 172.16.123.3 route-reflector-client
exit-address-family
!
address-family vpnv4
neighbor 172.16.123.3 activate
neighbor 172.16.123.3 send-community
neighbor 172.16.123.3 route-reflector-client
exit-address-family
BR,
O.A
05-25-2013 08:42 AM
Hello,
If you want propagate only vpnv4 prefixes, IPv4 AF is not necessary in your config.
Best Regards
Please rate all helpful posts and close solved questions
05-25-2013 09:24 AM
Hi Blau,
Many thanks for your reply to my query. Unfortunately my question wasn't answered yet.
Dividing the configs into three, i know the first part establishes the TCP session, the third part enables MP-BGP between the PEs.
Now the second part is there "address-family ipv4", with or with it routes are reaching the right places, when do we really need it then?.
I will appreciate a more elaborate answer as why/when/how do we need it?.
Thanks,
O.A
05-25-2013 09:39 AM
Hello,
Sorry I did not realize that you wanted also explanation
BGP use address family model, so multiple AF were introduced. Basically it means what AF is used, that prefixes are exchanged:
IPv4 AF - used when IPv4 prefixes are exchanged
IPv6 AF - used when IPv6 prefixes are exchanged
VPNv4 AF - used when VPNv4 prefixes are exchanged
VPNv6 AF - used when VPNv6 prefixes are exchanged
For more details read thi post from Peter Paluch, which is extremly helpful:
https://supportforums.cisco.com/message/3615165#3615165
And also cisco documentation:
http://www.cisco.com/en/US/docs/ios/12_4t/ip_route/configuration/guide/tbrbover.html#wp1049730
Best Regards
Please rate all helpful posts and close solved questions
06-05-2013 11:29 PM
hi fellow
vpnv4 AF, as mentionned earlier will propagate vpnv4 routes on an MPLS backbone, by adding 1 bottom stack mpls label to identify destination vpn when packet is reaching outbound PE.
ipv4 AF does not use any labels. just a classical BGP peerings exchanging routes.
vpnv4 usually used on mpls bgp free core by ISP to isolate traffics between customers.
with ipv4 AF, all routers on the path have to be full mesh ( or connected to RR), and must be aware of all the routes.
so you could use one or another or both, depending on your setup.
usually on a BGP free core, vpnv4 is all that you need. now your customer might not need ipv4 AF. you have to understand exactly the network design for that, or give us a bit more info about your topology.
HTH
06-09-2013 03:59 AM
Hi,
you will need the AF IPV4 if your PE routers are exchanging routes in the Global routing table, for example some ISPs are ruunning their internet customers in the Global routing table ( which means that the customer interface in the Global not under VRF )
the VPNV4 AF will exchange the VRF routes not the Global one
Regards.
10-31-2018 03:02 PM
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