MPLS VPNV4 with and Without BGP IPv4 Default Unicast Routing

MPLS VPNV4 with and Without BGP IPv4 Default Unicast Routing

Sharing is caring!

I have labbed up an MPLS network to do some captures of what the configurations look like both with and without Unicast BGP default enabled.  Including packet captures.  RR is a router reflector.  R2 is configured to have Default BGP IPv4 Unicast Routing turned on.  R3 is configured to have Default BGP IPv4 unicast routing turned off.  There is some slight differences in the configuration.   Obviously, we need the command “no bgp default ipv4-unicast” routing under the Router BGP 1000 process.  Additionally, the next-hop-self command MUST be moved under the vpn-v4 address family.

 

R2 – Configured WITH BGP IPv4 Default Unicast Routing

router bgp 1000
bgp log-neighbor-changes
neighbor 9.9.9.9 remote-as 1000
neighbor 9.9.9.9 update-source Loopback0
neighbor 9.9.9.9 next-hop-self
!
address-family vpnv4
neighbor 9.9.9.9 activate
neighbor 9.9.9.9 send-community extended
exit-address-family
!
address-family ipv4 vrf CUST-A
redistribute eigrp 1234
exit-address-family

 

R3 – Configured WITHOUT BGP IPv4 Default Unicast Routing

router bgp 1000
bgp log-neighbor-changes
no bgp default ipv4-unicast                          *****CHANGED*****
neighbor 9.9.9.9 remote-as 1000
neighbor 9.9.9.9 update-source Loopback0

(THE NEXT HOP SELF WAS MOVED UNDER AF VPNV4)          *****CHANGED*****

!
address-family ipv4
exit-address-family
!
address-family vpnv4
neighbor 9.9.9.9 activate
neighbor 9.9.9.9 send-community extended
neighbor 9.9.9.9 next-hop-self                                                          *****CHANGED*****
exit-address-family
!
address-family ipv4 vrf CUST-A
redistribute eigrp 1234
exit-address-family

 

Route Reflector Router

router bgp 1000
bgp log-neighbor-changes
neighbor IBGP peer-group
neighbor IBGP remote-as 1000
neighbor IBGP update-source Loopback0
neighbor 1.1.1.1 peer-group IBGP
neighbor 2.2.2.2 peer-group IBGP
neighbor 3.3.3.3 peer-group IBGP
neighbor 4.4.4.4 peer-group IBGP
!
address-family vpnv4
neighbor IBGP send-community extended
neighbor IBGP route-reflector-client
neighbor 1.1.1.1 activate
neighbor 2.2.2.2 activate
neighbor 3.3.3.3 activate
neighbor 4.4.4.4 activate
exit-address-family

 

R3#show ip bgp sum
R3#

***NOTE no output for ipv4 address family with this output***

R2#show ip bgp sum
BGP router identifier 2.2.2.2, local AS number 1000
BGP table version is 1, main routing table version 1

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
9.9.9.9 4 1000 42 31 1 0 0 00:22:36 0
R2#

***NOTE R2 does have an output for ipv4 address family with this output***

 

RR – Route Reflector

RR#show ip bgp sum
BGP router identifier 9.9.9.9, local AS number 1000
BGP table version is 1, main routing table version 1

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
1.1.1.1 4 1000 0 0 1 0 0 00:43:39 Idle
2.2.2.2 4 1000 33 44 1 0 0 00:24:21 0
3.3.3.3 4 1000 0 0 1 0 0 00:34:16 Idle
4.4.4.4 4 1000 0 0 1 0 0 00:56:45 Idle
RR#

****NOTE 1.1.1.1, 3.3.3.3, and 4.4.4.4 have been configured with the “no bgp default ipv4-unicast command

RR#show bgp vpnv4 unicast all sum
BGP router identifier 9.9.9.9, local AS number 1000
BGP table version is 167, main routing table version 167
12 network entries using 1872 bytes of memory
12 path entries using 960 bytes of memory
8/8 BGP path/bestpath attribute entries using 1280 bytes of memory
8 BGP extended community entries using 2000 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 6112 total bytes of memory
BGP activity 68/56 prefixes, 77/65 paths, scan interval 60 secs

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
1.1.1.1 4 1000 46 73 167 0 0 00:38:53 3
2.2.2.2 4 1000 33 45 167 0 0 00:24:49 3
3.3.3.3 4 1000 31 39 167 0 0 00:24:01 3
4.4.4.4 4 1000 66 101 167 0 0 00:56:55 3
RR#

The difference in the packet captures seems to be just the Optional Parameters.  R3 which is set for “no bgp default ipv4-unicast” will only have AFI 1 (IPv4) SAFI 128 (Labeled VPN Unicast).

And R2 has both that and the SAFI 128 Labeled VPN Unicast and SAFE 1 Unicast

R2 has both SAFI 128 Labeled VPN Unicast and SAFI 1 Unicast

Leave a Reply

Your email address will not be published.