08-29-2015 03:14 PM - edited 03-05-2019 02:11 AM
An issue came While practicing for Route-reflector with R1, R2, R3, R4 in AS 111, R5 in AS 555 and R6 in AS. All the routes are being advertised to all the neighbor but the routes learned from RR is not installed as the best one. I issued Next hop self command on R1 for all the BGP pairs. But still R1 is not changing the next hop IP while advertising the attributes. Wanted to know if next-hop not supported while doing RR. Below is the output from R3 and config of R1. Please help me out. R3#sh ip bgp BGP table version is 2, local router ID is 3.3.3.3 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path * i2.3.4.0/24 22.22.11.1 0 100 0 i *> 3.4.5.0/24 0.0.0.0 0 32768 i * i4.5.6.0/24 11.11.44.2 0 100 0 i * i5.6.7.0/24 22.22.11.1 0 100 0 555 i * i55.56.57.0/24 22.22.11.1 0 100 0 555 i * i66.66.1.0/24 11.11.44.2 0 100 0 666 i * i66.66.2.0/24 11.11.44.2 0 100 0 666 i R3# R1#sh run | sec bgp router bgp 111 bgp router-id 1.1.1.1 bgp log-neighbor-changes neighbor 11.11.33.2 remote-as 111 neighbor 11.11.44.2 remote-as 111 neighbor 22.22.11.1 remote-as 111 ! address-family ipv4 neighbor 11.11.33.2 activate neighbor 11.11.33.2 route-reflector-client neighbor 11.11.33.2 next-hop-self neighbor 11.11.33.2 soft-reconfiguration inbound neighbor 11.11.44.2 activate neighbor 11.11.44.2 route-reflector-client neighbor 11.11.44.2 next-hop-self neighbor 11.11.44.2 soft-reconfiguration inbound neighbor 22.22.11.1 activate neighbor 22.22.11.1 next-hop-self neighbor 22.22.11.1 soft-reconfiguration inbound
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08-30-2015 12:15 AM
Hi,
from Cisco BGP documentation:
Do not use the neighbor next-hop-self command to modify the next hop attribute for a route reflector when this feature is enabled for a route reflector client. Using the neighbor next-hop-self command on the route reflector will modify next hop attributes only for routes that are learned from eBGP peers and not the intended routes that are being reflected from the route reflector clients. To modify the next hop attribute when reflecting a route, use an outbound route map.
However, in some recent IOS an "all" option is available for the "neighbor next-hop-self" command which seems to change the next hops of reflected routes as well:
If you do not use the optional all keyword, the next hop of only eBGP-learned routes will be updated by the RR. With the all keyword configured, the next hop of both eBGP- and iBGP-learned routes will be updated by the RR.
HTH
Rolf
08-30-2015 12:15 AM
Hi,
from Cisco BGP documentation:
Do not use the neighbor next-hop-self command to modify the next hop attribute for a route reflector when this feature is enabled for a route reflector client. Using the neighbor next-hop-self command on the route reflector will modify next hop attributes only for routes that are learned from eBGP peers and not the intended routes that are being reflected from the route reflector clients. To modify the next hop attribute when reflecting a route, use an outbound route map.
However, in some recent IOS an "all" option is available for the "neighbor next-hop-self" command which seems to change the next hops of reflected routes as well:
If you do not use the optional all keyword, the next hop of only eBGP-learned routes will be updated by the RR. With the all keyword configured, the next hop of both eBGP- and iBGP-learned routes will be updated by the RR.
HTH
Rolf
08-30-2015 12:33 AM
Thanks Rolf for easing my BGP life :)
11-17-2019 09:03 AM
To modify the next hop attribute when reflecting a route, use an outbound route map.
I've tried that but it didn't work:
R1(config)#do sh run | s router bgp
router bgp 123
bgp router-id 1.1.1.1
bgp log-neighbor-changes
redistribute connected
neighbor 2.2.2.2 remote-as 123
neighbor 2.2.2.2 update-source Loopback0
neighbor 2.2.2.2 route-reflector-client
neighbor 2.2.2.2 route-map NEXT_HOP_SELF out
neighbor 3.3.3.3 remote-as 123
neighbor 3.3.3.3 update-source Loopback0
neighbor 3.3.3.3 route-reflector-client
neighbor 3.3.3.3 route-map NEXT_HOP_SELF out
R1(config)#route-map NEXT_HOP_SELF permit 10
R1(config-route-map)#set ip next-hop self
% "NEXT_HOP_SELF" used as BGP outbound route-map, set use own IP/IPv6 address for the nexthop not supported
% "NEXT_HOP_SELF" used as BGP outbound route-map, set use own IP/IPv6 address for the nexthop not supported
I removed the route-map and configured "neighbor x.x.x.x next-hop-self all" and it worked like a charm :)
Thanks!
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