02-01-2016 05:11 AM - edited 03-05-2019 03:14 AM
Hello,
I am peering with various IPV6 peers and i am receiving routes from my peers but I am not installing routes in my routing table.
Below are various outputs (output values are truncated)
1. shows the ipv6 bgp output table, showing a neighbor and amounf of the prefixes received.
2. shows the ipv6 routes received from the neighbor BBBB:BBB:1::a500:BBB:B, (other routes have been removed)
3. shows that the next hops are reachable
I am using an ASR 9001 - S, IOS XR version 5.1.2
RP/0/RSP0/CPU0:#sh bgp ipv6 unicast summary
Mon Feb 1 13:50:59.399 WAT
BGP router identifier XX.XX.XX.XX, local AS number XXXXX
BGP generic scan interval 60 secs
BGP table state: Active
Table ID: 0xe0800000 RD version: 3007
BGP main routing table version 3007
BGP scan interval 60 secs
BGP is operating in STANDALONE mode.
Process RcvTblVer bRIB/RIB LabelVer ImportVer SendTblVer StandbyVer
Speaker 3007 1 0 3007 1 0
Neighbor Spk AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down St/PfxRcd
BBBB:BBB:1::a500:BBB:B
0 XXX 3917 3858 0 0 0 1d07h 5
.................................................................
RP/0/RSP0/CPU0:#sh bgp ipv6 unicast neighbors BBBB:BBB:1::a500:BBB:B routes
Mon Feb 1 13:53:23.092 WAT
BGP router identifier XX.XX.XX.XXX, local AS number XXXX
BGP generic scan interval 60 secs
BGP table state: Active
Table ID: 0xe0800000 RD version: 3007
BGP main routing table version 3007
BGP scan interval 60 secs
Status codes: s suppressed, d damped, h history, * valid, > best
i - internal, r RIB-failure, S stale, N Nexthop-discard
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* CCCC:CCC:CCC::/48 BBBB:BBB:1::a500:BBB:B
0 0 XXX i
................................................................
RP/0/RSP0/CPU0:#ping BBBB:BBB:1::a500:BBB:B
Mon Feb 1 13:54:12.683 WAT
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to BBBB:BBB:1::a500:BBB:B, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 123/124/125 ms
02-02-2016 03:17 AM
What is the output of:
show bgp ipv6 unicast CCCC:CCC:CCC::/48
Could you maybe post the output of:
debug bgp vpnv6 unicast
and then reset the BGP IPv6 peer.
02-02-2016 11:26 AM
Hello Philip,
the second suggestion is out of context the original poster is not running 6VPE, it is simply a question of multiple eBGP peerings in IPv6. The path from this neighbor is not the best so it is not installed in the IPv6 routing table.
Hope to help
Giuseppe
02-02-2016 11:38 AM
I just posted the prefix above as an example.
None of the ipv6 prefixes i am receiving are installed in the routing table, even best
RP/0/RSP0/CPU0:#sh bgp ipv6 unicast
Tue Feb 2 20:32:43.057 WAT
BGP router identifier 44.44.44.444, local AS number 333XX
BGP generic scan interval 60 secs
BGP table state: Active
Table ID: 0xe0800000 RD version: 3531
BGP main routing table version 3531
BGP scan interval 60 secs
Status codes: s suppressed, d damped, h history, * valid, > best
i - internal, r RIB-failure, S stale, N Nexthop-discard
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* 2001::/32 2001:FFF:F::a500:FFFF:1
100 0 2222 1111 0000 i
* 2001:FFF:F::a500:FFFF:1
30 0 6666 29900 i
* 2001:FFF:F::FFFF:1
40 0 6666 23232 i
*> 2001:FFF:F::FFFF:1
0 0 9999 i
output truncated
ALl i get in my table are directly connected routes
RP/0/RSP0/CPU0:INT-IXP-A9K-PR-01#sh route ipv6
Tue Feb 2 20:35:19.856 WAT
Codes: C - connected, S - static, R - RIP, B - BGP, (>) - Diversion path
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - ISIS, L1 - IS-IS le
vel-1, L2 - IS-IS level-2
ia - IS-IS inter area, su - IS-IS summary null, * - candidate default
U - per-user static route, o - ODR, L - local, G - DAGR
A - access/subscriber, a - Application route, (!) - FRR Backup path
Gateway of last resort is not set
C 2001:FFF:X::/64 is directly connected,
2d18h, GigabitEthernet0/0/1/0
L 2001:FFF:X::a503:FFFF:1/128 is directly connected,
2d18h, GigabitEthernet0/0/1/0
C 2001:FFF:X::/64 is directly connected,
2d14h, TenGigE0/0/2/1
L 2001:FFF:X::FFFF:1/128 is directly connected,
2d14h, TenGigE0/0/2/1
02-02-2016 11:30 AM
Output
RP/0/RSP0/CPU0:#sh bgp ipv6 unicast CCCC:C:CCC::/48
Tue Feb 2 20:08:12.390 WAT
BGP routing table entry for CCCC:C:CCC::/48
Versions:
Process bRIB/RIB SendTblVer
Speaker 2304 2304
Last Modified: Jan 31 06:28:09.353 for 2d13h
Paths: (1 available, best #1)
Not advertised to any peer
Path #1: Received by speaker 0
Not advertised to any peer
ASAS
XXXX:XXX:X::XXX:1 from XXXX:XXX:X::XXX:1 (22.22.222.2)
Origin IGP, metric 0, localpref 100, valid, external, best, group-best, import-candidate
Received Path ID 0, Local Path ID 1, version 2304
Community: 55555:ASAS
Origin-AS validity: not-found
Re;
debug bgp vpnv6 unicast
I am guessing the syntax for the command in ios xr is different, so i ran the debug command below
"debug bgp address-family vpnv6 unicast" this however did not produce any output and i think that is fine cause i am not receiving any vpnv6 routes, so i ran the debug for ipv6 unicast i.e.
debug bgp address-family ipv6 unicast,
Below is the output
RP/0/RSP0/CPU0:Feb 2 20:14:36.458 WAT: bgp[1054]: %ROUTING-BGP-5-ADJCHANGE_DETAIL : neighbor XXXX:XXX:X::XXX:1 Up (VRF: default; AFI/SAFI: 2/1) (AS: ASAS)
RP/0/RSP0/CPU0:Feb 2 20:14:37.608 WAT: bgp[1054]: [default-rtr] (ip6u): ===bgp_add_path===: net=3333:0:333::/48, nver=3527, nfl=0x04000001: newpath=0x51097a10(XXXX:XXX:X::XXX:1/128,XXXX:XXX:X::XXX:1,0,0x4000000000020001): link=1, pcount=1
RP/0/RSP0/CPU0:Feb 2 20:14:37.608 WAT: bgp[1054]: [default-rtr] (ip6u): Not an import multipath -> import multipath for 3333:0:333::/48 from XXXX:XXX:X::XXX:1 (path: ASAS)
RP/0/RSP0/CPU0:Feb 2 20:14:37.608 WAT: bgp[1054]: [default-rtr] (ip6u): ===bgp_bestpath===: net=2620:0:870::/48, nver=3527, nfl=0x04000001: lastpath=0x51097a10(XXXX:XXX:X::XXX:1/128,XXXX:XXX:X::XXX:1,0,0x4000000000020001): PELEM=0x0(lpathid=0, ver=0, fl=0x00000000, path=0x0)
RP/0/RSP0/CPU0:Feb 2 20:14:37.608 WAT: bgp[1054]: [default-rtr] (ip6u): ===bgp_calculate_bestpath===: net=3333:0:333::/48, nver=3527, nfl=0x04040001, pelemver=3527: oldbest=0x0(NULL,::,0), newbest=0x51097a10(XXXX:XXX:X::XXX:1/128,2001:XXXX:XXX:X::XXX:10), bumpv=1
RP/0/RSP0/CPU0:Feb 2 20:14:37.608 WAT: bgp[1054]: [default-rtr] (ip6u): ===bgp_change_bestpath===: net=3333:0:333::/48, nver=3527, nfl=0x04040001: oldbest=0x0: PELEM=0x510b8e04(lpathid=1, ver=3527, fl=0x00001101, path=0x51097a10)
RP/0/RSP0/CPU0:Feb 2 20:14:37.608 WAT: bgp[1054]: [default-rtr] (ip6u): ===bnet_chgflags_update===: net=3333:0:333::/48, nver=3527, nfl=0x04040001: oldtblattr=0x0, oldnh=0x0: PELEM=0x510b8e04(lpathid=1, ver=3527, fl=0x00001101, path=0x51097a10)
RP/0/RSP0/CPU0:Feb 2 20:14:37.608 WAT: bgp[1054]: [default-rtr] (ip6u): ===bgp_bestpath===: COMPLETE: net=3333:0:333::/48, nver=3527, nfl=0x04044001: pselect=0, bumpv=1(1:1,0,0,0)
02-02-2016 11:35 AM
Could you post the output of:
show ipv6 route CCCC:C:CCC::/48
02-02-2016 11:41 AM
RP/0/RSP0/CPU0:#sh route ipv6 CCCC:C:CCC::/48
Tue Feb 2 20:40:16.039 WAT
% Network not in table
02-23-2016 03:17 AM
Hello,
Had to contact Cisco TAC, turned out to be a software bug.
"CSCuq79148 - BGP label thread is stuck in CDM init:"
This bug is fixed starting with IOS XR 5.1.3 so an IOS upgrade is required.
The workaround is to reset the BGP process which i did and i can install IPV6 routes now.
Thank you all
02-23-2016 05:25 AM
Hello M-oyegunle,
you have been kind to provide feedback on this issue. Now this thread has an happy end.
So it was a SW bug.
Best Regards
Giuseppe
02-02-2016 11:44 AM
Hello, m-o
there is a single BGP advertisement for the prefix and it is considered best. it should be installed.
is the prefix learned in some other way a static route?
RP/0/RSP0/CPU0:#sh bgp ipv6 unicast CCCC:C:CCC::/48
Tue Feb 2 20:08:12.390 WAT
BGP routing table entry for CCCC:C:CCC::/48
Versions:
Process bRIB/RIB SendTblVer
Speaker 2304 2304
Last Modified: Jan 31 06:28:09.353 for 2d13h
Paths: (1 available, best #1)
Not advertised to any peer
Path #1: Received by speaker 0
Not advertised to any peer
ASAS
XXXX:XXX:X::XXX:1 from XXXX:XXX:X::XXX:1 (22.22.222.2)
Origin IGP, metric 0, localpref 100, valid, external, <<<<best<<<, group-best, import-candidate
Received Path ID 0, Local Path ID 1, version 2304
Community: 55555:ASAS
Origin-AS validity: not-found
Do you know that you need a policy written in RPL to accept the prefix from an eBGP peer in IOS XR?
Have you applied a policy like
route-policy PASS-ALL
pass
end-policy
see
http://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k_r5-3/routing/configuration/guide/b_routing_cg53xasr9k/b_routing_cg53xasr9k_chapter_010.html#con_1197962
Hope to help
Giuseppe
02-02-2016 12:12 PM
No the prefix is not learned via any other way.
and yes i have route policies applied in both inbound and outbound directions
02-02-2016 03:18 AM
You definately have ipv6 unicast routing enabled?
ipv6 unicast-routing
02-02-2016 11:06 AM
ipv6 unicast-routing is enabled by default in IOS_XR yeah?
02-02-2016 11:24 AM
Hello, m-oyegunle yes ipv6 unicast routing is enabled by default in IOS XR.
I don't see the '>' near the CCCC:CCCC:CCC::/48 prefix, you may be learning the prefix in some other way?
the missing '>' means the BGP is not considered best by BGP.
Your router might have installed the prefix from another eBGP session.
Hope to help
Giuseppe
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