Need some assistance determining exactly how the nexthop decision is made when a ABF forwarding rule is matched. My question is, does it do a lookup in the RIB or FIB and will the packet be handled via the actions specified by the results of that lookup?
I am trying to create an ABF rule which will match ipv6 traffic with a dscp marking of 7 and have it set the nexthop to a V6 labeled-unicast route which recurses to a 6PE next-hop which will then label the packet and send it to it's final destination. I am seeing in the logs is that the packet matches the ABF entry so the matching criteria appears correct. Unfortunately, the path is unchanged and the packet is not redirected to the nexthop I specify.
ABF entry::
ipv6 access-list ACL_IPV6_POLICY_ROUTING
130 permit ipv6 any any dscp 7 log nexthop1 ipv6 2001:506:100:f440::194:96
Log Entry showing packets matching::
RP/0/RSP0/CPU0:Aug 16 16:16:57.625 UTC: ipv6_acl_daemon[303]: %ACL-IPV6_ACL-6-IPACCESSLOGNP : access-list ACL_IPV6_POLICY_ROUTING (130) permit 58 2600:6ce2:0:2::1 -> 2001:506:100:f480::194:131, 4 packets
RP/0/RSP0/CPU0:Aug 16 16:16:57.625 UTC: ipv6_acl_daemon[303]: %ACL-IPV6_ACL-6-IPACCESSLOGP : access-list ACL_IPV6_POLICY_ROUTING (130) permit udp 2600:6ce2:0:2::1(32780) -> 2001:506:100:f480::194:131(33437), 1 packet
V6 Route for next-hop in RIB::
#show route ipv6 2001:506:100:f440::194:96
Routing entry for 2001:506:100:f440::194:96/128
Known via "bgp 65206", distance 200, metric 0, type internal
Installed Aug 15 21:41:09.752 for 19:27:10
Routing Descriptor Blocks
::ffff:96.34.226.91, from ::ffff:172.30.120.133
Nexthop in Vrf: "default", Table: "default", IPv4 Unicast, Table Id: 0xe0000000
Route metric is 0
No advertising protos.
V6 Route for 6PE route in RIB(Hitting the default)::
#show route ipv6 ::ffff:96.34.226.91
Routing entry for ::/0
Known via "isis default", distance 115, metric 100, candidate default path, type level-1
Installed May 30 22:29:15.191 for 11w0d
Routing Descriptor Blocks
fe80::d66d:50ff:fe93:c602, from 2001:506:100:f400::194:0, via Bundle-Ether3
Route metric is 100
No advertising protos.
V6 CEF entry for next-hop::
#show cef ipv6 2001:506:100:f440::194:96
2001:506:100:f440::194:96/128, version 26680183, internal 0x14004001 0x0 (ptr 0x779199dc) [1], 0x0 (0x0), 0x410 (0x7bf3fa00)
Updated Aug 15 21:41:09.750
Prefix Len 128, traffic index 0, precedence n/a, priority 4
BGP Attribute: id: 0x1f92, Local id: 0x2ad, Origin AS: 0, Next Hop AS: 0
via ::ffff:96.34.226.91, 3 dependencies, recursive [flags 0x6000]
path-idx 0 NHID 0x0 [0x71280244 0x0]
next hop VRF - 'default', table - 0xe0000000
next hop ::ffff:96.34.226.91 via ::ffff:96.34.226.91:0
next hop 96.34.12.13/32 BE2 labels imposed {16006 300112}
I would like to see the ABF action use the CEF entry to forward the packet and not the RIB entry, but I don't believe that's happening. Is that expected behavior?
I did try to set the nexthop on the ABF entry to the 6PE route and my commit failed
(config)#ipv6 access-list ACL_IPV6_POLICY_ROUTING
RP/0/RSP0/CPU0:crr01k1sbcc(config-ipv6-acl)# 130 permit ipv6 any any dscp 7 log nexthop1 ipv6 ::ffff:96.34.226.91
RP/0/RSP0/CPU0:crr01k1sbcc(config-ipv6-acl)#commit
% Failed to commit one or more configuration items during a pseudo-atomic operation. All changes made have been reverted. Please issue 'show configuration failed [inheritance]' from this session to view the errors
(config-ipv6-acl)#show configuration failed inheritance
!! SEMANTIC ERRORS: This configuration was rejected by
!! the system due to semantic errors. The individual
!! errors with each failed configuration command can be
!! found below.
ipv6 access-list ACL_IPV6_POLICY_ROUTING
130 permit ipv6 any any dscp 7 log nexthop1 ipv6 ::ffff:96.34.226.91
!!% V4 Mapped nexthop address: verify ACL config failed for ACL ACL_IPV6_POLICY_ROUTING seq 130
!
end
IOS-XR version is 5.1.3.
Any help would be greatly appreciated.
