CEF problem - Traffic forwarding
Hello, I have a very strange problem on my ASR-1006 BRAS router. This router is having two equal paths toward a P router via IS-IS. The BRAS is seeing the P router over the two paths and the two paths are installed in the RIB and FIB as follows: bng.rams.ca.asr1#sh ip cef 10.10.10.141 internal 10.10.10.141/32, epoch 3, RIB[I], refcount 6, per-longest-match-prefix sharing sources: RIB, LTE feature space: IPRM: 0x00028000 Broker: linked, distributed at 1st priority LFD: 10.10.10.141/32 1 local label local label info: global/592 contains path extension list disposition chain 0x7FCE5CB8C440 label switch chain 0x7FCE5CB82FC0 ifnums: GigabitEthernet0/0/0(8): 172.17.11.9 GigabitEthernet1/0/0(24): 172.17.11.17 path 7FCE67248388, path list 7FCE5FF51A40, share 1/1, type attached nexthop, for IPv4 MPLS short path extensions: MOI flags = 0x0 label implicit-null nexthop 172.17.11.9 GigabitEthernet0/0/0, adjacency IP adj out of GigabitEthernet0/0/0, addr 172.17.11.9 7FCE5C406958 path 7FCE6724B5B8, path list 7FCE5FF51A40, share 1/1, type attached nexthop, for IPv4 MPLS short path extensions: MOI flags = 0x0 label implicit-null nexthop 172.17.11.17 GigabitEthernet1/0/0, adjacency IP adj out of GigabitEthernet1/0/0, addr 172.17.11.17 7FCE5079A540 output chain: IP adj out of GigabitEthernet0/0/0, addr 172.17.11.9 7FCE5C406958 The problem is, CEF is seeing the two paths equal, but the output chain is only having one exit interface and the traffic is traversing this interface only! This is the interface config: bng.rams.ca.asr1#sh run all | sec 0/0/0 interface GigabitEthernet0/0/0 description "Connected to p1 router" mtu 1600 ip address 172.17.11.10 255.255.255.252 ip redirects ip unreachables ip proxy-arp ip mtu 1600 no ip load-sharing per-longest-match-prefix ip cef accounting non-recursive internal ip router isis ip flow monitor adsl input ip flow monitor adsl output ip pim dr-priority 1 ip pim query-interval 30 ip mfib forwarding input ip mfib forwarding output ip mfib cef input ip mfib cef output ip route-cache cef ip route-cache ip split-horizon ip igmp last-member-query-interval 1000 ip igmp last-member-query-count 2 ip igmp query-max-response-time 10 ip igmp version 2 ip igmp query-interval 60 ip igmp tcn query count 2 ip igmp tcn query interval 10 interface GigabitEthernet1/0/0 description " Connected to p1 router" mtu 1600 ip address 172.17.11.18 255.255.255.252 ip redirects ip unreachables ip proxy-arp ip mtu 1600 no ip load-sharing per-longest-match-prefix ip cef accounting non-recursive internal ip router isis ip flow monitor adsl input ip flow monitor adsl output ip pim dr-priority 1 ip pim query-interval 30 ip mfib forwarding input ip mfib forwarding output ip mfib cef input ip mfib cef output ip route-cache cef ip route-cache ip split-horizon ip igmp last-member-query-interval 1000 ip igmp last-member-query-count 2 ip igmp query-max-response-time 10 ip igmp version 2 ip igmp query-interval 60 ip igmp tcn query count 2 ip igmp tcn query interval 10 So, what do you think? Regards, Mohamed Kamal
Hello Mohamed,
Your cef has load sharing disabled on the interface.
no ip load-sharing per-longest-match-prefix Yes, and when I try to configure ip load-sharing per-destination, I get
On 9/15/2014 2:50 PM, lek wrote: the following error message: %Cannot change the load sharing mode: Per-session QoS Regards, Mohamed Kamal Network Engineer, Core Team NOOR Data Networks, SAE City Stars Capital 5 A4 Omar Ibn El Khattab Street Heliopolis, Cairo, Egypt Mobile GSM.: +2 0100 29 49 691 Land Line.: +20 2 16700 Ext.: 139 Fax.: +20 2 3748 2816 Email.: mkamal@noor.net
participants (2)
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lek
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Mohamed Kamal