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ASR1001X Etherchannel to 4500X - OSPF adjacency will not form when using VLAN based LB on ASR

josh.bresaw
Level 1
Level 1

Physical topology.  ASR1001X-->LACP-->4500X VSS

Logical topology.  ASR port channel 15.1250, /30 routed link to VSS port channel 15 trunk with vlan 1250.

OSPF adjacency between po15.1250 and vlan 1250 works fine when load balancing algorithm on ASR is set to default (flow based).

When load balancing algorithm is set to VLAN based, OSPF gets stuck in EXSTART. (MTU is identical on both sides).

The two devices can no longer ping eachother on VLAN 1250 when LB is set to VLAN based on ASR.

4500x EC LB global setting set to default src-dst-ip

The reason I want to change the load balancing on the ASR is because it will not accept a service-policy on a port-channel sub-interface unless the LB method is set to 'load-balance vlan'.

Relevant config below,  you'll notice I'm also doing OTV bridge groups on Po15 but that works fine with either LB method, its the layer 3 forwarding on the sub int that breaks.

interface Vlan1250
ip address 10.217.0.65 255.255.255.252

interface Port-channel15
switchport
switchport trunk native vlan 1000
switchport trunk allowed vlan 18,212,1000,1250
switchport mode trunk
switchport nonegotiate


router ospf x
no passive-interface Vlan1250
network 10.217.0.65 0.0.0.0 area 0

/////////////////////////////////////////////////////////////////////////

interface Port-channel15
no ip address
no negotiation auto
service instance 18 ethernet
encapsulation dot1q 18
bridge-domain 18
!
service instance 212 ethernet
encapsulation dot1q 212
bridge-domain 212
!
service instance 1000 ethernet
encapsulation untagged
bridge-domain 1000
!
end

interface Port-channel15.1250
encapsulation dot1Q 1250
ip address 10.217.0.66 255.255.255.252

router ospf x
no passive-interface Port-channel15.1250
network 10.217.0.66 0.0.0.0 area 0

3 Replies 3

Philip D'Ath
VIP Alumni
VIP Alumni

What software version are you running on your 1k?

Greetings Philip,

System image file is "bootflash:asr1001x-universalk9.03.16.03.S.155-3.S3-ext.SPA.bin"

That train is now up to 3.16.5S.

https://software.cisco.com/download/release.html?mdfid=284932298&softwareid=282046477&release=3.13.7S&relind=AVAILABLE&rellifecycle=ED&reltype=latest

Do you think you could move to the new version in that train?  It is likely to have a lot of bugs resolved - and possibly yours.

Review Cisco Networking for a $25 gift card