[c-nsp] Load balancing on portchan (4500X->ASR1006)

[CiscoNSP List]

Hi Everyone - Have a 4 port etherchan between ASR1006/4500X(In VSS) - Tried virtually all the load-balancing options on the 4500X, but port "1" in the portchan group always gets majority of traffic share.


Links are:


ASR1006      4500X (2)

0/0/3            1/1/4

1/0/0            1/1/16

1/0/3            2/1/4

2/0/0            2/1/16


src/dst ip - I get both ports on "primary" 4500X being primarily used (1/1/4 getting the most)

src/dst mac - I get a bit of a better load spread, but 2/1/4 gets very little traffic, and again 1/1/4 gets the most

src/dst port - 1/1/4 gets the most, 2/1/16 gets a lot more (ingress), 2/1/4, very little


The portchan peak usage is 2 to 2.5Gb/sec, but would do more, as it is being limited by the load-balancing....i.e 1/1/4 will max out at 1G/sec    (We have a very bursty traffic.....SP - So mix of Inet/L3VPN/backup/replication etc)


If anyone has some suggestions on how to achieve a better(more even) traffic spread, it would be greatly appreciated....Migrating to 10Gb is what we plan to do, but am interested in anyones comments on why 1/1/4 is used so heavily regardless of the load-balancing algorithm used (Assuming it is because it is the "first" port....spanning tree  probably preferring this port?)....the ASR1006 only has 2 load-balancing options flow-based or vlan-manual......lol and I dont have any interest in setting up manual vlan load-balancing 😉)


Thanks