[c-nsp] 3750 Etherchannel loadbalnace

[Chintan Shah]

Hi,

I have 3750 aggregation switches as aggregation layer to connect 2  access
router to Core router. 3750 runs e etherchannel from  to Core with 2 1 gig
link

I have src-mac based loadbalanced method used in 3750 and what I see
that 3750 use only one link part of ethrchannel so during test when i have
total traffic comming more than 1gig , i see drops....

Here are details :


Mac address : 000d.edac.8900 – Access Router 1

0006.d61b3c1a - Access Router r2

0015.c75d.d42c- Core router

sw1.LAB-3750G#show etherchannel summary | beg Group
Group  Port-channel  Protocol    Ports
------+-------------+-----------+-----------------------------------------------
1      Po1(SU)          -        Gi2/0/1(P)  Gi2/0/4(P)

sw1.LAB-3750G#


sw1.LAB-3750G#test etherchannel load-balance interface port-channel 1 mac
000d.edac.8900  0015.c75d.d42c

Would select Gi2/0/1 of Po1


sw1.LAB-3750G# test etherchannel load-balance interface port-channel 1 mac
0006.d61b.3c1a  0015.c75d.d42c

Would select Gi2/0/1 of Po1

As per above test, I see that 3750 select Gi2/0/1 for two source mac-address
and that's reason i have only one link utilized..

Does some body knows the algorithm used by  3750 for above two source-mac
address and how did it select always gi2/0/1 not other link for 2nd stream
of traffic ??

Unforutnately I can't do src-dst-ip based loadbalnace becuase incomming
traffic is MPLS labelled and existing 3750 doens't have capbility to
understand MPLS so it takes as non-ip traffic..


Thanks in advance,
Chintan