[alcatel-nsp] LAG on 7450 towards Juniper router

Rene Skjoldmose rene.skjoldmose at gmail.com
Sat Sep 19 11:06:11 EDT 2009


I have a customer that has 2x1Gbit connections in a LAG bundle.
I provide a VPRN service to the customer using an epipe from the 7450 
LAG port to a spoke-sdp on the VPRN interface on a 7750.

The problem is that when i look at the MRTG graph of the 7450 LAG port 
it stops at ~980mbit/s, and thus leaves me to believe that proper load 
balancing is not taking place.
The 980 mbit/s are outgoing traffic from my network towards a Juniper 
router at the customer premises.
The customer configures his own equipment.
Both ports on the 7450 are up, and member of the LAG pool.
The strange thing is that when i use the "monitor port x/x/x y/y/y rate 
interval 3" i get values that indicate near perfect balancing of the 
traffic in both directions, which does not make sense when looking at 
the ~980mbit/s max throughput.

How does the LAG load balancing algorithm work in the 7450?
 From what i can see, it is no longer possible to get snmp values from 
the physical ports once they are in a LAG pool - is that correct?

TimOS versions:
7450: 6.1r4
7750: 5.0r12


René Skjoldmose

More information about the alcatel-nsp mailing list