3Com Link Aggregation

[Gronkman]

Hi, we have taken over support of a LAN existing of 3Com 4400s, 4900s, 4050s and 5500s. There may be a configuration problem existing with a 4900 where ports 13, 14, 15 & 16 are configured as one Aggregated Link (with LACP being operational), yet ports 13 & 14 are connected to one 4050 (using Cat5), and ports 15 & 16 are connected to a 2nd 4050 (using Cat5), and both 4050s are part of an XRN fabric.

I believe this will not function as I think an Aggregated Link must only be connected between Switch #1 (4900) and Switch #2 (one of the 4050s), and not split between 1 switch (4900) and 2 switches (the 2 5500s within an XRN fabric) ..

Should I configure the 4900 ports 13 & 14 as one Aggregated Link and connect to the 1st 4050, and configure the 4900 ports 15 & 16 as a separate Aggregated Link and connect to the 2nd 4050 (although both 4050s are “one entity” as they are part of an XRN fabric)?

Am I correct in my assumption ?

Thanx .

 

[blueshark101]

No, one of the benefits of XRN is to allow you to remove a single point of failure from the infrastructure, so rather than having an aggregation link back to one device you spread the links across two.

Interestingly, 3Com engineers do NOT recommend using LACP, preferring to manually create the aggregation links. Although we have a number of customers using LACP without a problem.


-Blue
The significant problems we face cannot be solved at the same level of thinking we were at when we created them

 

[Gronkman]

Thanx blueshark101 for the response, I meant to respond earlier,I just got busy ...