3Com 4900 Switch Table Problem

[Guest]

Archived from groups: comp.dcom.lans.ethernet (More info?)

I am having a strange problem with a 3Com 4900 switch and three 4250
switches.

My configuration looks like this

[4900]
| | |
| | |--[4250]
| |
| |----[4250]
|
|------[4250]

The problem is that on a regular basis, random PC's attached to the
4250 switches are unable to ping one or more servers attached to the
4900 switch. Repatching the workstation to a different 4250 resolves
the problem. I was seeing this problem about a year ago and thought
it was resolved. All of the 4250 switches are new whereas the 4900
was involved in the previous problems. It seems that the 4900
incorrectly learns the workstation MAC...

Has anyone else run into anything like this or can suggest what might
be causing it?

Cheers.

Robin

 

[Guest]

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <e3cac15a.0411080802.3f9021fa@posting.google.com>,
rgwynne@municipalsoftware.com (Robin Gwynne) writes:
>I am having a strange problem with a 3Com 4900 switch and three 4250
>switches.
>
>My configuration looks like this
>
>[4900]
> | | |
> | | |--[4250]
> | |
> | |----[4250]
> |
> |------[4250]
>
>The problem is that on a regular basis, random PC's attached to the
>4250 switches are unable to ping one or more servers attached to the
>4900 switch. Repatching the workstation to a different 4250 resolves
>the problem. I was seeing this problem about a year ago and thought
>it was resolved. All of the 4250 switches are new whereas the 4900
>was involved in the previous problems. It seems that the 4900
>incorrectly learns the workstation MAC...
>
>Has anyone else run into anything like this or can suggest what might
>be causing it?

First of all, you should dump the forwarding information base (FID)
of the switches if the error occurs and check if necessary entries
are missing. Then you have to trace where the request (or reply)
actually gets lost.
This should not occur even if flooding to unknown destinations is
inhibited, as long as the FID timeout is greater than the ARP timeout
of a (potentially quiet) server.

A similar issue involving 3Com SS II 3300 and NT4-stations came
up in this group several years ago and AFAIR even 3Com could not
do anything about it.

--
Manfred Kwiatkowski kwiatkowski@zrz.tu-berlin.de

 

[Guest]

Archived from groups: comp.dcom.lans.ethernet (More info?)

Dear Robin,

I am experience the same problem, i am have the same equipaments but this
equipaments are connected using XRN technologies.

My configuration looks like this:
This 2 4950 switch CORE connected using XRN, the connecteds for 4924 2
cables using link agregation, one cable connected in 4950 primary unit, in
second cable connected in 4950 secondary unit.

The same workstations connected in switch 4924 sometimes pings the servers
sometimes don`t.


-------------------------------------
Robin Gwynne wrote:


> I am having a strange problem with a 3Com 4900 switch and three 4250
> switches.

> My configuration looks like this

> [4900]
> | | |
> | | |--[4250]
> | |
> | |----[4250]
> |
> |------[4250]

> The problem is that on a regular basis, random PC's attached to the
> 4250 switches are unable to ping one or more servers attached to the
> 4900 switch. Repatching the workstation to a different 4250 resolves
> the problem. I was seeing this problem about a year ago and thought
> it was resolved. All of the 4250 switches are new whereas the 4900
> was involved in the previous problems. It seems that the 4900
> incorrectly learns the workstation MAC...

> Has anyone else run into anything like this or can suggest what might
> be causing it?

> Cheers.

> Robin






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[slack_guru]

hi, i'm trying to broadband a internet connection through my 3com 4500 switch but not reaching.

situation: internet adsl router, my computer nic card must have ip 200.161.131.72 and gateway 200.161.131.65 for internet connection.

can i plug the internet router directly to 3com switch to broadband connection ?

i've tried this, put 200.161.131.72 for switch ip address; 200.161.131.65 and my internal lan 200.161.131.0 in the switch static routing table and nothing happens

what would be the appropriate configuration for this situation ?

thanks