2600 causes mail with attachments to crawl at modem speeds???

[GeneralDzur]

Just recently re-loaded & re-configured this router from scratch, and we're using the EXACT same config on another router at a different location, with no problems.

We're experiencing a very interesting problem: When using the Cisco, mail with attachments slows to a crawl...I mean bits per second. All other traffic goes at about 356Kb to 900Kb. The downstream is 2048Kb, and upstream is 512Kb.

It only happens with email, and only if they have an attachment. We can't figure this out. Both sites are using the same service provider.

When we switch over to using a small Linksys SOHO router, it does fine with no problems.

Any ideas? This is really buggering me

- stephan

 

[jneiberger]

When using the Cisco router, do you see errors on any of your interfaces? Does it happen with *all* email with attachments or only certain attachments?

 

[GeneralDzur]

With any attachment over roughly 400k.

I'll ask my guy at that site to pull up the Show Interfaces and send it to me.

- stephan

 

[jneiberger]

That's interesting. It doesn't usually happen with attachments smaller than 400 KB? I would immediately look for a duplex mismatch. Perhaps the Ethernet interfaces on the Cisco router and the Linksys behave differently.

How do you have the router configured for speed and duplex? What switch is the router connected to, and how do you have speed and duplex set on the switch interface?

 

[GeneralDzur]

Turns out it was a duplex mismatch. The satellite uplinks indoor unit (IDU) was only set for half-duplex, and the router was set at full-duplex.

- stephan

 

[jneiberger]

Get used to troubleshooting duplex mismatches. You'll see a lot of them.