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From: smokinpope on 19 Jun 2008 12:05
I realize I am posting this in a Cisco Group, But I am hoping maybe
someone can provide me with some direction or some fresh insight as to
go about troubleshooting this issue. Nortel does not seem to have any
helpful documentation and their tech support team blows.

The company I work for recently purchased two Nortel secure 4134
routers. One for our corporate office and one for our D.R. site. They
are replacing our Nortel BLN Routers. We have had nothing but a hard
time getting these routers implemented. After configuration, when
implemented we were not able to get any of our thin clients, printers
or RDP sessions from our remote locations to connect. Even while using
a 45Mbs DS3 Circuit, lower end services such as ping, telnet, snmp
worked without any issues. It appeared to affect only the higher level
functions. After researching we were told our MTU setting my was set
too low at 1500. We then bumped up the MTU to 1601 and disabled
fragmentation_RFC_1490.

Upon our next test, when we implemented, everything appeared to
working fine, print jobs were working, thin clients were able to
connect, we could even VNC to pc's at the remote locations. Seemed
pretty fast as well. Now granted we were testing on a Sunday, not many
of our remote locations were even open. But it seemed like the MTU and
Fragmentation changes resolved the issue. On Monday however at 7:00am
our entire network came to a crawl. Everything was still working, just
extremely slow, 10-15 mins to log onto a thin client. print jobs would
hang...etc. When we looked at our Network Utilization we were only
using 20Mbs of out 45Mbs pipe. Due to the fact that I was not here
during the slowdown. I was not able to get any pcaps on the either the
T3 interface or Ethernet interface. I was even told to see if Auto
QOS was
causing an issue. However as soon as we switched back to our trusted
BLN. The network came back instantaneously, and started running fine
again.

My question is this. Is any one else using this particular model of
router? If,so has anyone experienced the same kind of issue? I have
tried looking on Nortel's website, but all the documentation they have
does not go very in depth, mostly just configuration and limited
troubleshooting. Unfortunately I am more familiar with Cisco routers,
than I am with Nortel. Any help would be greatly appreciated, I am
basically looking for more info, either from forums, other news
groups, etc... Thank you
From: J.Cottingim on 20 Jun 2008 10:56
On Jun 19, 11:05 am, smokinpope <keystro...(a)gmail.com> wrote:
> I realize I am posting this in a Cisco Group, But I am hoping maybe
> someone can provide me with some direction or some fresh insight as to
> go about troubleshooting this issue. Nortel does not seem to have any
> helpful documentation and their tech support team blows.
>
> The company I work for recently purchased two Nortel secure 4134
> routers. One for our corporate office and one for our D.R. site. They
> are replacing our Nortel BLN Routers. We have had nothing but a hard
> time getting these routers implemented. After configuration, when
> implemented we were not able to get any of our thin clients, printers
> or RDP sessions from our remote locations to connect. Even while using
> a 45Mbs DS3 Circuit, lower end services such as ping, telnet, snmp
> worked without any issues. It appeared to affect only the higher level
> functions. After researching we were told our MTU setting my was set
> too low at 1500. We then bumped up the MTU to 1601 and disabled
> fragmentation_RFC_1490.
>
> Upon our next test, when we implemented, everything appeared to
> working fine, print jobs were working, thin clients were able to
> connect, we could even VNC to pc's at the remote locations. Seemed
> pretty fast as well. Now granted we were testing on a Sunday, not many
> of our remote locations were even open. But it seemed like the MTU and
> Fragmentation changes resolved the issue. On Monday however at 7:00am
> our entire network came to a crawl. Everything was still working, just
> extremely slow, 10-15 mins to log onto a thin client. print jobs would
> hang...etc. When we looked at our Network Utilization we were only
> using 20Mbs of out 45Mbs pipe. Due to the fact that I was not here
> during the slowdown. I was not able to get any pcaps on the either the
> T3 interface or Ethernet interface. I was even told to see if Auto
> QOS was
> causing an issue. However as soon as we switched back to our trusted
> BLN. The network came back instantaneously, and started running fine
> again.
>
> My question is this. Is any one else using this particular model of
> router? If,so has anyone experienced the same kind of issue? I have
> tried looking on Nortel's website, but all the documentation they have
> does not go very in depth, mostly just configuration and limited
> troubleshooting. Unfortunately I am more familiar with Cisco routers,
> than I am with Nortel. Any help would be greatly appreciated, I am
> basically looking for more info, either from forums, other news
> groups, etc... Thank you

Smokinpope,

A few thoughts...
RFC 1490 is specific to Frame-Relay. - So I'm assuming your DS3 is
configured for frame-relay.
If you disable fragmentation, there's a possibility that packets are
being dropped due to the fact that you've told the router not to
fragment and the possibility that the packets may be too large to send
onto the next link (where the MTU could be smaller)

You'll need to provide us with a overall view of the topology - as
well as any frame-relay configurations that are applicable to the
discussion.

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