[c-nsp] 3750G packet loss

Fri Oct 14 05:14:49 EDT 2005

We've got a stack of Cisco 3750Gs (EMI image) acting as an OSPF router.
They're coping brilliantly, aside from some odd behaviour. 

They seem to be dropping ICMP packets destined for themselves very
frequently. The easiest way to illustrate this was to run mtr (a
traceroute/ping application) as quickly as possible between two points on
the network that traverse the 3750 stack.

To be clear on this, the 3750s are forwarding traffic 100% correctly with no
loss, however they're not dealing with traffic to themselves very well.
They're not stressed either, running ~10% CPU usage.

I've run mtr for 10 seconds where it averaged ~120 ICMP echo/replies to the
test host on the network. Here are the results:

                  Packets               Pings
 Host          Loss%   Snt   Last   Avg  Best  Wrst StDev
 1. cisco3750  81.6%  1227    0.4   0.5   0.3   2.7   0.3
 2. linuxhost   0.0%  1227    0.2   0.2   0.1  16.2   1.7

Does anyone have any experience with a similar problem or situation, and can
advise how to deal with it?

Thanks,

Regards,

Ed Butler
RapidSwitch Ltd
DDI: 020 7106 0731

RapidSwitch Ltd, 5th Floor, Sovereign House, 227 Marsh Wall, London, E14 9SD

This email message is intended only for the addressee(s) and contains
information that may be confidential and/or copyright.  If you are not the
intended recipient please notify the sender by reply email and immediately
delete this email. Use, disclosure or reproduction of this email by anyone
other than the intended recipient(s) is strictly prohibited. No
representation is made that this email or any attachments are free of
viruses. Virus scanning is recommended and is the responsibility of the
recipient. 
-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Richard Gallagher
Sent: 14 October 2005 10:04
To: Maxim Tuliuk
Cc: Asbjorn Hojmark - Lists; cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] software upgrade 3750 to 3750 Metro

From:

http://www.cisco.com/en/US/products/hw/switches/ps5532/products_data_sheet09
186a00801eb820.html

The Enhanced Services ports support enhanced features such as Hierarchical
QoS and Traffic Shaping, intelligent 802.1Q tunneling, VLAN translation,
MPLS, and EoMPLS. These ports can serve as uplinks to metro aggregation
points, including the Cisco Catalyst 4500 and Catalyst 6500 series and the
Cisco 7600 Series, and they provide greater intelligence at the network
edge.

The regular cat3750 does not have the same ES ports avialable to enable
these extra features.

HTH, Ric

Maxim Tuliuk wrote:
> On Fri, Oct 14, 2005 at 10:26 +0200, Asbjorn Hojmark - Lists wrote:
>>> Can I do upgrade from 3750 to 3750 Metro?  If yes how?
>> No.
>>
>> The 3750ME has a small PXF router onboard, so it's simply not the 
>> same hardware.
> 
> Is it official or unofficial information? i.e I didn't find about it 
> on cisco site
_______________________________________________
cisco-nsp mailing list  cisco-nsp at puck.nether.net
https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/