[c-nsp] 3750G packet loss
Ed Butler - RapidSwitch
ed.butler at rapidswitch.com
Fri Oct 14 13:42:33 EDT 2005
I've investigated the 3750G problem with it dropping packets to its IP
interface as below.
c3750#sh int | i Input queue: [^0]
Input queue: 1/75/0/0 (size/max/drops/flushes); Total output drops: 0
Input queue: 1/75/0/0 (size/max/drops/flushes); Total output drops: 0
show buffers old dump | in inputtime
Gives no output
Uptime is 4 weeks.
Further, I ran mtr which was giving approximately 80% loss, and whilst mtr
was pinging the router's IP interface I looked at this interface's packet
stats:
c3750#sh int vlan 211 | i Input queue:
Input queue: 1/75/147760/0 (size/max/drops/flushes); Total output drops: 0
I am concerned by the significant number of drops it has had. These do not
seem to be incrementing in line with the 80% loss that 'should' be achieved.
In fact, they don't seem to increment at all whilst I sent 20k packets to
the interface of which 4k came back.
Regards,
Ed Butler
RapidSwitch Ltd
DDI: 020 7106 0731
RapidSwitch Ltd, 5th Floor, Sovereign House, 227 Marsh Wall, London, E14 9SD
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-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Saku Ytti
Sent: 14 October 2005 11:04
To: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] 3750G packet loss
On (2005-10-14 10:14 +0100), Ed Butler - RapidSwitch wrote:
> 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.
>
> 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?
3750 has quite agressive defences against the control-plane. You can give
it's control-plane 1.4Mpps of packets and your OSPF/BGP will stay up and it
will forward packets normally.
So it might be that you have large amount of background traffic towards the
control-plane or then you might have packets stuck in hold-queue.
To investigate further please provide:
sh int | i Input queue: [^0]
show buffers old dump | in inputtime
sh ver | i uptime
>
> 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_s
> heet09
> 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
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--
++ytti
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