[c-nsp] 3750G packet loss

Saku Ytti saku+cisco-nsp at ytti.fi
Fri Oct 14 13:53:45 EDT 2005 

On (2005-10-14 18:42 +0100), Ed Butler - RapidSwitch wrote:

> 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

Good, there are no stuck packets.

> 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.

 Then I think we need to establish if you're forwarding packets in
hardware or not. 'show sdm prefer' are you exceeding any of these 
values? 'show proc cpu' do you have high I/O load? If both answers
are 'no' then you actually might want to see what the router is processing
in CPU 'debug ip packet <acl-to-ignore-your-telnet-session>', I find it
best to log to syslog rather than terminal monitor, but YMMV. Some caution
should be excericed with 'debug ip packet'.

> 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
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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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-- 
  ++ytti

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