[c-nsp] Cisco 7301 limitation ?
Erik Sundberg
ESundberg at nitelusa.com
Fri Apr 21 11:39:11 EDT 2017
I have had a couple of these where CEF wasn't turned on propery on the interface and had terrible throughput and high CPU.
Check to make sure CEF is enabled on the interface.
#show cef interface g0/0
GigabitEthernet0/0 is up (if_number 2)
Corresponding hwidb fast_if_number 2
Corresponding hwidb firstsw->if_number 2
Internet Protocol processing disabled
Hardware idb is GigabitEthernet0/0
Fast switching type 1, interface type 27
IP CEF switching enabled <<<<<<<<<
IP CEF switching turbo vector
IP CEF turbo switching turbo vector
IP prefix lookup IPv4 mtrie 8-8-8-8 optimized
Input fast flags 0x20080000, Output fast flags 0x8004008
ifindex 2(2)
Slot Slot unit 0 VC -1
IP MTU 0
Also we are running Version 15.2(4)S7 just fine on our 7301.
You can check to see what is being punted to the cpu via.
#show cef not-cef-switched
% Command accepted but obsolete, see 'show (ip|ipv6) cef switching statistics [feature]'
IPv4 CEF Packets passed on to next switching layer
Slot No_adj No_encap Unsupp'ted Redirect Receive Options Access Frag
RP 0 0 1027549 307 6222801 0 0 0
IPv6 CEF Packets passed on to next switching layer
Slot No_adj No_encap Unsupp'ted Redirect Receive Options Access MTU
RP 0 0 1794368 0 988337 0 0 0
#show ip cef switching statistics
Path Reason Drop Punt Punt2Host
RP LES Packet destined for us 0 3111368 0
RP LES Neighbor resolution req 0 30 0
RP LES Total 0 3111398 0
RP PAS No route 121 0 31
RP PAS Packet destined for us 0 3111368 359
RP PAS No adjacency 867 0 0
RP PAS Incomplete adjacency 2174690 0 0
RP PAS TTL expired 0 0 1027232
RP PAS Routed to Null0 26 0 201
RP PAS IP redirects 0 0 307
RP PAS Unclassified reason 259 0 0
RP PAS Neighbor resolution req 172650 0 0
RP PAS Bad IP packet header leng 1346 0 0
RP PAS Link-layer broadcast/mult 11057 0 0
RP PAS Total 2361016 3111368 1028130
All Total 2361016 6222766 1028130
-----Original Message-----
From: cisco-nsp [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Arie Vayner
Sent: Thursday, April 20, 2017 5:00 PM
To: Bill Blackford; Olivier CALVANO
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] Cisco 7301 limitation ?
Even though it is a software router, there's a difference if packets are forwarded on the fast path or slow path (punt).
Arie
On Thu, Apr 20, 2017 at 2:49 PM Bill Blackford <bblackford at gmail.com> wrote:
> It is a software router. I've had these fall over from too many small
> packets.
>
> Sent from my iPhone
>
> > On Apr 20, 2017, at 13:07, Arie Vayner <ariev at vayner.net> wrote:
> >
> > I would check for MTU and fragmentation issues... If the router is
> > fragmenting, it would bring the CPU up...
> >
> > On Thu, Apr 20, 2017 at 10:41 AM Olivier CALVANO
> > <o.calvano at gmail.com>
> > wrote:
> >
> >> Hi
> >>
> >> i have a problems with a cisco 7301 IOS:
> >>
> >> Cisco IOS Software, 7301 Software (C7301-ADVENTERPRISEK9-M),
> >> Version 12.2(33)SRD5, RELEASE SOFTWARE (fc2)
> >>
> >> No special config on C7301, no qos, no access list, no filter ...
> >> only
> IP
> >> Route
> >>
> >>
> >>
> >> On this router, i have two ports used:
> >> GigabitEthernet0/0
> >> GigabitEthernet0/1
> >>
> >> Port 0/0 it's a 1 Gbits link
> >> Port 0/1 it's a 1 Gbits link but i two vlan each vlan is a fiber
> >> remote link, one of 20Mbits and the second 500 Mbits
> >>
> >>
> >> When i start a upload from a pc behind the 500 Mbits vlan link, no
> >> problems, i have 500 Mbits and cpu is good:
> >> CPU utilization for five seconds: 33%/22%
> >>
> >>
> >>
> >> but when i download, i am limited to 266 Mbits and the CPU of the
> >> C7301
> are
> >> high:
> >>
> >> CPU utilization for five seconds: 98%/43%
> >>
> >>
> >> anyone know this problems ?
> >>
> >> It's possible because the cisco don't know that the vlan is limited
> >> at
> 500
> >> mbits and he want sent at 1 gbits ?
> >>
> >> regards
> >> Olivier
> >> _______________________________________________
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