[c-nsp] Input Queue 7500
Rodney Dunn
rodunn at cisco.com
Thu Dec 28 12:17:39 EST 2006
It's a long email to explain in detail so let's just start simple:
'sh run' of the interfaces that this traffic is coming in and going
out of.
clear count
and get 'sh int stat' every 30 seconds for 2 minutes so we can see
what % is being process switched. Get 'sh cef int' and 'sh ip int'
for all interfaces.
What type of traffic is it? internet? etc...?
On Wed, Dec 27, 2006 at 06:11:11PM -0500, omar parihuana wrote:
> Thanks Anton for your reply.
>
> CEF is enable (ip cef global configuration command is configured):
>
> R#show interfaces switching
> FastEthernet4/1/0
> Throttle count 8
> Drops RP 491 SP 0
> SPD Flushes Fast 2561 SSE 0
> SPD Aggress Fast 0
> SPD Priority Inputs 0 Drops 0
>
> Protocol Path Pkts In Chars In Pkts Out Chars Out
> Other Process 0 0 436870 26212200
> Cache misses 0
> Fast 0 0 0 0
> Auton/SSE 0 0 0 0
> IP Process 2226190620 2002650219 2393235708 2822177457
> Cache misses 623
> Fast 1763768067 234570619 1779057481 4136533720
> Auton/SSE 0 0 0 0
> DEC MOP Process 0 0 7270 559790
> Cache misses 0
> Fast 0 0 0 0
> Auton/SSE 0 0 0 0
>
> Also, I enable ip route-cache flow in this interface because there is a long
> access-list (in accordance to suggestion the previous link -the drops and
> flash increase slower than without the ip route-cache flow) Currently the
> 7513 is attached to Black Box (Allied Telesin Switch, that unfortunately, I
> don't have admin) is possible that Allied Telesin Switch cause this input
> queue drops, because the low performance of Allied, sometimes the CPU
> processor reach 80% too.
>
> 7513-118.1#sh cef drop
> CEF Drop Statistics
> Slot Encap_fail Unresolved Unsupported No_route No_adj ChkSum_Err
> RP 3747 0 656 32 0 0
> 7513-118.1#
>
> So far, unfortunately, the counter is increasing...
>
> Input queue: 56/75/247/178 (size/max/drops/flushes); Total output drops: 0
>
> Thanks!!
>
> Rgds.
>
>
> On 12/27/06, Anton Kapela <tk at 5ninesdata.com> wrote:
> >
> >
> >
> > > I've noticed the input queue interface ethernet from my 7513
> > > (drops and flushes is increasing)
> >
> > That counter doesn't mean what Cisco lets you think it means....
> >
> > > Encapsulation ARPA, loopback not set
> > > Keepalive set (10 sec)
> > > Full-duplex, 100Mb/s, 100BaseTX/FX
> > > ARP type: ARPA, ARP Timeout 04:00:00
> > > Last input 00:00:00, output 00:00:00, output hang never
> > > Last clearing of "show interface" counters 00:35:20
> > > Input queue: 5/75/1053/6148 (size/max/drops/flushes); Total
> > > output drops:
> > > 0 <<<<< SEE HERE!
> >
> > > This behavior is normal, for that traffic (About 45Mbps in
> > > some cases) ???
> >
> > That should not be observed unless you're: running cef-less, being
> > directly attacked, or attached to noisy-ass layer-2 that faces, oh, say,
> > a few thousand collocation customers with 50 or 60 ip address
> > secondary's configured. Any of those situations could be causing what
> > you're seeing, and let me be clear: none of them would be characterized
> > as normal.
> >
> > > How can I decrease that counters? some suggestions for set up
> > > in Ethernet Interface???
> >
> > First of all, 'sh int' input queue is a depiction of the state of
> > packets which were placed into queue for the "ip_input" process; i.e.
> > these are packets waiting to be "process switched." This is generally
> > bad. Before you go any further in troubleshooting this, check to ensure
> > that cef is enabled on your router.
> >
> > If it is, then start debugging and checking your switching path. You can
> > do this by becoming more familiar with the 7500 switching architecture.
> > I'd suggest the following URLs to get yourself started:
> >
> > 1) http://tinyurl.com/7fw4p
> >
> > Be sure to focus on this part of the page:
> >
> > 2) http://tinyurl.com/wg8qz
> >
> >
> > Also, use the following commands on interfaces which you're seeing the
> > input queue drops on:
> >
> > #sh int FastEthernet3/0/0 switching
> >
> > #sh int FastEthernet3/0/0 stats
> >
> > #sh int FastEthernet3/0/0 accounting
> >
> > In a nutshell, when you see actual ip_input queue drops (which is what
> > the 'sh int' is displaying), things are "not good."
> >
> > Any protocol which requires RSP/RP attention must be punted to the host
> > processor. This includes stuff like certain layer-2 ethertype
> > broadcasts, ARP, BFD, OSPF Hellos, certain other multicast, DHCP, and
> > CDP, in addition to packets directly addressed to the routers interfaces
> > or control plane. If cef is disabled entirely on your box, then this
> > counter will be including buffered packets about to be switched, which
> > it normally (when cef is running) would not.
> >
> > You can get a feel for what protocol 'groups' are listening (read:
> > configuring cef to punt packets up to the host rsp/rp) on an interface
> > by looking at the routers hardware & software IDB allocation. To see it,
> > use:
> >
> > #sh idb
> >
> > [snip]
> >
> > HWIDB#1 Serial1/0/0:1 (HW IFINDEX(10001), HW SB CDP(4), Serial(3), MAC
> > ADDR(1))
> > HWIDB#2 Serial1/0/0:2 (HW IFINDEX(10001), HW SB CDP(4), Serial(3), MAC
> > ADDR(1))
> > HWIDB#3 Serial1/0/0:3 (HW IFINDEX(10001), HW SB CDP(4), Serial(3), MAC
> > ADDR(1))
> > [snip]
> >
> > SWIDB#1 Serial1/0/0:1 (SW CDP(4), NetBIOS(2), DSS(3), KEEPALIVE(1))
> > SWIDB#2 Serial1/0/0:2 (SW CDP(4), NetBIOS(2), DSS(3), KEEPALIVE(1))
> > SWIDB#3 Serial1/0/0:3 (SW CDP(4), NetBIOS(2), DSS(3), KEEPALIVE(1))
> > [snip]
> >
> > Good luck,
> >
> > -Tk
> >
>
>
>
> --
> Omar E.P.T
> -----------------
> Certified Networking Professionals make better Connections!
>
> http://omarept.blogspot.com/
>
> Usysnet Corp
> Open Source Solutions
> www.usysnet.com.pe
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