[c-nsp] Troubleshooting Lag between GigE interfaces

[Paul Stewart]

Anyone have the commands or cisco doc on properly setting up flow
control on the 7513 and 6509?

Thanks,

Paul


On Wed, 2004-09-22 at 17:02, Deepak Jain wrote:
> I would increase the size of the hold-queue "input" and see what happens 
> after you clear the counters. You are definitely exhausting the input 
> buffer on the 7513. The question is whether its just burstiness or 
> something else -- you don't seem to be moving very much traffic on it to 
> be a CPU issue. You do have output flow control on the 6509 on, but 
> don't have the same setting on the 7513. That is the big problem I'd guess.
> 
> Paul Stewart wrote:
> 
> > We have a 7513 and a 6509 connected via GigE SX Fiber.  Frequently we
> > see "lag" on the connection lasting 5-10 seconds causing 60-80ms delay.
> > 
> > When I look at the interfaces I see the following:
> > 
> > 7513
> > 
> > GigabitEthernet8/1/0 is up, line protocol is up
> >   Hardware is cyBus GigabitEthernet Interface, address is 0001.64ef.a108
> > (bia 0001.64ef.a108)
> >   Description: Gig Fiber to 6509
> >   Internet address is XXX.XXX.XXX.XXX/24
> >   MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
> >      reliability 255/255, txload 8/255, rxload 6/255
> >   Encapsulation ARPA, loopback not set
> >   Keepalive set (10 sec)
> >   Full-duplex, 1000Mb/s, link type is autonegotiation, media type is SX
> >   output flow-control is XOFF, input flow-control is unsupported
> >   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 never
> >   Input queue: 3/75/913188/2076260 (size/max/drops/flushes); Total
> > output drops: 0
> >   Queueing strategy: fifo
> >   Output queue: 0/40 (size/max)
> >   30 second input rate 26395000 bits/sec, 9394 packets/sec
> >   30 second output rate 35145000 bits/sec, 9900 packets/sec
> >      1790737826 packets input, 2276828279 bytes, 0 no buffer
> >      Received 1895463 broadcasts, 0 runts, 0 giants, 34543 throttles
> >      0 input errors, 0 CRC, 0 frame, 36 overrun, 0 ignored
> >      0 watchdog, 520626 multicast, 0 pause input
> >      0 input packets with dribble condition detected
> >      1655202857 packets output, 359511296 bytes, 0 underruns
> >      0 output errors, 0 collisions, 0 interface resets
> >      0 babbles, 0 late collision, 0 deferred
> >      2 lost carrier, 0 no carrier, 0 pause output
> >      0 output buffer failures, 0 output buffers swapped out
> > 
> > 6509
> > 
> > GigabitEthernet1/2 is up, line protocol is up (connected)
> >   Hardware is C6k 1000Mb 802.3, address is 0006.d65b.853d (bia
> > 0006.d65b.853d)
> >   Description: Connection to 7513
> >   MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
> >      reliability 255/255, txload 8/255, rxload 11/255
> >   Encapsulation ARPA, loopback not set
> >   Full-duplex, 1000Mb/s, media type is SX
> >   input flow-control is off, output flow-control is on
> >   Clock mode is auto
> >   ARP type: ARPA, ARP Timeout 04:00:00
> >   Last input never, output never, output hang never
> >   Last clearing of "show interface" counters never
> >   Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops:
> > 0
> >   Queueing strategy: fifo
> >   Output queue: 0/40 (size/max)
> >   5 minute input rate 43500000 bits/sec, 12035 packets/sec
> >   5 minute output rate 33545000 bits/sec, 11573 packets/sec
> >      5952975396 packets input, 2640933868846 bytes, 0 no buffer
> >      Received 1696859 broadcasts (68504 multicast)
> >      0 runts, 0 giants, 0 throttles
> >      0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
> >      0 watchdog, 0 multicast, 0 pause input
> >      0 input packets with dribble condition detected
> >      6088478711 packets output, 2200836239462 bytes, 0 underruns
> >      0 output errors, 0 collisions, 1 interface resets
> >      0 babbles, 0 late collision, 0 deferred
> >      0 lost carrier, 0 no carrier, 0 PAUSE output
> >      0 output buffer failures, 0 output buffers swapped out
> > 
> > The 6509 looks nice and clean but the 7513 shows a tonne of buffer
> > issues it seems.  Is this a buffer issue that I should start trying to
> > tune or would something else be the actual cause do you think?
> > 
> > Thanks in advance,
> > 
> > Paul
> > 
> > 
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