influence of deferred packet counter on performance

gerd.steinhauer · ‎06-26-2002

when looking on interface statistics of a GE-PA in a 7206 there are the following statistics upcounting:

sh int giga 2/0

GigabitEthernet2/0 is up, line protocol is up

Hardware is WISEMAN, address is 0002.4a8f.0838 (bia 0002.4a8f.0838)

Description: *** GE-Interface, connected to SW RZ-2 (HSRP fuer Group 1+2)

***

Internet address is 10.9.1.2/16

MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

reliability 255/255, txload 4/255, rxload 6/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex mode, link type is autonegotiation, media type is SX

output flow-control is on, input flow-control is on

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 13:52:37

Queueing strategy: fifo

Output queue 0/100, 0 drops; input queue 1/400, 1828 drops

30 second input rate 24632000 bits/sec, 4516 packets/sec

30 second output rate 17464000 bits/sec, 3533 packets/sec

60930355 packets input, 3620247183 bytes, 8 no buffer

Received 2470219 broadcasts, 0 runts, 0 giants, 1836 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 111170 multicast, 0 pause input

0 input packets with dribble condition detected

43491409 packets output, 1304892066 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 babbles, 0 late collision, 1059386 deferred

0 lost carrier, 0 no carrier, 0 pause output

0 output buffer failures, 0 output buffers swapped out

are there any influences of the "1059386 deferred" counter on router-performance?

what does the router exactly mean by "deferred"

Prashanth Krishnappa · ‎06-27-2002

The following page on CCO should answer your question

http://www.cisco.com/warp/public/63/eth_collisions.html#deferred

rjackson · ‎08-30-2002

This is a full duplex link and should not be doing any carrier sensing to result in deferred packets. I'm having the same problem on 36xx routers and found a bug report, CSCds19771 that says its an auto-negotiation problem. That bug is 36xx specific but it looks like the problem may be more general. It wouldnt be hard to set it to not negotiate and see if the deferrals stop.

What I'm trying to figure out is whether the bug has anything to do with dropped packets that I'm seeing on my 36xxs. They dont show up on any other counters but packets are getting dropped. I have not been able to schedule the outage to change the config on the interfaces even though tests show the interface will only be down for 2-3 seconds.