QOS Question - Showing 1,000,000 discards per day

Unanswered Question

I have a DS3 terminated with 7206VXR-GE2 on each end. The circuit is purely to replicate traffic between 2 systems. So there are basically only 2 hosts and 1 protocol. What can I do to help reduce or eliminate all of these discards. I have no QOS on the circuit. Would shaping help signal the sending host to slow down and reduce these discards?

Thank you for your help.

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royalblues Thu, 04/03/2008 - 08:14
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Is there any problem you are facing with the replication or you are just interested in the getting rid of the discards?

If you do configure shaping, you will not see the discards but it is quite possible that they show up as delayed bytes.

what is the IOS you are running?


Joseph W. Doherty Thu, 04/03/2008 - 17:03
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Can you post the interface stats where you see these discards?

Serial1/0 is up, line protocol is up

Hardware is M1T-T3+ pa

Description: DS3 Circuit

Internet address is

MTU 4470 bytes, BW 44210 Kbit, DLY 200 usec,

reliability 255/255, txload 3/255, rxload 1/255

Encapsulation PPP, LCP Open

Listen: CDPCP

Open: IPCP, crc 16, loopback not set

Keepalive set (10 sec)

Restart-Delay is 0 secs

Last input 00:00:00, output 00:00:00, output hang never

Last clearing of "show interface" counters 3d03h

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 2354497

Queueing strategy: weighted fair

Output queue: 0/1000/64/2354497 (size/max total/threshold/drops)

Conversations 0/72/256 (active/max active/max total)

Reserved Conversations 0/0 (allocated/max allocated)

Available Bandwidth 44210 kilobits/sec

5 minute input rate 223000 bits/sec, 314 packets/sec

5 minute output rate 602000 bits/sec, 324 packets/sec

208856856 packets input, 1621576644 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

0 parity

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

261926945 packets output, 1797784893 bytes, 0 underruns

0 output errors, 0 applique, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

rxLOS inactive, rxLOF inactive, rxAIS inactive

txAIS inactive, rxRAI inactive, txRAI inactive

Joseph W. Doherty Thu, 04/03/2008 - 17:48
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Total output drops: 2354497

261926945 packets output

About .9% drop. That normally isn't considered that bad if the link is being filled.

I see Queueing strategy: weighted fair. How is the interface configured to obtain WFQ?

In this snapshot of interface stats, the interface isn't very active. Have you seen it at much higher load rates?

What's the CPU history like? (show proc cpu history - supported?)

What do your buffer stats look like? (show buffers)


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