12-24-2014 09:09 AM - edited 03-07-2019 10:00 PM
Seeing a lot of dropped packets on my Serial interface. This is a single point to point T1.The outgoing line is not being over utilized. I see the issue is with the buffer, as they equal the number of dropped packets. Is it possible to increase memory on this router to increase buffer space for these packets?
Running c2900-universalk9-mz.SPA.151-2.T5 code.
sh int s0/0/0:0
Serial0/0/0:0 is up, line protocol is up
Hardware is DSX1
Description: MGBK1WR70001
Internet address is 10.221.254.245/24
MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation HDLC, crc 16, loopback not set
Keepalive set (10 sec)
Last input 00:00:08, output 00:00:02, output hang never
Last clearing of "show interface" counters 2d01h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 6967
Queueing strategy: weighted fair
Output queue: 0/1000/64/6967 (size/max total/threshold/drops)
Conversations 0/44/256 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 1158 kilobits/sec
1 minute input rate 3000 bits/sec, 1 packets/sec
1 minute output rate 4000 bits/sec, 1 packets/sec
765505 packets input, 258750698 bytes, 6967 no buffer
Received 17798 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
800062 packets output, 310933109 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
Configuration:
interface Serial0/0/0:0
description MGBK1WR70001
bandwidth 1544
ip address X.X.X.X
no ip redirects
no ip unreachables
no ip proxy-arp
ip flow ingress
ip traffic-export apply r04 size 10000000
load-interval 60
fair-queue
no cdp enable
Solved! Go to Solution.
12-24-2014 09:32 AM
For testing, can you delete these commands:
ip traffic-export apply r04 size 10000000
fair-queue
than clear the counters and monitor again for packet drops?
HTH
12-24-2014 09:32 AM
For testing, can you delete these commands:
ip traffic-export apply r04 size 10000000
fair-queue
than clear the counters and monitor again for packet drops?
HTH
12-24-2014 09:55 AM
I just added the fair-queue statement and haven't seen a dropped packet yet. The export command was added to try and alleviate the issue previously. Are you looking for a different error by removing these 2 commands? I can assure you it will be the same.
12-31-2014 05:10 AM
Still dropping packets after removing the 2 lines stated above.
GHSBEA1-R04#sh int s0/0/0:0
Serial0/0/0:0 is up, line protocol is up
Hardware is DSX1
Description: MGBK1WR70001
Internet address is 10.221.254.245/24
MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 4/255, rxload 3/255
Encapsulation HDLC, crc 16, loopback not set
Keepalive set (10 sec)
Last input 00:00:06, output 00:00:00, output hang never
Last clearing of "show interface" counters 6d20h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 20950
Queueing strategy: weighted fair
Output queue: 0/1000/64/20950 (size/max total/threshold/drops)
Conversations 0/5/256 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 1158 kilobits/sec
1 minute input rate 23000 bits/sec, 10 packets/sec
1 minute output rate 28000 bits/sec, 11 packets/sec
1418269 packets input, 561315415 bytes, 20950 no buffer
Received 58840 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
1457808 packets output, 634520576 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
Do I need more memory on this router or just a more robust router? Seems the traffic is very bursty, it trickles in most of the time and then ti has a large surge and packets get dropped.
12-31-2014 06:45 AM
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The issue might be mitigate with buffer tuning. What do you buffer stats look like?
(BTW, don't know if it applies to 15.x code, but there's also a buffer auto tune option.)
12-31-2014 06:54 AM
We did run the auto-tuning on the switch.
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