Need some help. I have a 7206 router with a DS3 serial link on one port. I have noticed quite often that when the input rate on the link is at the maximum the rxload figure is low, eg. 19/255 rather that closer to 255/255. I am also using mrtg to monitor bandwidth usage. Mrtg also shows the usage at around 3Mb/s when it should be around 45Mb/s. I am using IOS 12.1(4) Enterprise edition. Has anyone encountered any similar problem?
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7206 rxload question
- Thread starter PuppetX
- Start date
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- #3
Here's the output:
router>sh int s2/0
Serial2/0 is up, line protocol is up
Hardware is M1T-T3 pa
Description: XXXX DS3 XXXX
Internet address is xxx.xxx.xxx.xxx/xx
MTU 4470 bytes, BW 44210 Kbit, DLY 200 usec,
reliability 255/255, txload 39/255, rxload 3/255
Encapsulation HDLC, crc 16, loopback not set
Keepalive set (10 sec)
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 1/75/7974/2136181 (size/max/drops/flushes); Total output drops: 18511
Queueing strategy: weighted fair
Output queue: 0/1000/64/4 (size/max total/threshold/drops)
Conversations 0/9/256 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
5 minute input rate 44943000 bits/sec, 8621 packets/sec
5 minute output rate 6871000 bits/sec, 4993 packets/sec
1456998274 packets input, 3161001372 bytes, 49 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 parity
188 input errors, 89 CRC, 0 frame, 89 overrun, 0 ignored, 10 abort
75047 packets output, 1801128 bytes, 388 underruns
388 output errors, 0 applique, 2 interface resets
0 output buffer failures, 0 output buffers swapped out
9 carrier transitions
rxLOS inactive, rxLOF inactive, rxAIS inactive
txAIS inactive, rxRAI inactive, txRAI inactive
As you can see the input rate is around 100% but the rxload is 3/255. MRTG is also reporting the input rate as around 2MB/s.
router>sh int s2/0
Serial2/0 is up, line protocol is up
Hardware is M1T-T3 pa
Description: XXXX DS3 XXXX
Internet address is xxx.xxx.xxx.xxx/xx
MTU 4470 bytes, BW 44210 Kbit, DLY 200 usec,
reliability 255/255, txload 39/255, rxload 3/255
Encapsulation HDLC, crc 16, loopback not set
Keepalive set (10 sec)
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 1/75/7974/2136181 (size/max/drops/flushes); Total output drops: 18511
Queueing strategy: weighted fair
Output queue: 0/1000/64/4 (size/max total/threshold/drops)
Conversations 0/9/256 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
5 minute input rate 44943000 bits/sec, 8621 packets/sec
5 minute output rate 6871000 bits/sec, 4993 packets/sec
1456998274 packets input, 3161001372 bytes, 49 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 parity
188 input errors, 89 CRC, 0 frame, 89 overrun, 0 ignored, 10 abort
75047 packets output, 1801128 bytes, 388 underruns
388 output errors, 0 applique, 2 interface resets
0 output buffer failures, 0 output buffers swapped out
9 carrier transitions
rxLOS inactive, rxLOF inactive, rxAIS inactive
txAIS inactive, rxRAI inactive, txRAI inactive
As you can see the input rate is around 100% but the rxload is 3/255. MRTG is also reporting the input rate as around 2MB/s.
This is the Cisco Output Interpreter for you command. If you have privileged access to CCO the link is:
If you do not have privileged access to CCO, clear the counters, as suggested, and post a new "sh interface" in half an hour that I will execute the application for you.
Output Interpreter analysis:
You have chosen to display errors warnings general information, and helpful references.
Headings are displayed for all supported commands that you submitted.
SHOW INTERFACE SERIAL Analysis
Back to top
==========================================================================
SHOW INTERFACE SERIAL NOTIFICATIONS (if any)
==========================================================================
Interface Serial2/0 (up/up)
WARNING: The counters have never been cleared for this interface.
TRY THIS: Use the 'clear counters Serial2/0' command to ensure
current information is being displayed. This will assist when troubleshooting
serial interface issues.
WARNING: This interface has a high number of output drops.
The input rate to this interface has exceeded the bandwidth available on the
serial link.
TRY THIS:
1. Minimize periodic broadcast traffic like routing and Service Advertising
Protocol (SAP) updates (if applicable) by using access lists or by other
means.
2. Turn off fast switching for heavily used protocols. For example, turn off
IP fast switching by using the 'no ip route-cache' interface configuration
command.
3. Implement priority queuing on slower serial links.
4. Submit the output from 'show buffers' to Output Interpreter to determine if
buffers need to be tuned.
REFERENCE: For more information see: Troubleshooting Output Drops
WARNING: This interface has had 9 carrier transitions.
TRY THIS: Use the 'clear counters Serial2/0' command to ensure
current information is being displayed. Check interface resets as well. If
they are high while carrier transitions are being registered, the problem is
most likely a bad link or CSU/DSU. Contact your service provider and swap
faulty equipment as necessary.
REFERENCE: For more information see: HDLC Back to Back Connections
WARNING: This interface has had 2 interface resets.
TRY THIS: Use the 'clear counters Serial2/0' command to ensure
current information is being displayed. Check carrier transitions as well. If
they are high while interface resets are being registered, the problem is most
likely a bad link or CSU/DSU. Contact your service provider and swap faulty
equipment as necessary.
REFERENCE: For more information see: Troubleshooting Serial Lines
WARNING: 49 packets have been dropped because there were no free buffers
to copy the packet.
TRY THIS: If this is incrementing, paste the output from the 'show buffers'
command into Output Interpreter to see if the buffers can be tuned. Also
compare with the 'ignored' counter and input/output queue drops. Broadcast
storms and bursts of noise on serial lines are often responsible for no buffer
events.
REFERENCE: For more information see:
Buffer Tuning
Troubleshooting Input and Output Queue Drops
INFO: You have 2136181 recorded flushes for this interface. Flushes are
similar to input drops, but are proactively forced by the router before the
input queue is full. Selective Packet Discard (SPD) is the congestion
avoidance mechanism used, where non-control packets are dropped in preference
to control packets (i.e. routing updates). Monitor the number of flushes. If
they continue to increment, you should consider increasing the size of the
input queue and/or improving the switching mechanism used by this interface
(e.g. change process switching to fast switching). You can troubleshoot
flushes in a similar manner to input drops.
REFERENCE: For more information see: Troubleshooting Input Drops
REFERENCE: For more information on Serial Lines, see:
Troubleshooting Serial Line Problems
Configuring Serial Interfaces
Troubleshooting Serial Lines
Troubleshooting Leased Lines
Loopback Tests for T1/56K Lines
REFERENCE: For more information on this command, see: 'show interface serial'
If you do not have privileged access to CCO, clear the counters, as suggested, and post a new "sh interface" in half an hour that I will execute the application for you.
Output Interpreter analysis:
You have chosen to display errors warnings general information, and helpful references.
Headings are displayed for all supported commands that you submitted.
SHOW INTERFACE SERIAL Analysis
Back to top
==========================================================================
SHOW INTERFACE SERIAL NOTIFICATIONS (if any)
==========================================================================
Interface Serial2/0 (up/up)
WARNING: The counters have never been cleared for this interface.
TRY THIS: Use the 'clear counters Serial2/0' command to ensure
current information is being displayed. This will assist when troubleshooting
serial interface issues.
WARNING: This interface has a high number of output drops.
The input rate to this interface has exceeded the bandwidth available on the
serial link.
TRY THIS:
1. Minimize periodic broadcast traffic like routing and Service Advertising
Protocol (SAP) updates (if applicable) by using access lists or by other
means.
2. Turn off fast switching for heavily used protocols. For example, turn off
IP fast switching by using the 'no ip route-cache' interface configuration
command.
3. Implement priority queuing on slower serial links.
4. Submit the output from 'show buffers' to Output Interpreter to determine if
buffers need to be tuned.
REFERENCE: For more information see: Troubleshooting Output Drops
WARNING: This interface has had 9 carrier transitions.
TRY THIS: Use the 'clear counters Serial2/0' command to ensure
current information is being displayed. Check interface resets as well. If
they are high while carrier transitions are being registered, the problem is
most likely a bad link or CSU/DSU. Contact your service provider and swap
faulty equipment as necessary.
REFERENCE: For more information see: HDLC Back to Back Connections
WARNING: This interface has had 2 interface resets.
TRY THIS: Use the 'clear counters Serial2/0' command to ensure
current information is being displayed. Check carrier transitions as well. If
they are high while interface resets are being registered, the problem is most
likely a bad link or CSU/DSU. Contact your service provider and swap faulty
equipment as necessary.
REFERENCE: For more information see: Troubleshooting Serial Lines
WARNING: 49 packets have been dropped because there were no free buffers
to copy the packet.
TRY THIS: If this is incrementing, paste the output from the 'show buffers'
command into Output Interpreter to see if the buffers can be tuned. Also
compare with the 'ignored' counter and input/output queue drops. Broadcast
storms and bursts of noise on serial lines are often responsible for no buffer
events.
REFERENCE: For more information see:
Buffer Tuning
Troubleshooting Input and Output Queue Drops
INFO: You have 2136181 recorded flushes for this interface. Flushes are
similar to input drops, but are proactively forced by the router before the
input queue is full. Selective Packet Discard (SPD) is the congestion
avoidance mechanism used, where non-control packets are dropped in preference
to control packets (i.e. routing updates). Monitor the number of flushes. If
they continue to increment, you should consider increasing the size of the
input queue and/or improving the switching mechanism used by this interface
(e.g. change process switching to fast switching). You can troubleshoot
flushes in a similar manner to input drops.
REFERENCE: For more information see: Troubleshooting Input Drops
REFERENCE: For more information on Serial Lines, see:
Troubleshooting Serial Line Problems
Configuring Serial Interfaces
Troubleshooting Serial Lines
Troubleshooting Leased Lines
Loopback Tests for T1/56K Lines
REFERENCE: For more information on this command, see: 'show interface serial'
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