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New Member

Mismatched Packets TX and RX on a 100Mbits Leased Line

Can anyone throw any light on this. I have a customer that has a 100Mbits/s leased line. One end connects to a Cisco 3750 switch and the other to Cisco 3550 switch, via the provider CPE. The problem is that the 3750 is reporting different packets tx and rx load and counters than the 3550. I realise that packet counters may differ as one switch may have been up longer than the other but surely rx and tx counters should roughly match - e.g. If the tx is 250/255 on the 3750 then the rx shold be the same on the 3550. There are no errors and both ends report being reliable. I am pretty sure the line is congested and the 3750 is correct therefore could this be a bug in the 3550 IOS. See below, I have changed the switch names for privacy:

Switch A

Switch_A>sh cdp ne
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
                  D - Remote, C - CVTA, M - Two-port Mac Relay

Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
Switch_B
                 Gig 1/0/18        140             R S I  WS-C3550- Gig 0/9

Switch_A>sh inte gigabitEthernet 1/0/18
GigabitEthernet1/0/18 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 9caf.ca99.fe12 (bia 9caf.ca99.fe12)
  Description: UPLINK
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
     reliability 255/255, txload 250/255, rxload 38/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 100Mb/s, media type is 10/100/1000BaseTX
  input flow-control is off, output 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: 0/75/0/0 (size/max/drops/flushes); Total output drops: 37587
  Queueing strategy: fifo
  Output queue: 0/0 (size/max)
  5 minute input rate 15263000 bits/sec, 5215 packets/sec
  5 minute output rate 98140000 bits/sec, 8671 packets/sec
     5536992504 packets input, 1429664206845 bytes, 0 no buffer
     Received 11623350 broadcasts (8749852 multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 8749852 multicast, 0 pause input
     0 input packets with dribble condition detected
     9590687886 packets output, 13844989663615 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

SWITCH B

Switch_B>sh cdp ne
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone

Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
Switch_A
                 Gig 0/9           174          R S I     WS-C3750G Gig 1/0/18

Switch_B>sh inter gi0/9
GigabitEthernet0/9 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 000c.ce7d.a809 (bia 000c.ce7d.a809)
  Description: UPLINK
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
     reliability 255/255, txload 1/255, rxload 0/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 100Mb/s, link type is auto, media type is 10/100/1000BaseTX
  input flow-control is off, output flow-control is off
  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 2d20h
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     1982260761 packets input, 2024310630 bytes, 0 no buffer
     Received 4816462 broadcasts (0 multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 3302041 multicast, 0 pause input
     0 input packets with dribble condition detected
     1168494755 packets output, 1873130391 bytes, 0 underruns
     0 output errors, 0 collisions, 0 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

3 REPLIES
Silver

Re: Mismatched Packets TX and RX on a 100Mbits Leased Line

in switch A you can see:

Total output drops: 37587

that's why the switch retransmits again and again

also i noted we have also : output flow-control is unsupported

however it is off in switch B

New Member

Re: Mismatched Packets TX and RX on a 100Mbits Leased Line

Hi

Thanks for your response, I am still confused as to whether the 3550 is reporting the correct information or not, whether the link is congested and whether these two devices should be connected together, what should I do next?

Purple

Re: Mismatched Packets TX and RX on a 100Mbits Leased Line

  No something is not right there if the line is almost maxed out on one side  and it shows zero on the other side  unless you have like a 100 meg hub in between that has devices or something hung off of it .  Check the physical connections and make sure it is going where it says its going and not to something else that may be in that path.   Clear the counters and make sure they are actually incrementing.

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