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New Member

Port Channel input queue errors

I have a 3560 switch connected to a 6506 switch using a port channel of 2 GB. Everything appears to be configured and working correctly, however, when I do a show interface on the po interface, it shows a very large number of input and output queue drops even though utilization is very low. See partial output below. I am attaching the show interface results of the port channels on both the 6506 and the 3560 as well as the configurations of the port channels and the interfaces associated with them. The 3560 port channel interface doesn't show any drops or errors and only one of the interfaces in the port channel (54) shows drops or errors.



Port-channel54 is up, line protocol is up (connected)

Hardware is EtherChannel, address is 001d.a246.05e6 (bia 001d.a246.05e6)

Description: 2GB Uplink to STL-I9-3560-4

MTU 1500 bytes, BW 2000000 Kbit, DLY 10 usec,

reliability 255/255, txload 2/255, rxload 3/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 1000Mb/s

input flow-control is off, output flow-control is off

Members in this channel: Gi2/8 Gi3/7

ARP type: ARPA, ARP Timeout 04:00:00

Last input never, output never, output hang never

Last clearing of "show interface" counters 02:49:50

Input queue: 0/2000/16384000/0 (size/max/drops/flushes); Total output drops: 427687936

Hall of Fame Super Bronze

Re: Port Channel input queue errors

Does the 6500 connects directly to the 3560 or it goes via a patch panel ?

Have you tried replacing the patch cable ?

New Member

Re: Port Channel input queue errors

Directly connected via fiber patch. There are a couple of other switches set up the same way that have the same issue as well.

Hall of Fame Super Bronze

Re: Port Channel input queue errors

'Other switches' - are they linked to the same 6500 switch -or- other switches ?

What kind of modules do you have in the 6500 ?

Please post the show module output from this box.

New Member

Re: Port Channel input queue errors

This is just one of 24 3560s that is dual redundantly attached to 2 6506s. Every 3560 has a 2G uplink to each 6506 through direct fiber. The module is a 48 port SFP module. I am using 1,3,5, etc. on this module (3 below) and 2,4,6, etc. on a second blade (2 below). The strange thing is that it appears to only be a handful of the odd ports on just one switch that seem to be having issues.

Mod Ports Card Type Model Serial No.

--- ----- -------------------------------------- ------------------ -----------

1 24 CEF720 24 port 1000mb SFP WS-X6724-SFP SAL1101DBQH

2 48 CEF720 48 port 1000mb SFP WS-X6748-SFP SAL11402VJS

3 48 CEF720 48 port 1000mb SFP WS-X6748-SFP SAL11402VKD

4 48 SFM-capable 48 port 10/100/1000mb RJ45 WS-X6548-GE-TX SAL1103EK05

5 2 Supervisor Engine 720 (Active) WS-SUP720-3BXL SAL1101CZD6

6 2 Supervisor Engine 720 (Hot) WS-SUP720-3BXL SAL1101CWW3

Mod MAC addresses Hw Fw Sw Status

--- ---------------------------------- ------ ------------ ------------ -------

1 001a.2f68.ac18 to 001a.2f68.ac2f 2.5 12.2(14r)S5 12.2(18)SXF8 Ok

2 001d.a246.0730 to 001d.a246.075f 1.10 12.2(14r)S5 12.2(18)SXF8 Ok

3 001d.a246.05e0 to 001d.a246.060f 1.10 12.2(14r)S5 12.2(18)SXF8 Ok

4 001a.a1ef.3880 to 001a.a1ef.38af 11.1 7.2(1) 8.5(0.46)RFW Ok

5 0016.c85e.5708 to 0016.c85e.570b 5.3 8.4(2) 12.2(18)SXF8 Ok

6 0017.9568.72c4 to 0017.9568.72c7 5.3 8.4(2) 12.2(18)SXF8 Ok

Mod Sub-Module Model Serial Hw Status

---- --------------------------- ------------------ ----------- ------- -------

1 Centralized Forwarding Card WS-F6700-CFC SAD110403T9 3.1 Ok

2 Centralized Forwarding Card WS-F6700-CFC SAD11400280 4.0 Ok

3 Centralized Forwarding Card WS-F6700-CFC SAD1135062Y 4.0 Ok

5 Policy Feature Card 3 WS-F6K-PFC3BXL SAL1101CXAP 1.8 Ok

5 MSFC3 Daughterboard WS-SUP720 SAL1052CR2A 2.6 Ok

6 Policy Feature Card 3 WS-F6K-PFC3BXL SAL1052CKA9 1.8 Ok

6 MSFC3 Daughterboard WS-SUP720 SAL1052CR37 2.6 Ok

Mod Online Diag Status

---- -------------------

1 Pass

2 Pass

3 Pass

4 Pass

5 Pass

6 Pass


Re: Port Channel input queue errors

I would say this looks like some type of media problem . Port channel 54 is showing over 4 billion runts on it in less than 3 hours . Check the interfaces on the port channel for errors with the "show interface counters errors" command . Looks like the recieve side where port channel 54 is .

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