Counter Tx-Drops-Queue-1 drops on trunk

vgaraboa · ‎11-27-2008

Hi.

I have a 4506 with a trunk port.

In this port I can see that the counter:

Tx-Drops-Queue-1 have 5669 packets drops.

The trunk is with an HP switch, the config of vlans in trunk included native is ok.

I see the buffers and I think is ok:

Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 9845

Queueing strategy: fifo

Output queue: 0/40 (size/max)

Any ideas of the "why" of this drops?

Thanks in advance.

Victor.

mihanlin · ‎11-27-2008

Hi,

It looks like you might have QoS enabled, and queue 1 is showing drops.

You will need to check the "sh qos maps" command to see what dscp and cos values are mapped to queue 1. This will give you an idea on what kinds of traffic is being sent to the first queue.

Michael.

vgaraboa · ‎11-27-2008

Thanks Michael.

In fact QoS is enabled (by default):

QoS is enabled globally

IP header DSCP rewrite is enabled

When I put "sh qos maps" I see these values, but I haven't a lot of experience QoS, have a good link to read about?

d1 : d2 0 1 2 3 4 5 6 7 8 9

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

0 : 01 01 01 01 01 01 01 01 01 01

1 : 01 01 01 01 01 01 02 02 02 02

2 : 02 02 02 02 02 02 02 02 02 02

3 : 02 02 03 03 03 03 03 03 03 03

4 : 03 03 03 03 03 03 03 03 04 04

5 : 04 04 04 04 04 04 04 04 04 04

6 : 04 04 04 04

Policed DSCP Mapping Table (dscp = d1d2)

d1 : d2 0 1 2 3 4 5 6 7 8 9

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

0 : 00 01 02 03 04 05 06 07 08 09

1 : 10 11 12 13 14 15 16 17 18 19

2 : 20 21 22 23 24 25 26 27 28 29

3 : 30 31 32 33 34 35 36 37 38 39

4 : 40 41 42 43 44 45 46 47 48 49

5 : 50 51 52 53 54 55 56 57 58 59

6 : 60 61 62 63

DSCP-CoS Mapping Table (dscp = d1d2)

d1 : d2 0 1 2 3 4 5 6 7 8 9

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

0 : 00 00 00 00 00 00 00 00 01 01

1 : 01 01 01 01 01 01 02 02 02 02

2 : 02 02 02 02 03 03 03 03 03 03

3 : 03 03 04 04 04 04 04 04 04 04

4 : 05 05 05 05 05 05 05 05 06 06

5 : 06 06 06 06 06 06 07 07 07 07

6 : 07 07 07 07

CoS-DSCP Mapping Table

CoS: 0 1 2 3 4 5 6 7

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

DSCP: 0 8 16 24 32 40 48 56

Thanks in advance,

Victor