Solved: show command for egress queue.

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Hi,

See this link
Catalyst 3750 Switch Software Configuration Guide, 12.2(50)SE - Configuring QoS [Cisco Catalyst 3750 Series Switches] - Cisco Systems

table 36-11 shows the Default DSCP Output Queue Threshold Map.

Is there a command which shows this on a 3560? I can't seem to find any commands which show which DSCP values are matched to which output queue.

Also the document above is for 3750s. Anyone know if the default values in the table apply to 3560s? I would think they would be the same.

Thanks.

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LucaSalvatore wrote:

but from what i can see that commnd will not show me what queue something marked with DSCP 11 (for example) will use.

Luca

Yes it will or more specifically the output queue threshold maps tell you exactly that. See this link for full explanantion -

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_46_se/command/reference/cli2.html#wp1947541

Jon

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6 Replies 6

Hi,

See this link

Catalyst 3750 Switch Software Configuration Guide, 12.2(50)SE - Configuring QoS [Cisco Catalyst 3750 Series Switches] - Cisco Systems

table 36-11 shows the Default DSCP Output Queue Threshold Map.

Is there a command which shows this on a 3560? I can't seem to find any commands which show which DSCP values are matched to which output queue.

Also the document above is for 3750s. Anyone know if the default values in the table apply to 3560s? I would think they would be the same.

Thanks.

Hi,

The Cisco Catalyst 3560 supports four egress queues per port, allowing the network administrator to be more discriminating and specific in assigning priorities for the various applications on the LAN. At egress, the switch performs scheduling and congestion control. Scheduling is an algorithm or process that determines the order in which the queues are processed. The Cisco Catalyst 3560 Series Switch supports shaped round robin (SRR) and strict priority queuing. The SRR algorithm helps ensure differential prioritization.

There are 4 egress queues are configure with 25% bandwith each. and they are in shared mode, which means that they have a minimum of 25% but can also use more from the other queues if available.

Check out the below link about default valaue in 3560 and commands to check the same

http://www.cisco.com/en/US/docs/switches/lan/catalyst3560/software/release/12.2_25_see/configuration/guide/swqos.html

http://www.cisco.com/en/US/docs/switches/lan/catalyst3560/software/release/12.2_25_see/command/reference/cli3.html

Hope to Help !!

Ganesh.H

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Thanks for the reply.

I understand the theory, my question was how to display what dscp or cos values are mapped to a output queue (the priority queue in this case)

On the link i provided there is the following table;

Table 36-11 Default DSCP Output Queue Threshold Map
DSCP Value	Queue ID-Threshold ID
0-15	2-1
16-31	3-1
32-39	4-1
40-47	1-1
48-63	4-1

All i want to know is, if there is a show command on a switch that shows the same information as what is in the table.

Hello Luca,

the following can be a starting point to see all the mappings on the switch

sh mls qos maps
   Policed-dscp map:
     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 map:
     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 map:
        cos:   0 1 2 3 4 5 6 7
     --------------------------------
       dscp:   0 8 16 26 32 46 48 56

   IpPrecedence-dscp map:
     ipprec:   0 1 2 3 4 5 6 7
     --------------------------------
       dscp:   0 8 16 24 32 40 48 56

   Dscp-outputq-threshold map:
     d1 :d2    0     1     2     3     4     5     6     7     8     9
     ------------------------------------------------------------
      0 :    04-03 04-03 04-03 04-03 04-03 04-03 04-03 04-03 04-01 04-02
      1 :    04-02 04-02 04-02 04-02 04-02 04-02 03-03 03-03 03-03 03-03
      2 :    03-03 03-03 03-03 03-03 02-03 02-03 02-03 02-03 02-03 02-03
      3 :    02-03 02-03 03-03 03-03 03-03 03-03 03-03 03-03 03-03 03-03
      4 :    01-03 01-03 01-03 01-03 01-03 01-03 01-03 01-03 02-03 02-03
      5 :    02-03 02-03 02-03 02-03 02-03 02-03 02-03 02-03 02-03 02-03
      6 :    02-03 02-03 02-03 02-03

   Dscp-inputq-threshold map:
     d1 :d2    0     1     2     3     4     5     6     7     8     9
     ------------------------------------------------------------
      0 :    01-03 01-03 01-03 01-03 01-03 01-03 01-03 01-03 01-01 01-02
      1 :    01-02 01-02 01-02 01-02 01-02 01-02 02-01 02-01 02-01 02-01
      2 :    02-01 02-01 02-01 02-01 02-03 02-03 02-03 02-03 02-03 02-03
      3 :    02-03 02-03 01-03 02-02 02-02 02-02 02-02 02-02 02-02 02-02
      4 :    02-03 02-03 02-03 02-03 02-03 02-03 02-03 02-03 02-02 02-02
      5 :    02-02 02-02 02-02 02-02 02-02 02-02 02-02 02-02 02-02 02-02
      6 :    02-02 02-02 02-02 02-02

   Cos-outputq-threshold map:
              cos: 0   1   2   3   4   5   6   7
              ------------------------------------
queue-threshold: 4-3 4-2 3-3 2-3 3-3 1-3 2-3 2-3

   Cos-inputq-threshold map:
              cos: 0   1   2   3   4   5   6   7
              ------------------------------------
queue-threshold: 1-3 1-2 2-1 2-3 2-2 2-3 2-2 2-2

   Dscp-dscp mutation map:
   Default DSCP Mutation Map:
     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

input DSCP is mapped to an internal DSCP tag.

Internal DSCP tag is mapped to CoS and CoS are mapped to queues

Hope to help

Giuseppe

but from what i can see that commnd will not show me what queue something marked with DSCP 11 (for example) will use.

LucaSalvatore wrote:

but from what i can see that commnd will not show me what queue something marked with DSCP 11 (for example) will use.

Luca

Yes it will or more specifically the output queue threshold maps tell you exactly that. See this link for full explanantion -

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_46_se/command/reference/cli2.html#wp1947541

Jon

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ah ok i understand now

thanks!

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