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6500 mls qos

paul amaral
Level 4
Level 4

Hi, hoping someone can help.

according to the cisco documentation 1p1q0t RX queues default to cos 5 mapped to the priority queue 2 threshold 1.

Receive queues [type = 1p1q0t]:

Queue Id Scheduling Num of thresholds

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

1 Standard 0

2 Priority 1

queue-limit ratios: 80[queue 1] 20[queue 2]

queue thresh cos-map

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

1 1 0 1 2 3 4 6 7

2 1 5

Packets dropped on Transmit:

BPDU packets: 0

queue thresh dropped [cos-map]

however when i enabled mls qos im not seeing this, note that there is nothing mapped to priority queue 2. Do i have to manually set this, if so how is it done.

Queueing Mode In Rx direction: mode-cos
Receive queues [type = 1p1q0t]:
Queue Id    Scheduling  Num of thresholds
-----------------------------------------
    1         Standard            0
    2         Priority            1

queue-limit ratios:    100[queue 1]   0[queue 2]

queue thresh cos-map
---------------------------------------
1     1      0 1 2 3 4 5 6 7
2     1

my hardware.

Mod Ports Card Type                              Model              Serial No.
--- ----- -------------------------------------- ------------------ -----------
  1   48  SFM-capable 48-port 10/100 Mbps RJ45   WS-X6548-RJ-45     SAL0751QS8S
  2   48  SFM-capable 48-port 10/100 Mbps RJ45   WS-X6548-RJ-45     SAL0749Q6TF
  5    2  Supervisor Engine 720 (Active)         WS-SUP720-3BXL     SAL09158YJ2
  6    2  Supervisor Engine 720 (Hot)            WS-SUP720-3BXL     SAL1028UPGH

8 Replies 8

Siddharth Chandrachud
Cisco Employee
Cisco Employee

Simply enabling mls qos will not accomplish your task.

To enable priority queuing, 3 things need to be done:

Assuming, lets say you want make sure voice packets go to priority queue, then following configuration can be taken as an example.

There are multiple ways to accomplish this, I am providing one example.

There are other auto-qos functionalities also that you can explore.

1. Instructing the switch to trust the DHCP markings on the incoming packets.

Switch(config-if)# mls qos trust dscp

2. 6500 uses COS values to map packets into appropriate queues.

There is a default DSCP to COS map that is configurable.

http://tools.cisco.com/squish/D3F0F

Switch(config)# mls qos map dscp-cos 46 40 to 5    (46 for DSCP EF , 40 for signaling)

3. Map Cos 5 to the strict priority queue.

Switch(config)# interface gigabitethernet 1/1
Switch(config-if)# priority-queue cos-map 2  5   ( queue 1 cos value 5 )

Verification:

Issue command: show queueing int gig 1/1

Qos reference guide:

http://tools.cisco.com/squish/A6c47


You can test this out and see if it helps.

Sid Chandrachud

Cisco TAC

i think your giving me a solution for the outgoing queue. the problem is on the incoming queue, 1P1Q0T. when i do a show queueing the receive queue is not showing cos 5 mapped to the receive queue 2. I also dont have the option to map cos 5 to incoming queue 2 and i read someone on cisco's site that cos 5 should be mapped to receive queue 2. btw i do have everything else working and setup.

core.frv.ma(config-if)#rcv-queue cos-map ?
  <1-1>  enter cos-map queue id

can't put 2

Queueing Mode In Rx direction: mode-cos
Receive queues [type = 1p1q0t]:
Queue Id    Scheduling  Num of thresholds
-----------------------------------------
   1         Standard            0
   2         Priority            1

queue-limit ratios:    100[queue 1]   0[queue 2]

queue thresh cos-map
---------------------------------------
1     1      0 1 2 3 4 5 6 7
2     1

Ok, understood.

To map CoS values to the receive and transmit strict-priority queues:
http://tools.cisco.com/squish/2965e

6500(config)# interface gigabitethernet 1/1
6500(config-if)# priority-queue cos-map 1 7

Again, you might only see option as 1.
When mapping CoS values to the strict-priority queues,

the queue 'number' in the configuration is always 1.
(It does not mean its applied to queue 1 )

Do the configuration and paste the complete output of:
show queueing interface <>

Sid Chandrachud

SId,

the problem is on the RX queue, as you will see from the command below the TX cos maps are corrected. The RX queue as all COS value mapped to queue 1 instead of having cos 5 mapped to RX priority queue which is the default from the cisco documentation i read but my output doesnt show this.

I read on the forum that it might be realted to the fact the that interface is not a trunk and not seeing COS thus not mapping COS 5 to the priority queue on the incoming. Also issuing the command you listed below does not do anything for the RX queue. Again its odd that the RX queue is not showing what cisco says is the default, cos 5 mapped to rx queue 2. (see below for example)

here is the interface

interface FastEthernet1/15
bandwidth 44736
ip address xxx
no ip route-cache
load-interval 30
mls qos trust dscp
hold-queue 100 in

here is what i have:

Interface FastEthernet1/15 queueing strategy:  Weighted Round-Robin
  Port QoS is enabled
  Trust state: trust DSCP
  Extend trust state: not trusted [COS = 0]
  Default COS is 0
    Queueing Mode In Tx direction: mode-cos
    Transmit queues [type = 1p3q1t]:
    Queue Id    Scheduling  Num of thresholds
    -----------------------------------------
       1         WRR                 1
       2         WRR                 1
       3         WRR                 1
       4         Priority            1

    WRR bandwidth ratios:  100[queue 1] 150[queue 2] 200[queue 3]

    queue random-detect-min-thresholds
    ----------------------------------
      1    70[1]
      2    70[1]
      3    70[1]

    queue random-detect-max-thresholds
    ----------------------------------
      1    100[1]
      2    100[1]
      3    100[1]

    WRED disabled queues:

    queue thresh cos-map
    ---------------------------------------
    1     1      0 1
    2     1      2 3 4
    3     1      6 7
    4     1      5

    Queueing Mode In Rx direction: mode-cos
    Receive queues [type = 1p1q0t]:
    Queue Id    Scheduling  Num of thresholds
    -----------------------------------------
       1         Standard            0
       2         Priority            1

    queue-limit ratios:    100[queue 1]   0[queue 2]

    queue thresh cos-map
    ---------------------------------------
    1     1      0 1 2 3 4 5 6 7
    2     1


  Packets dropped on Transmit:
    BPDU packets:  0

    queue thresh    dropped  [cos-map]
    ---------------------------------------------------
    1     1                       0  [0 1 ]
    2     1                       0  [2 3 4 ]
    3     1                       0  [6 7 ]
    4     1                       0  [5 ]

  Packets dropped on Receive:
    BPDU packets:  0

    queue thresh             dropped  [cos-map]
    ---------------------------------------------------
    1     1                       0  [0 1 2 3 4 5 6 7 ]

what should be the default RX:

Receive queues [type = 1p1q0t]:

Queue Id Scheduling Num of thresholds

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

1 Standard 0

2 Priority 1

queue-limit ratios: 80[queue 1] 20[queue 2]

queue thresh cos-map

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

1 1 0 1 2 3 4 6 7

2 1 5

Packets dropped on Transmit:

BPDU packets: 0

queue thresh dropped [cos-map]

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

1 1 0 [0 1 ]

2 1 0 [2 3 4 ]

3 1 0 [6 7 ]

4 1 0 [5 ]

Packets dropped on Receive:

BPDU packets: 0

queue thresh dropped [cos-map]

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

1 1 0 [0 1 2 3 4 6 7 ]

2 1 0 [5 ]

Hi Paul,

Try rcv-queue cos-map 2 0 5

I don't have a card with 1p1q0t to test on, but I think it may be something like that.

Check out the release notes for CSCsg68522.  I think that if you have all ports on that port-asic trusting or not trusting, the cos-map may look as you expect.  When its mixed you need to configure it yourself.

Chad

chad the problem is that the lan card i'm using only supports incoming COS mode. Since im trusting DSCP and not COS on some ports, and all ports 1-48 are on the same ASIC it will not map cos 5 to the incoming priority queue. if i was trust all cos it would work per default, mapping cos 5 to incoming incoming priority queue 2.

Hi Paul,

Have you tried configure ingress queue based on DSCP? Check section 'Configuring Ingress DSCP-Based Queue Mapping' on the fololwing link:

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/qos.html

HTH,

Lei Tian

i was just about to update this.

here is what i did that worked, the fast-ethernet card im using only supports cos-mode "Queueing Mode In Rx direction: mode-cos" because all 48 ports on that card use the same ASIC if you configure some ports to trust DSCP and other to trust COS the default incoming queue mappings will not take place, so cos 5 will not be mapped to incoming priority queue 2. What needs to happen is you need to trust COS on all the ports and then use a policy map to trust DSCP on some ports instead of trusting DSCP on the port itself. This is what worked for me, thanks to  Peter Rathlev from the cisco-nsp list.

Policy Map trust-dscp
   Class any-traffic-class
     trust dscp

interface FastEthernet1/15

mls qos trust cos
service-policy input trust-dscp
hold-queue 100 in

Queueing Mode In Rx direction: mode-cos
Receive queues [type = 1p1q0t]:
Queue Id    Scheduling  Num of thresholds
-----------------------------------------
   1         Standard            0
   2         Priority            1

queue-limit ratios:     80[queue 1]  20[queue 2]

queue thresh cos-map
---------------------------------------
1     1      0 1 2 3 4 6 7
2     1      5

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