QoS Configuration

[Steffen Frederiksen]

Hi all!

I need to match DSCP valures of EF and AF41 and make QoS queues for them, I've made the following configuration, I just wanted you guys to check it..

### QoS SDM - CISCO ####
Class-map voice
match ip dscp EF
exit
class-map video
match ip dscp AF41
exit

policy-map policy1
class voice
priority percent 10
class video
priority percent 10
class class-default
fair-queue

##### config-if ####
service-policy output policy1

Will that work??

Best Regards, Steffen.

[spremkumar]

Hi Steffen

I would go with bandwidth command under class class-default as well. I hope you are reserving only 75% of the available bandwidth in that case you may have to put bandwidth 55% since you have allocated 20% to other classess.

If you want to have more granular QoS class definition you may have to choose 11 point class model based on your requirement so that you do justice for all the traffic pattern available in your network.

regds

[Steffen Frederiksen]

I've now made an markingpolicy and a LLQ queue policy. Here Is the Output from the LLQ policy:

Service-policy output: LLQ

    Class-map: VoIP (match-any)
      510 packets, 280593 bytes
      5 minute offered rate 8000 bps, drop rate 0 bps
      Match: access-group 101
        396 packets, 274323 bytes
        5 minute rate 8000 bps
      Match:  dscp ef (46)
        114 packets, 6270 bytes
        5 minute rate 0 bps
      Queueing
        Strict Priority
        Output Queue: Conversation 264
        Bandwidth 10 (%)
        Bandwidth 10000 (kbps) Burst 250000 (Bytes)
        (pkts matched/bytes matched) 0/0
        (total drops/bytes drops) 0/0

    Class-map: class-default (match-any)
      154920 packets, 42145404 bytes
      5 minute offered rate 786000 bps, drop rate 0 bps
      Match: any
      Queueing
        Output Queue: Conversation 265
        Bandwidth 50 (%)
        Bandwidth 50000 (kbps)Max Threshold 64 (packets)
        (pkts matched/bytes matched) 457/77091
        (depth/total drops/no-buffer drops) 0/0/0

I do not understand why packets are matched in the VoIP class

(   Match: access-group 101
        396 packets, 274323 bytes
        5 minute rate 8000 bps
      Match:  dscp ef (46)
        114 packets, 6270 bytes
        5 minute rate 0 bps
)

But no packets are going into thequeue:

(

  (pkts matched/bytes matched) 0/0
        (total drops/bytes drops) 0/0

)

How can there be a match whitout any packets going to the LLQ queue??

Regards, Steffen.

[spremkumar]

Hi

Can you post your configuration here?

regds

[Steffen Frederiksen]

Extended IP access list 101
    10 permit udp any any range 50000 50050 (49650 matches)
Extended IP access list 102
    10 permit udp any any range 51000 51050 (23 matches)
Extended IP access list 103
    10 permit tcp any any range 52000 52010 (529 matches)

KOL-1812#sh class-map
Class Map match-any AppShare (id 3)
   Match access-group  103
   Match   dscp af31 (26)

Class Map match-any VoIP (id 1)
   Match access-group  101
   Match   dscp ef (46)

Class Map match-any class-default (id 0)
   Match any

Class Map match-any Video (id 2)
   Match access-group  102
   Match   dscp af41 (34)

KOL-1812#sh policy-map
  Policy Map LLQ
    Class VoIP
      Strict Priority
      Bandwidth 10 (%)
    Class Video
      Strict Priority
      Bandwidth 10 (%)
    Class AppShare
      Strict Priority
      Bandwidth 5 (%)
    Class class-default
      Bandwidth 50 (%) Max Threshold 64 (packets)

Policy Map markingpolicy
    Class VoIP
      set dscp ef
    Class Video
      set dscp af41
    Class AppShare
      set dscp af31
    Class class-default

interface FastEthernet0
description Kolding WAN
service-policy output LLQ

interface FastEthernet1
description Kolding LAN
service-policy input markingpolicy

KOL-1812#sh policy-map interface fastEthernet 1
FastEthernet1

  Service-policy input: markingpolicy

    Class-map: VoIP (match-any)
      47567 packets, 9126266 bytes
      5 minute offered rate 1000 bps, drop rate 0 bps
      Match: access-group 101
        47504 packets, 9122486 bytes
        5 minute rate 1000 bps
      Match:  dscp ef (46)
        63 packets, 3780 bytes
        5 minute rate 0 bps
      QoS Set
        dscp ef
          Packets marked 47567

    Class-map: Video (match-any)
      23 packets, 4324 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: access-group 102
        0 packets, 0 bytes
        5 minute rate 0 bps
      Match:  dscp af41 (34)
        0 packets, 0 bytes
        5 minute rate 0 bps
      QoS Set
        dscp af41
          Packets marked 23

    Class-map: AppShare (match-any)
      529 packets, 40343 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: access-group 103
        0 packets, 0 bytes
        5 minute rate 0 bps
      Match:  dscp af31 (26)
        0 packets, 0 bytes
        5 minute rate 0 bps
      QoS Set
        dscp af31
          Packets marked 529

    Class-map: class-default (match-any)
      10536310 packets, 7100592447 bytes
      5 minute offered rate 1388000 bps, drop rate 0 bps
      Match: any

KOL-1812#sh policy-map interface fastEthernet 0
FastEthernet0

  Service-policy output: LLQ

    Class-map: VoIP (match-any)
      3669 packets, 787226 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: access-group 101
        3604 packets, 783651 bytes
        5 minute rate 0 bps
      Match:  dscp ef (46)
        65 packets, 3575 bytes
        5 minute rate 0 bps
      Queueing
        Strict Priority
        Output Queue: Conversation 264
        Bandwidth 10 (%)
        Bandwidth 10000 (kbps) Burst 250000 (Bytes)
        (pkts matched/bytes matched) 1/152
        (total drops/bytes drops) 0/0

    Class-map: Video (match-any)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: access-group 102
        0 packets, 0 bytes
        5 minute rate 0 bps
      Match:  dscp af41 (34)
        0 packets, 0 bytes
        5 minute rate 0 bps
      Queueing
        Strict Priority
        Output Queue: Conversation 264
        Bandwidth 10 (%)
        Bandwidth 10000 (kbps) Burst 250000 (Bytes)
        (pkts matched/bytes matched) 0/0
        (total drops/bytes drops) 0/0

    Class-map: AppShare (match-any)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: access-group 103
        0 packets, 0 bytes
        5 minute rate 0 bps
      Match:  dscp af31 (26)
        0 packets, 0 bytes
        5 minute rate 0 bps
      Queueing
        Strict Priority
        Output Queue: Conversation 264
        Bandwidth 5 (%)
        Bandwidth 5000 (kbps) Burst 125000 (Bytes)
        (pkts matched/bytes matched) 0/0
        (total drops/bytes drops) 0/0

    Class-map: class-default (match-any)
      148723 packets, 69633897 bytes
      5 minute offered rate 1121000 bps, drop rate 0 bps
      Match: any
      Queueing
        Output Queue: Conversation 265
        Bandwidth 50 (%)
        Bandwidth 50000 (kbps)Max Threshold 64 (packets)
        (pkts matched/bytes matched) 968/127527
        (depth/total drops/no-buffer drops) 0/0/0
KOL-1812#

As said before the packets are matched in the LLQ policy, but no packets are going into the queue.

But yesterday I tried to generate more traffic, and it seems when the traffic load was high the packets where matched AND where putted into the queue. Can It be right that the packets only are putted into the queue, when there is a lot of traffic on the link?

Regards, Steffen.

[Steffen Frederiksen]

Will you please confirm that the above configuration will work?

Best Regards,

Steffen.

[cadet alain]

Hi,

Can It be right that the packets only are putted into the queue, when there is a lot of traffic on the link?

QoS congestion management techniques like LLQ, CBWFQ( priority or bandwidth commands) always come into play only when there is congestion.

So if there is no congestion then nothing in the software queues, that is normal behavior.

Regards.

Alain.

[Steffen Frederiksen]

Thanks for your reply.

And if my linies be congested, will the above configuration then still work?

I'm not sure about when to use output or input when applying a policy-map to an Interface.

[Tomas Fidler · Accepted solution]

Yes, if there will be congestion, this will work. But no sure about if you want it :).

When congestion take place ( hardware queue of physical interface is full), so on Fastethernet when there is more then 100Mbps going to that link.

When congested, Qos will look like this:

Max 25% of aviable bandwidth will be size of priority queue, that will be shared by Voice, Video and ShareApp.

Voice and video will have 10mbps on that link, and ShareAPP will have %mbps.

Min 50% of a link will be aviable for all other traffic.

Input is for marking and policing. Output is for Shaping, policing, marking ...

[Steffen Frederiksen]

and if i set the bandwidth command on the interface to for example 10mbps, it will be congested when reaching this bandwidth?

[Tomas Fidler]

No. bandwidth parametr of an inferface is only "information", doesn't limit traffic.

POLICING is what you are looking for.
Here is an explanation with an example:

http://www.cisco.com/en/US/tech/tk543/tk545/technologies_tech_note09186a00800a3a25.shtml

[Steffen Frederiksen]

Hmm, But i don't want to limit the bandwidth to my users, I only want to prioritizing my VoIP, Video, and AppShare data.

So if someone is loading a file from our file server from a remote office, his bandwidth will be limited if someone i making a VoIP call. But if there is no VoIP call he should have full bandwidth.

then its shaping right?

[cadet alain]

Hi,

So if someone is loading a file from our file server from a remote  office, his bandwidth will be limited if someone i making a VoIP call.  But if there is no VoIP call he should have full bandwidth.

then its shaping right?

No Shaping is like policing but instead of dropping packets it buffers them to transmit later this used as oversubscription prevention not to limit

user traffic.

if you use LLQ then the traffic with priority command will always get the bandwidth you set and not more, the traffic with the bandwidth command will get the  minimum bandwith you set but if other class is not using traffic then it can take bandwidth from it.

But then again I repeat all this is in times of congestion and it must be applied output as it is congestion management.

Regards.

Alain.

[Tomas Fidler]

cadetalian has right.

If you have a problem with congestion on fastethernet interface (time to time more then 100mbps need to be send), then shaping is what you need.

If 100mbps fastethernet interface is not congested and you recognize problems with VoIP quality, then shaping is not enought.

[Steffen Frederiksen]

OK. Then LLQ queue must be the right choise to VoIP.

When thinking in Output and Input, is it then from "the routers middle" I should "look" from?