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sample QOS for video , voice , Data , ATM Traffic

Hi Guys

Kindly , Post here sample QOS for video , voice , Data , ATM Traffic , dedicated Link Bandwidth is 8 Mbps

Thanks

4 REPLIES 4
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VIP Expert

Hello,

what do you mean with ATM traffic ? Which platform is this on ?

Here is a generic policy for Voice, Video, and a default class for the rest (including data):

class-map match-any VOICE
 match dscp cs3
 match ip dscp ef
class-map match-any VIDEO
 match dscp cs4
 match dscp af41

policy-map QOS_OUT
 class VOICE
  priority percent 30
 class VIDEO
  priority percent 30
 class class-default
  fair-queue
  random-detect

interface FastEthernet4
 service-policy QOS_OUT out

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Some commentary on Georg's generic policy . . .

class-map match-any VOICE
 match dscp cs3
 match ip dscp ef
class-map match-any VIDEO
 match dscp cs4
 match dscp af41

The above classes expect DSCP tagging to correspond to the the traffic of that class type.

The VOICE class match statements have different syntax, both are effectively the same, but which is used depends on the platform and IOS version.  (One is a "newer" syntax, although I forget, off the top of my head, which is the newer.)

Match statement with tags often support up to 4 tags per statement.  Which sometimes can be handy if you want an additional "and" condition, for example:

class-map match-all VOICE
 match dscp ef cs3
 match <some other criteria, e.g. a subnet>

Also match statements are processed in sequence, which may have implications for efficiency.

Also for efficiency, if you're willing to match AF42 and AF43 as part of Video, you might:

class-map match-any VIDEO
 match ipprec 4

policy-map QOS_OUT
 class VOICE
  priority percent 30
 class VIDEO
  priority percent 30
 class class-default
  fair-queue
  random-detect

In the above, VIDEO is using LLQ.  It and VOICE use 60%.  Cisco recommends not to exceed 1/3 for LLQ.  I would recommend using care exceeding 1/3 and not to exceed 1/2.

I would also note, video comes in two major flavors, steaming/buffered video and live/real-time video.  The former shouldn't ever need LLQ.  The latter might not need it either, but if not using it, you do often need to provide priority close to LLQ.  (The reason you want to, if possible, avoid mixing VoIP and real-time video in LLQ, the usual larger packet sizes of the latter can impact VoIP's jitter.

Lastly, for class-default, if the CBWFQ supports it, declare a bandwidth percentage.  Also, I highly recommend not using WRED unless you really, really understand the technology, and especially don't use it with FQ (unless it's the FRED variant).

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@Joseph W. Doherty wrote:

 

In the above, VIDEO is using LLQ.  It and VOICE use 60%.  Cisco recommends not to exceed 1/3 for LLQ. 

video comes in two major flavors, steaming/buffered video and live/real-time video.  The former shouldn't ever need LLQ.  The latter might not need it either, but if not using it, you do often need to provide priority close to LLQ.  (The reason you want to, if possible, avoid mixing VoIP and real-time video in LLQ, the usual larger packet sizes of the latter can impact VoIP's jitter.


Could you give an example config of what would be a better approach? ie; a class map for LLQ, then (whatever is best) for voice, video, general traffic?

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VIP Expert

As Georg already asked, we would need to know the platform, as QoS features, and often syntax, vary between platforms and sometimes even IOS versions.

Also as Georg asked, please clarify the meaning of "ATM Traffic"?

If the physical interface also 8 Mbps?  If not, you would need a shaper.

What kind of video, real-time or streaming?