Qos / Class of Service / Traffic

[MisterTof]

Hello,

How to determine that a type of traffic should be assigned to a particular class of service? Are there any rules on the subject?

Voice

Realtime interactice

Multimedia conferencing

Broadcast Video

Multimedia streaming

Signaling

Network Control

Network management

Transactionnal data

Bulk data

Best effort

scavenger

Thank you. Christophe.

[Georg Pauwen]

Hello,

not sure what you are asking. Auto QoS creates classes, otherwise you are free to create any class and assign any sort of traffic. Are are you looking for the specific traffic for the classes you mentioned ?

[MisterTof]

Hello Georg,

I want to create my own classes. and although I am free to assign traffic to a given class, certain types of traffic must, in my opinion, go into very specific classes. True or false? for example :

Voice traffic should be in voice classe

network management trafic should be in network management classe

http trafic should be in bulk data class

and so on

I mean what is scavenger traffic? what is bulk traffic ?

if I look at all the traffic that passes through the network (e. g. with nbar) how can I decide which type of traffic should be associated with which class?

Christophe.

[MisterTof]

Hello,

For example :

http://www.ciscopress.com/articles/article.asp?p=357102&seqNum=5

"The Scavenger class is intended to provide deferential services, or less-than best-effort services, to certain applications. Applications assigned to this class have little or no contribution to the organizational objectives of the enterprise and are typically entertainment oriented in nature. These include peer-to-peer media-sharing applications (KaZaa, Morpheus, Groekster, Napster, iMesh, and so on), gaming applications (Doom, Quake, Unreal Tournament, and so on), and any entertainment video applications."

Christophe.

[Georg Pauwen]

Hello,

auto qos handles a hierarchical dscp/af/cs scheme, meaning the highest values go into the highest class. Scavenger traffic handles anything with cs1. In the end is it kind of arbitrary, and while in most situations, auto qos is probably sufficient, you might be better off creating your own policies...

[paul driver]

Hello

looks like you’ve hit the full recommended 11 class map allocation with that lot excluding the class class-default 

No rules as such but when your expecting congestion you would need to make sure your real time traffic such as voice-video services don’t incur to much latency or jitter so it’s services begin to fail - So for those you would probably want to prioritise this traffic with LLQ  And with the rest share the remainder bw between your most- least preffered traffic  

least preffered being your don’t care class ie- best effort - class class default 

However this would not include your network control - management traffic as you would not want your igp or monitoring services to be included in the don’t care class  so they would need some of their own bw allocation 

Please review this best pratice document to give you a very understanding on how to plan your qos

 https://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/WAN_and_MAN/QoS_SRND/QoS-SRND-Book/QoSIntro.html

[MisterTof]

Hello,

Not sure to understand all  what you say Georg & Paul (sorry I am French and can make mistakes in translation or undertsanding). I agree that autoqos works in most situations but autoqos only trusts cos/dscp values. Looking at http traffic (wireshark capture) i note that it is taggued dscp 0. So this kind of trafic is assigned to best-effort class and i would like to assigned it to bulk-data class.

Christophe.

[paul driver]

Hello

Just because they are default its doesn't mean it  stays that way, the beauty of qos is you can manipulate it to your liking.

Take http or https traffic, you can classify and mark this traffic to any dhcp values you like and/or prioritize/police or allocate minimum BW to it using NBAR as it exits your network

example
class-map match-any WEB
match protocol http
match protocol secure-http

policy-map child
class WEB
set ip dscp 21
bandwidth 10
class class-default
fair-queue

policy-map parent
class class-default
shape average 10240000
service-policy child

int x/x

description wan interface
service-policy output parent