Unanswered Question
Nov 17th, 2008


Can I don policy based routing using qos-group?

If I mark a packet with qos-group 1 and that packet goes to the other end directly connected router, will that router also see this packet with qos-group 1 or not?

Any supporting URLs will help.



I have this problem too.
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Giuseppe Larosa Mon, 11/17/2008 - 05:42

Hello Sourabh,

>> If I mark a packet with qos-group 1 and that packet goes to the other end directly connected router, will that router also see this packet with qos-group 1 or not?

No, qos-group is an internal tag in a node and it is not exported in the outgoing packet.

There are some scenarios when you mark the qos-group at an ingress interface and then on the outgoing interface you have a policy-map outbound that performs some actions on traffic classes defined on the qos-group basis.


The QoS group value is local to the router, meaning that the QoS group value that is marked on a packet does not leave the router when the packet leaves the router. If you need a marking that resides in the packet, use IP precedence setting, IP differentiated services code point (DSCP) setting, or another method of packet marking.


Hope to help


souagarw Mon, 11/17/2008 - 07:04

Thanks Giuseppe for the explanation.

I'm looking to deploy QoS for DMVPN network at the hub site and is referring to the Cisco DMVPN design document has a sample how to do it.

My question is that in the sample, the criterion for classify traffic into different spoke site is based on static pre-configured prefixes. But I would like it to be route based. Is there a way to do it? Please look at the QoS section at the document below.




Giuseppe Larosa Mon, 11/17/2008 - 09:54

Hello Sourabh,

the key command for QoS in DMVPN is the

qos pre-classify

On the headend hub router, the mGRE tunnel interface is configured for qos pre-classify because the service policy is matching on the destination IP address in the original unencrypted IP header. The service policy, however, is applied to the outside interface, and the packets are encrypted when the QoS matching decision is invoked. Configuring qos pre-classify gives the service policy the ability to match on the clear text values.


interface Tunnel0


qos pre-classify


interface FastEthernet0/1.100

description Outside interface

This is from page 49 of the document in your link.

Normally, a DiffServ Model is used with some traffic classes based on the DSCP field with some well-known settings like EF for VoIP bearer channels (conversations)

I see that there is also an example based on destination address with ip access-lists. This can be helpful if your address plan allows to identify some services with some type of destinations

This directly maps to the routing table in a static way.

However, the scheduler you can use is elastic resources not used are redistributed between the other traffic classes.

So we can say there is not a strict need to be able to map to the routes in a "dynamic way".

If you look at the QoS command reference we can see that among the many parameters/options of the match commands there are no attribute of dynamic routes.

One could think to match a route tag or other route property but all the commands for setting and for matching a route tag are available only in route-maps and not within class-map objects.

So as far as I know QoS objects are oriented to traffic flows and you have a choice between using in-band markings like DSCP in DiffServ model or you can classify the flows based on the destination address but referencing them directly with ACLs

Hope to help


aghufran Thu, 07/24/2014 - 11:21

Hi Giuseppe,

I am trying to do exactly that - mark qos-group on the incoming and use that on the outgoing on the same router. The problem I am facing is that the outgoing policy does not seem to be picking up the qos-group internal markings. When I view the output of the outgoing policy, I do not see any hits against the policies which are using qos-groups. I am using a ME3800X to do this.

Have been going though the soft conf guide but cannot seem to figure out why this is not behaving as detailed in the guide.

I wanted to find out if you have experience of using qos-group and came across such a situation.


Abid Ghufran.


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