QoS Question

[Brian Green]

I'm not sure if this can be done without a bunch of manual configuration.

I have a router (an ISR 2921 running 15.4(3)M3) that is connected to other ISR routers (2921s running 15.4(3)M3 and 4451-Xs running 15.4(3)S3) using DMVPNs.  The DMVPN tunnels could be over several different speed transports from Satellite links with bandwidth of 0.5Mbps to Internet-based links running at a much higher speed.  I'm trying to run QoS between the two routers - right now, the problem I am facing is that I can only apply one service-policy to the outbound interface - so if I have several different speed links, I'm only doing QoS traffic shaping for the slowest speed.  What I would like to do is have the QoS set to use a different policy based on the subnet - I'm thinking I would need to have one policy-map with a whole bunch of match access-group statements in it, and matching ACLs based on the subnet of each device.  Just to further complicate this, there are several tunnels on the inside of the router.

Thanks in advance for any ideas!

Quick drawing:

[Joseph W. Doherty]

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Posting

Later versions of DMVPN, support per logical device QoS policies.  The remote requests the policy for the DMVPN hub to use to it.  These policies can have different shaper limits.

[Brian Green]

That would be using the ip nhrp group statement on the Spoke side of the tunnel, correct?  And would that apply to all traffic traversing the tunnel, regardless of the direction?

[Joseph W. Doherty · Accepted solution]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

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In no event shall Author be liable for any damages wha2tsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

I don't recall the actual command, although likely it's one of the NHRP commands.

No, the policy only applies to traffic on the hub going to one specific spoke.

For spoke to hub traffic, you can QoS manage "normally".

BTW, in one the later IOS versions, DMVPN also supports dynamic shaping (i.e. it reacts to end-to-end congestion), which might work in both directions.

[Brian Green]

Thanks!  That's what I thought - I'm now looking to establish a common DMVPN from Spoke to Hub that I can set the QoS policies on.  I'll set them on the spoke directly, but have the spokes use the nhrp group to set the policy on the tunnel from the hub.  That way, the user has to configure the Spoke when they get it - and as long as they use a group that's known then there is no additional configuration needed per spoke on the hub - we can do it once for every possible config.