Preserve ToS value in DMVPN over MPLS transport

[NAGISWAREN2]

Hello all.

We designing hybrid WAN network (MPLS + Internet) for one of our client. My question is simple. Does the ToS value preserved after packet get encapsulated in GRE over IPSec(DMVPN) when sent to provider network ? This because, our MPLS provider do provides 4 class of service. And we want to utilize QOS service within Provider network as well , so that it becomes end-to-end QOS. 

Nagis

[Peter Paluch · Accepted solution]

Hello Nagis,

I believe you will need to ask your Service Provider whether the DSCP markings of IP packets traversing its network will be transparently carried across.

To my best knowledge, when a router adds a new IP header as a result of encapsulating a packet (IP into GRE, GRE into IPsec), it will copy the inner DSCP value to the outer DSCP value. Therefore, as far as tunneling is concerned, the DSCP value should be preserved. The handling of the DSCP values in your provider's core is a question that only your SP can fully answer.

Best regards,
Peter

[Joseph W. Doherty]

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Posting

As Peter describes, Cisco equipment has, for some time, copies original packet's ToS to the encapsulated header's ToS.

What you might run into, your ToS might need mapping into your provider's ToS.  I don't recall whether that can be done on the device that does the encapsulation.