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QOS in the midle of the GRE tunnel

p.diaz
Level 1
Level 1

Hi. Its possible to any router in the midle of a GRE tunnel to recognize the DSCP values and prioritize according with that values?

8 Replies 8

Collin Clark
VIP Alumni
VIP Alumni

You would have to tag the GRE packet since it encapsulates the IP packet. That could be fun to lab up. Figure out how to recognize the DSCP value, then encapsulate in GRE and then apply the original DSCP value in the GRE packet.

ok. The IP packet comes marked with a DSCP value into the net. And I like to know if the GRE header inherit the DSCP value from the IP header. Whit that heritage we can manage the packets according with the DSPC field.

You will have to mark the GRE packet.

Hi,

You are correct, the ToS field of the inner header is copy into the outer IP header.

http://www.cisco.com/en/US/docs/ios/11_3/feature/guide/greqos.html

HTH

Laurent.

for dscp and wfq qos pre-classify is used in gre.

regards

shivlu jain

Hi Shivlu,

qos pre-classify is used if the classification on the physical egress interface (where GRE packets are sent) is still based on inner IP addresses and L4 ports.

If your traffic is already marked (IPP or DSCP) at the ingress (before encapsulation), you don't need this feature and can directly classify your traffic at the egress based on the ToS field.

HTH

Laurent.

pre-classify feature is valid only on the head-end of the GRE tunnel.

the original question says that in between on a transit router so DSCP/IPP should be used.

Joseph W. Doherty
Hall of Fame
Hall of Fame

Yes, assuming you mean the DSCP value in the ToS of the GRE packet.

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