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Is the GRE tunnel ID carried over the network?

asked 2016-01-14 07:24:15 -0500

Dragos gravatar image

I would like to know if the tunnel ID is local to each endpoint of a tunnel or if it is carried over the network so that both endpoints know about it. If it is carried over the network, then is it placed in the GRE header (which field? Key?) or if there is an additional header for it

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answered 2016-01-14 12:22:25 -0500

dbaxps gravatar image

updated 2016-01-14 12:36:48 -0500

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Thanks, second link seems to indicate that the tunnel ID is carried in the GRE header. A search on Google lead me to an excerpt from "Learning OpenStack Networking" in Google Books. There it is written that the ID is stored in the GRE KEY field (32-bit). Does it imply tunnel_id_range 0 - 2^32?

Dragos gravatar imageDragos ( 2016-01-14 18:25:46 -0500 )edit

Take a look at For myself ( not network engineer ) Assaf Muller blog is usually sufficient. It addresses a lot of Neutron work-flow detailed explanations, in particular, clear explanation of DVR and ARP Proxy functionality ( for instance ).

dbaxps gravatar imagedbaxps ( 2016-01-15 00:34:21 -0500 )edit

Yes, those blogs are very good in illustrating how various OpenStack components interact. But, I work with network research and sometimes it is necessary that I understand low-level details about network traffic. Thanks for links!

Dragos gravatar imageDragos ( 2016-01-15 01:39:41 -0500 )edit

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Asked: 2016-01-14 07:24:15 -0500

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Last updated: Jan 14 '16