Subject: [nvo3] Comments on draft-ietf-nvo3-overlay-problem-statement

From: Eric Gray <[email-masked]>
Date: Thu, 14 Mar 2013 11:20:48 -0400

Had to forward this as the commenter used an invalid email address. 

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> Subject: Your comment on draft-ietf-nvo3-overlay-problem-statement-02
> From: Eric Gray <[email-masked]>
> Message-Id: <[email-masked]>
> Date: Wed, 13 Mar 2013 17:10:59 -0400
> To: "[email-masked]" <[email-masked]>
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> Qin,
> 
> In reading your comment, it seems that you're both asking what we
> mean by the text and answering the question with your next question.
> 
> The text you ask about is identifying the case where more than one
> router connects a virtual network to an otherwise separate virtual
> network.  The optimal forwarding concern is that it is difficult for a
> virtual host or server located within the first virtual network to know
> which of the multiple routers connecting the two virtual networks is
> the optimal choice for connecting to a host or server in the second
> virtual network.
> 
> This is a concern when there are possibly multiple local forwarding
> devices between the first host/server and any of the potential routers
> that connect the two virtual networks and/or a similar situation exists 
> in the second virtual network between any of these candidate routers
> and the second host/server.  How is the host supposed to determine
> which of the multiple routers in this case provides the optimal path.
> 
> This is pretty much the case you identify when you ask how we are
> "going to deal with the optimal forwarding between two VMs [that]
> belong to different subnet[s]."
> 
> It seems that we're at least talking about the same thing.  Can you
> make a specific text proposal that would make our text clearer?
> 
> --
> Eric
> 
> You wrote:
> I reviewed the change in section 3.7 "optimal forwarding"of NVO3 problem statement.
> It said:
> "
>   IP implementations in network endpoints typically do not distinguish
>   between multiple routers on the same subnet - there may only be a
>   single default gateway in use, and any use of multiple routers
>   usually considers all of them to be one-hop away. 
> "
> It seems you talk about one tenant system is multihomed to multiple NVEs in the same subnet.
> I am not sure how much of this is related to optimal forwarding?
> Are you assuming only one NVE is active? or all the NVEs placed in the same subnet are active?
> or some of NVE placed in the same subnet are active to a set of VMs while the other