Re: IPoIB link address

>Hi,
>
>In the IP encapsulation draft , section 6.1.2, it is indicated that the 
>Q_Key used should be that of the
>broadcast-GID. Which broadcast GID should be used? Specifically, if the
>IPv4 and IPv6 broadcast GIDs are assigned different Q_keys, which Q_Key
>should be used?

You should look at the link & multicast draft, not the encapsulation
draft for the Q_Key assignment. In that draft Q_Key is described as an
IPoIB link attribute shared by both IPv4 and IPv6. (See section 6.2 IPoIB
Link Q_Key.)

>
>The issue with potentially allowing different Q_Key values for the 2 GIDs 
>is that 2 separate QPs will have to
>be allocated for IPv4 and IPv6 traffic respectively and will require the 
>IPoIB driver to keep track of upper layer protocols.
>If everyone agrees that this is a problem, there are 2 ways to address the 
>issue:
>1) Require the 2 broadcast GIDs to have the same attributes such as Q_key, 
>MTU etc.

See above. Q_Key and MTU are considered "link" attributes. By definition,
IPv4 and IPv6 running on top of the same link must use the same set of
"link" attributes. If this is not clear from the current drafts we can
certainly fix it. (Well Vivek and I are working on combining the two drafts
into one. One benefit of the merge is to remove any possible inconsistency.)

Thanks for pointing this out,

Jerry (speaking obviously as a co-author not a co-chair)

>or
>2) Create a single broadcast GID to define the link.
>
>-Vandana
>  
>
>
>_______________________________________________
>IPoverIB mailing list
>[email protected]
>https://www1.ietf.org/mailman/listinfo/ipoverib