[openib-general] RE: RDMA connection and address translation API

[Yaron Haviv]

> -----Original Message-----
> From: Roland Dreier [mailto:rolandd at cisco.com]
> Sent: Thursday, August 25, 2005 12:13 PM
> To: Michael S. Tsirkin
> Cc: Yaron Haviv; openib-general at openib.org
> Subject: Re: RDMA connection and address translation API
> 
>     Michael> Wouldnt it be better to use some bits in the service ID
>     Michael> field for this?
> 
> This would also be OK.  But Annex 3 of the IBA spec has already
> defined the service ID field without any reserved bits we can use.
> For example, if the first byte is 0x01, then the IETF is allowed to
> use any value they want for the rest of the service ID.  So if we want
> to keep backwards compatibility with the spec, this approach might be
> difficult.
> 

The IB ServiceID is 64 bits and TCP is 16 bits, so we can still take
some bits in the middle to define what Michael was proposing, this may
be a simpler change in IBTA than changing the CM header, but both
options are valid 

Yaron

> Anyway, what's the disadvantage of using a reserved bit or two from
> the CM REQ?
> 
>  - R.