Re: FCEncap Last Call Comment 39

[Ralph Weber <ralphoweber@compuserve.com>]

Mallikarjun,

FCIP and FC-BB-2 allow Class F frames to transit
while in the Unsynchronized state. All other
Classes of frames cannot transit while in the
Unsynchronized state.

I may get corrected by those more versed in Fibre
Channel, but I believe that Class F frames can
transit while in the Unsynchronized state because
they are exchanged only between adjacent switches.

It is certainly true that Class F frames MUST be
allowed to transit while in the Unsynchronized
stated because they are REQUIRED to setup the
Fiber Channel Time Service, which is a prerequisite
for time stamping frames.

Hope this helps.

Ralph...

"Mallikarjun C." wrote:

> Ralph,
>
> Thanks for the response.  Query below.
> --
> Mallikarjun
>
> Mallikarjun Chadalapaka
> Networked Storage Architecture
> Network Storage Solutions Organization
> Hewlett-Packard MS 5668
> Roseville CA 95747
> cbm@rose.hp.com
>
> > Comment 39 Technical
> >
> >    - I think it might be useful to add a statement in this section along
> >      the lines of - If the encapsulating protocol mandates Synchronized
> >      operation, the entity MUST NOT accept TCP connections on the well-
> >      known port(s) unless the entity is in the Synchronized state.
> >
> >    Rejected
> >
> >    Since encapsulating protocols are allowed to specify operation in
> >    the Unsynchronized state, specifying this level of detail about how
> >    Synchronized operation is handled over reaches the bounds of this
> >    specification.
>
> This is a query to FCEncap as much as it is to FCIP and iFCP.
>
> I don't claim to be well-versed with the latest FC specs, but my understanding
> is that the R_A_TOV represents a hard requirement placed on FC fabrics in terms
> of life expectancy of the FC frames.  If it is indeed so, then could you please
> explain how Unsynchronized operation with its non-deterministic frame lifetime
> in the "fabric" could be legal for any encapsulating protocol?
>
> I struggled with the same question in my reviewing of FCIP and iFCP as well,
> and would appreciate a clarification.