Re: FCIP: Comment 120

["Mallikarjun C." <cbm@rose.hp.com>]

David,

From the text that Murali posted on this thread - 

" The FC-BB-2_IP Reference Model supports one logical IP Interface and
allows sharing a 4-byte IPv4 or 16-byte IPv6 address in the following ways:

a)A single IP address per FC-BB-2_IP device
  - A single IP address shared by all FC/FCIP Entity pairs"


It's a simple extension to assume that the same well-known TCP port
*could* be used for all Pairs, which results in multiple Pairs at the same *address*
necessitating a *name* of some sort to identify the intended FSF recipient.

>Having seen no other
> participants in this discussion,

Please see Murali's message.

>I also believe that the rough
> consensus of the WG is not to change FCIP in this fashion.

I am *not* advocating a change.  I am simply concerned that the FCIP 
text is neither ruling out certain possibilities explicitly, nor defining the 
architectural hooks to cater to all possibilities.  I'd be perfectly okay with
a statement that states that each IP-TCP Address-Port belongs to exactly
one Pair (though the text then should ideally say why). 

Thanks.
--
Mallikarjun

Mallikarjun Chadalapaka
Networked Storage Architecture
Network Storage Solutions Organization
Hewlett-Packard MS 5668 
Roseville CA 95747
cbm@rose.hp.com


----- Original Message ----- 
From: <Black_David@emc.com>
To: <roweber@acm.org>; <ips@ece.cmu.edu>
Cc: <cbm@rose.hp.com>
Sent: Thursday, May 09, 2002 1:39 PM
Subject: RE: FCIP: Comment 120


> > > Besides, I don't see anything in the current document that prohibits
> multiple
> > > FC/FCIP Entity Pairs from sharing the same IP/TCP address/port - and I
> believe
> > > that is the right architectural approach.
> > 
> > In the Orange County meeting, the FCIP contributors were told that we
> > had to stop relying on knowing the exact IP Address and Port to decide
> > the end points of the FCIP Links. We were NOT told that we had to
> > allow multiple FC/FCIP Entity Pairs to share a single IP Address/Port.
> > In fact, I believe we were told that we could proceed using such
> > an assumption.
> 
> While Ralph doth protest a bit much, I believe he has the better part
> of this discussion.  It is completely reasonable to identify an IP
> service instance as "that which responds when contacting TCP port X
> at IP address a.b.c.d" - for example, there's only one http server
> behind port 80, but there might be a different one behind port 8080.
> 
> If there's a NAT involved, the discussion gets a bit subtle, but
> the principle remains - one opens a TCP connection to port X at
> IP address a.b.c.d, and expects to talk directly to a specific instance
> of an IP-based service.  I don't see any need to change FCIP to
> allow multiple FC/FCIP Entity Pairs to share a single IP Address/Port;
> the fact that multiple TCP connections to the same FC/FCIP Entity
> Pair can share that TCP Port seems sufficient.  Having seen no other
> participants in this discussion, I also believe that the rough
> consensus of the WG is not to change FCIP in this fashion.
> 
> Thanks,
> --David
> ---------------------------------------------------
> David L. Black, Senior Technologist
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