RE: fcovertcpip - N_Port support.

["Murali Rajagopal" <muralir@lightsand.com>]

Venkat/Josh: (With my TC hat off)

The FCIP as it is written today specifically deals with E_Ports. In other
words, the FCIP device connects to a FC Switch like any FC Switch.This
appraoch in theory could be extended to include N_Port connectivity.
Tunneling FC data frames in this case is the trivial part. The complex part
surfaces when attempting to "replace" the functions and infrastructure
provided by the Fibre Channel Network.

I am NOT in favor of mixing the two specifications for one good reason - the
goals are very different. FCIP's goal is to allow FC Switched networks to be
extended over the IP Network and therefor enhances the existing FC-based SAN
island connectivity. I beleive iFCP's goal is to bypass FC switched networks
altogether and it really does not deal with FC based SANs.

For the above reasons the FCIP specification tends to be relatively simple
compared to iFCP.

Regards,

Murali Rajagopal
LightSand Communications

-----Original Message-----
From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of
Joshua Tseng
Sent: Thursday, December 14, 2000 3:57 PM
To: Venkat Rangan; IP Storage Working Group
Subject: RE: fcovertcpip - N_Port support.


Venkat,

I believe you have a good starting point.  I will offer a
second area of consolidation--that iFCP and FCIP can adopt
a common encapsulation and framing method.  This shouldn't
be too hard--a common encapsulation over TCP that can
support both FCIP and iFCP should be easy to work out.

However, the biggest difference between iFCP and FCIP is
in the addressing and routing mechanisms.  iFCP maps FC
addresses to IP addresses, which allows IP switches and
IP routing protocols to route the encapsulated frames to the
destination FCP Portal over the IP network.  FCIP on the
other hand relies on the FC switch and FSPF routing protocol
to route traffic to the final destination, with the role of
the IP network only to connect tunnel endpoints within the
FC network.  This is the difference which I am having a hard
time reconciling.

Maybe it might be possible to create a common framework,
(rather than a common protocol), under which both of these
separate and unrelated mechanisms can be specified.  The
framework would allow for address translation of FC addresses
into IP addresses & N_PORT ID's, as well as for tunneling of
the frames unchanged over the IP network.

How does this suit everyone???

Josh

>
> In looking at the latest draft-ietf-ips-fcovertcpip-01.txt
> document, it
> looks like Section 6.2 (below) could cover the ability to provide
> connectivity between N_Ports (the area that iFCP covers in
> great detail).
> May be it needs some additional work to diagram and explain
> how this is
> possible, but if that is the case, what additional
> capabilities does iFCP
> proposal provide? Would this not be a natual way to integrate the two?
>
> From draft-ietf-ips-fcovertcpip-01.txt:
> >   6.2 FC Device
> >
> >      The protocol encapsulation and mapping of the FC frame
> described
> >      in earlier sections applies equally to any pair of FC devices
> >      (e.g. switch-to-switch or host-to-storage subsystem) wishing to
> >      tunnel FC frames across an IP-based network.  Any FC routing
> >      protocol exchanges may still occur transparently to the FCIP
> >      devices.  It should be noted that Fibre Channel Primitive
> >      Sequences and Primitives are not exchanged between
> FCIP devices.
>
> Regards,
>
> Venkat Rangan
> Rhapsody Networks Inc.
> http://www.rhapsodynetworks.com
>