RE: fcovertcpip - N_Port support.

[Charles Monia <cmonia@NishanSystems.com>]

Hi Folks:

I believe Murali has accurately characterized the differences in design
goals and technologies between iFCP and FCIP.

I am also in agreement with Murali's views regarding the advisability of
combining the two specifications.

Charles
> -----Original Message-----
> From: Murali Rajagopal [mailto:muralir@lightsand.com]
> Sent: Saturday, January 13, 2001 6:49 PM
> To: Joshua Tseng; Venkat Rangan; IP Storage Working Group
> Subject: RE: fcovertcpip - N_Port support.
> 
> 
> 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
> >
> 
>