Cell Relay Archive

[georgem@nntp.best.com (George Marshall)]

: > IISP (Forgotten the acronym, but it's basically PNNI phase 0) supports
: > SVC's between switches, which adds SVC-originated payload VC's, and
: > implies a signaling channel between the swithes to forward connection
: > setup messages, done with basically UNI signaling. IISP propagates no
: > routing information between switches, so the switches must be
: > configured with static routes.  Note: some vendors may refer to this as
: > PNNI, it's what most switches are running today, although again there
: > is little SVC in the WAN.[snip]

: What specifically is the difference between IISP and PNNI Ph 0?  I
: had assumed for all practical purposes they were the same, but at a
: recent product meeting with Vendor C the claim was that they had the
: only PNNI compliant switch on the market - I had a hard time
: swallowing that, but I have been wrong before.

There is no difference - originally, there was PNNI phase 0 and PNNI
phase 1, but for various reasons that may be hard to understand unless
you follow the politics of standards (and standards-like) groups,
PNNI-ph 0 was renamed IISP (OK, I went and looked it up: Interim
Inter-Switch Signaling Protocol).  So PNNI ph 0 does not technically
exist, but in fact it's common in the industry to refer to an IISP
implementation as PNNI.  

Since the PPNI (real PNNI - phase 1) spec has now been completed, 
it's certainly technically possible for a vendor to have a 
PNNI-compliant switch now, but absent the usual year-long process of 
vendor interoperability testing, it may not have all that much 
significance.   Ya just gotta ask what they mean by "PNNI compliant".

If multi-vendor interoperability is what you're looking for, it's
reasonable to plan on using IISP until [late] sometime next year.

Regards,

George Marshall
---
George Marshall  george.marshall@zeitnet.com   ZeitNet/Cabletron West  
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