Subject: RE: A fundamental question

From: "Lyndon Ong" <[email-masked]>
Date: Thu, 03 May 2001 11:40:35 -0700

On Thu, 3 May 2001 11:35:08    Naidu, Venkata wrote:
>Hi David
>[snip]
>-> ATM's routing and signaling protocols are closely tied to ATM's
>-> addressing architecture.  These protocols are not based on 
>-> IP, and they
>-> do not scale up to networks the size of the internet.  
>
>No David, These (ATM Signaling/Routing) protocols are very much designed
>to scale for networks as large as 'I'nternet. Esp designed keeping in mind
>with the growth of the Internet & addressing. But they didn't get
>(we didn't give) chance to let them prove.

If you compare PNNI routing vs. OSPF and PNNI setup (Q.2931) vs.
RSVP-TE, I find it also difficult to see some major difference in
scalability.  If anything, RSVP-TE has more scalability problems due
to the refreshes, which people are now trying to fix.

>-> ATM is not an IP protocol.

No argument there :o)  

Cheers,

L. Ong

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---

From: David Charlap <[email-masked]>
Date: Thu, 03 May 2001 15:21:26 -0400

Lyndon Ong wrote:
> 
> If anything, RSVP-TE has more scalability problems due to the
> refreshes, which people are now trying to fix.

RSVP-TE, as documented in the lsp-tunnel-08 draft, and RSVP as
documented in RFC 2205 have scalability problems, as you say.

But the solution already exists.  If reliable message delivery (part of
RFC 2961) is used in conjunction with the Hello mechanism (from the
RSVP-TE draft), then refresh intervals may be increased to extremely
long durations (days or weeks if you like) without breaking
functionality.

Of course, both of these features must be active for this to work. 
Without Hellos, you need a short refresh interval in order to detect
soft failures (that is, failures which don't result in a loss of carrier
on the interface).  Without reliable message delivery, you need a short
refresh interval to compensate for any lost packets.

IMO, RSVP-TE with the reliable message delivery extension, should be
scalable to the exact same degree that CR-LDP is.

-- David