🚀 go-pugleaf

	From: Sam Wilson <ercm20@festival.ed.ac.uk>
	Subject: Cisco, SMDS and multiple LISs
	To: cisco@spot.colorado.edu
	Reply-To: Sam.Wilson@edinburgh.ac.uk
	Message-Id: <9301281049.aa25796@uk.ac.ed.festival>
	Status: RO
	
	Looking for a snippet of technical advice...
	
	I'm involved in a project looking at how we might set up a large
	SMDS-based IP network.  One of the issues is whether we run multiple
	Logical IP Subnets (LISs) or one large LIS.  Before you say anything I'm
	not looking for advice on that at the moment! RFC 1209 recommends that
	IP-over-SMDS equipment should allow multiple LISs on the same SMDS
	interface using different E.164 group addresses (thus allowing a router
	between LISs to use a single i/f).  Some of my colleagues who met Cisco
	people recently say that the Cisco folk said that's what Cisco does. 
	
	Unfortunately there's no trace of this in the manual: I have the 9.1
	Router Products Configuration and Reference and have also looked at the
	Errata and 9.1(1) and 9.1(2) release notes but none shows any method of
	setting multiple group addresses.  Is this an undocumented feature or is
	it planned for a future release? If the latter then which and when?

SMDS Multi-LIS is planned for a major release after 9.1.  It has been 
tested, in-house in an experimental setup.  It''s not a 9.1 feature.
	
	For what it's worth the command to set the group address is
	
	   smds multicast ip <smds-group-addr>
	
	I'd have expected
	
	   smds multicast ip <smds-group-addr> [<ip-net> <mask>]

Correct.  The implementation of SMDS Multi-LIS supports the command
you describe above exactly.  When the [<ip-net><mask>] is left out of the
command, the multicast address is automatically associated with the net &
mask of the primary IP address on that interface.
	
	
	Sam Wilson
	Network Services Division
	Computing Services, The University of Edinburgh
	Edinburgh, Scotland, UK

rlfs@cisco.com