*	"SUN_68K" should really be "MIT_68K".

*	If more than one link leads to a domain, then a link is chosen
	at random, despite knowing which link the message just arrived on.
	(Only a problem when local domains have been incorrectly configuered).
	- Need a "for each link in, bitmap of links out" table for domains.
	-- Quickfix by using explicit routing.

*	PBUFSIZE should be dependant on the speed of the link, as it is,
	when the link speed is low, message turn-around is delayed on the
	opposite channel.
	-- Quickfix for sites with slow links (eg CSIRONET) by specifying
	   a maximum value of 512 (not 8192!).

*	When a link comes up, then the new status is broadcast to the
	primary domain of the node. This means that nodes in sub-domains
	will not get the message. EG: if a major node in is "cs" and "oz"
	with "oz" as the primary, and it is linked to a minor node just in
	"cs", then the minor node will not see UP messages for other links
	to the major node.
	- Need a "*.<hierarchy>" type broadcast addressing scheme.
	-- Quickfix by ensuring that all nodes in sub-domains
	   are also members of the local major-domains.
