Bob,
I wonder if it is likely that some of the confusion relating to
"multi-link subnets" that Dave tries to address, in the draft below,
comes from a disagreement about the definition of a "link"?
In Dave's draft, link is defined as "generally used to refer to
a topological area bounded by routers which decrement the IPv4 TTL or
IPv6 Hop Limit when forwarding the packet."
Outside of a strictly layer three context, this is simply not
true. However, it works for router folks because - even if a router
does have multiple interfaces into a single subnet (or collection of
subnets), the router "bridges" between those (two or more) links.
This can be simply modeled as -
_________|__________________________________
| | |
| | .-----(link-2)---+----
| .-+-. .-+-. |
--+-------+ R +--(LINK-1)---+ B +---(link-4)---+----
| `-+-' `-+-' |
| | `-----(link-3)---+----
|_________|__________________________________|
|
In this model, LINK-1 is as Dave's draft defines it. For this
reason, it is shown in upper-case. The use of the term "link" for
the link-2, link-3 and link-4 (clearly in lower-case in the figure)
is just as legitimate a use of the term - but in a layer two sense,
only. If we don't call the connections between bridges links, what
do we call them?
Hopefully, it helps to look at this model, because it should
help to highlight the essential layer-two nature of having multiple
interfaces connecting to the same subnet(s). By using a bridging
logical function to separate the LINK (per Dave's definition) from
the physical interfaces connecting to a subnet (set), issues with
layer two propagation in that subnet are resolved by that function.
--
Eric
--> -----Original Message-----
--> From: Bob Hinden [mailto:[EMAIL PROTECTED]
--> Sent: Wednesday, April 05, 2006 4:24 PM
--> To: Stephen Sprunk
--> Cc: IPv6 WG
--> Subject: Re: Ethernet as a shared (not broadcast) network?
-->
... [SNIP] ...
-->
--> Bob
-->
-->
--> >> Dave Thaler also wrote a draft on the general topic that was
--> >> presented at the internet area meeting in Dallas:
--> >>
--> >> Issues With Protocols Proposing Multilink Subnets
--> >>
--> >>
http://www.ietf.org/internet-drafts/draft-thaler-intarea-multilink-subnet-is
sues-00.txt
--> >
--> > Very good reading; thanks for the pointer.
--> >
... [SNIP] ...
-->
-->
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