The Routing Over Large Clouds Mailing List Archive by date

[Curtis Villamizar <curtis@ans.net>]

In message <199510242337.QAA25871@hubbub.cisco.com>, Yakov Rekhter writes:
> > 
> > A new term was needed for "a specific subset of the internetwork
> > topology in which the underlying network does not prevent all hosts or
> > routers from being directly reachable without IP forwarding to an
> > intermediate party".  This has nothing to do with addressing and any
> > overlap with an address prefix, whether intentional or coincidental,
> > does not define the region.  The term "address prefix region" is
> > absolutely the wrong term.  The old terms commonly used were "NBMA
> > network" or "subnet in the OSI sense".  You need to pick a term that
> > clearly reflects what you are describing.
> > 
> > You are proposing to decouple addressing and then defining a term that
> > couples "aka NBMA network" with an address prefix.  Fix the ommision
> > of hop-by-hop QoS and one hop off the NBMA procedures and get rid of
> > the coupling with address prefix entirely and I'll wholeheartedly
> > support the draft.
> 
> I'll certainly include the reference to the hop-by-hop QoS. Likewise, I'll
> add "one hop off the NBMA procedures".  However, the address prefix has to
> be retained, as it provides coupling between hosts and routers on the NBMA
> network (a router on the NBMA network may act as a last hop for only a subset
>  
> of all the hosts connected to the NBMA network). 
> 
> Yakov.


Yakov,

I understand this paragraph to mean the subnet behind the router
should fall into the same address prefix as prefix covering the NBMA.
This is assumiong that an address prefix match is being used as the
means to determine direct reachability.  I do not support the document
advocating this.  I do support the document mentioning that this is
one possibility, though its applicabiulity may be limited (in much the
same way the applicability of static routing is limited).

The qualifier you mention above then becomes: If an address prefix is
used as the means to determine direct reachability, then any subnet
that is off the NBMA but behind a router on the NBMA must fall within
a prefix that is thought to directly reachable on the NBMA.  The
physical address of the border routers must be associated with it's
own address plus any others that it is providing proxy almost-direct
reachability for.

I'd prefer if you left this out entirely and let another draft
describe the pros and cons of using an address prefix as a means to
determine direct reachability on an NBMA.

Curtis