Subject: [Autoconf] MANET interfaces

From: Alexandru Petrescu <[email-masked]>
Date: Tue, 24 Apr 2007 17:33:07 +0200

MANET-arch document draft-ietf-autoconf-manetarch-01.txt defines MANET
interfaces.  I take several issues with it.

draft says:
> MANET Router (MR) an entity that has one or more MANET interfaces and
>  that engages in a MANET routing protocol.  A MANET router may also 
> have zero or more classic IP interfaces to which hosts may connect.

Is it sure that authors meant a MANET router can have zero classic IP
interfaces?  Or 1?  Because if it has 0 classical interfaces then it can
not connect, not in a classical way.

> 4.  MANET Interface Characteristics

Can a MANET Interface be a normal regular classical real interface?  Or
must it always be a virtual interface?  I think this should be
clarified.  I think the main definition of a MANET Interface should say
it can be either a real Ethernet interface or a virtual interface.  It
should be exemplified with interface types that people have run in MANETs.

I think the main characteristic, and probably the only fully agreeable,
is that a MANET interface is the one on which a MANET protocol is run.

> 4.2.1.  Semi-Broadcast Interface

This pictures how wireless routers rt1, 2 and 3 may have limited
visibility at link layer, although rt2 sees both rt1 and rt3.

This is a typical problem in wireless (I've personally first saw it in
wifi).

An IP router trying to achieve the role of rt2 will in no case 'forward'
packets, nor will it IP route packets between rt1 and rt3.  It will
bridge or repeat.

> The possibly unique set of adjacent nodes in each node often requires
>  nodes to forward packets out the same wireless interface as the one
>  over which they were received.

Because of above I think the node shouldn't 'forward' but 'bridge' or
'repeat' packets.  I don't think it should be solved at IP layer.

...

Figure 4 showing a MANET and how it splits uses the the abbreviation MN
for MANET Node.  But "MN" term is in wide use as Mobile Node (Mobile
IPv6), and defined in an RFC.  I suggest to call that a MANET router
instead.

Still on the characteristics of MANET interfaces.  I believe it should
be discussed whether or not the address and prefix of a MANET interface
are allowed (or are expected) to change during the lifetime of a MANET
network.

I personally think that most if not all the MANETs that have been built
until now have prefixes assigned statically (or manually) and the
prefixes and the addresses don't change on these MANET interfaces.  I
think this should be stated as such, that MANET interfaces don't change
their prefixes nor their addresses.

Alex

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