Re: Re: xPL bridging loop prevention

[Mal Lansell <mal@xxxxxxxxxxx>]

One of the main drivers behind the xPL design is the ability for the
protocol to be used by embedded devices with tiny amounts of available
memory.  That's why the protocol lacks some things that may make it more
robust.

One approach to the bridge loop problem, without needing to change the
protocol, would be to broadcast a special test message when you first
establish a connection to another bridge.  If you get it back with a hop
count > 1, you know there is a loop and can pop up a warning dialog.

Mal

Mark Hindess wrote:

>
> It would be possible to do reliable duplicate detection if each
message
> contained a sequence number - an incrementing integer for instance.
> Since you could hash the source and sequence number to get something
> that was "unique" - at least until the sequence number
overflowed back
> to zero by which time you'd have cleared the cache.
>
> It should be noted that UDP transfer does not guarantee that you wont
> get duplicates even without any bridges so strictly they should be
> handled gracefully anyway.  Of course, in practice this isn't really
> a problem - just as UDP's lack of assurances about order (or indeed
> delivery at all) tend not to be an issue when working within a single
> subnet.
>
> Whether this sort of thing becomes an issue really depends on whether
it
> is hoped/intended for xPL to grow beyond simple subnets and perhaps
one
> or two bridges.
>
> Regards,
> Mark.
>