"Bad bgp identifier"

4271 specifies that bgp identifier must be a valid unicast ip address

So what is the larget 32 bit value expressed as a dotted quad that meets this requirement?

Is it the last address in class c? class e? Can 255.x.x.x be used?

Do all vendors implement this?

I understand that draft-ietf-idr-bgp-identifier-06.txt does away with the above requirements. Is this something I should ask vendors if they will support it?

Thanks,

Joe

Unicast currently ends at 223.255.255.255.
224.0.0.0/4 is multicast and I believe that
240.0.0.0/5
248.0.0.0/6
252.0.0.0/6 are listed as reserved for experimental purposes.

Owen

240.0.0.0/4 - This block, formerly known as the Class E address
    space, is reserved. The "limited broadcast" destination address
    255.255.255.255 should never be forwarded outside the (sub-)net of
    the source. The remainder of this space is reserved for future use.
    [RFC1700, page 4]