> hi, > > A simple question. When would you ever use global source > and destination addresses for a neighbor solicitation. > And why?
For an NS it makes sense to use an IP source address that the peer will try to send packets to so that the NS (with a source link-layer address option) can create/update the neighbor cache entry on the peer. If you don't do this you'll end up with twice the number of ND packets as in A ---> NS --> B A <--- NA <-- B A now has NCE for B A ---> TCP --> B When B wants to respond it doesn't have a NCE for A A <--- NS <-- B A ---> NA --> B B now has NCE for A A <-- TCP <-- B Also, for NUD you want to probe the actual destination in the NCE by sending to that unicast address. Thus the destination in a unicast NS should be a global address if the NCE is for a global address. > IMO, link local addresses must be used. But RFC 2461 does > not say this. It just says an address configured to the > interface. That can mean global addresses. I saw such a > packet at Connectathon (going on in San Jose). RFC 2461 should say something consistent with the above somewhere. E.g section 7.2.2 and reading between the lines in 7.3.3+4.3. Any suggestions on how it can be made more clear? Erik -------------------------------------------------------------------- IETF IPng Working Group Mailing List IPng Home Page: http://playground.sun.com/ipng FTP archive: ftp://playground.sun.com/pub/ipng Direct all administrative requests to [EMAIL PROTECTED] --------------------------------------------------------------------