Margaret Wasserman wrote: > Oops... > > I made a mistake in the response. An anycast address can > only be assigned to a router (an IPv6 node that forwards > packets), not to a host. > > So, most Web Servers could not be assigned an anycast address. >
Yes that is what the spec says, but reality is always somewhat different. There is no technical reason that an anycast address could not be assigned to any group of hosts. The issue that must be dealt with is the scope of the routing knowledge about that group. If the knowledge is kept local to a private network, there is no problem. If the knowledge must be distributed globally for the service to work, there is a big problem. In between there are various trade-off's. The bottom line is that an anycast address is just a host route injected at multiple places. The global routing system can't deal with a massive number of host routes, while a local network is better positioned to manage the number of them within its own level of pain. If a regional service provider wanted to advertise anycast addresses for web services to its customers, it is free to do so. Where the spec tries to draw the line is that there should be no expectation that those addresses will work outside of a group of consenting networks. Tony > Sorry, > Margaret > > > At 08:28 AM 1/22/2003 -0500, Margaret Wasserman wrote: > > >Hi Digamar, > > > >Sorry for not replying earlier. > > > >>I have read the RFC reagrding the addressing in IPv6 and I > understood > >>that Web servers , routers , load balancers, Gateways and > Switches can > >>have either Unicast or Multicast or Anycast address. > > > >Any IPv6 node can have any of these types of addresses. All > nodes will > >have at least one unicast address (since every interface must have a > >link-local unicast address). Other addresses are optional, and will > >depend on the configuration of the network and the individual node. > >However, most nodes on the global Internet will have one or > more global > >unicast addresses. > > > >There is no either/or relationship between unicast, multicast and > >anycast addresses. A node may have all three, if it is > configured that > >way. > > > >Margaret > > > > > > > > > >-------------------------------------------------------------------- > >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] > >-------------------------------------------------------------------- > > > -------------------------------------------------------------------- > 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] > -------------------------------------------------------------------- > -------------------------------------------------------------------- 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] --------------------------------------------------------------------
