However, we now need cheap consumer routers that just work without any complex setup. The last thing we need is people having to type in IPv6 addresses in to anything!
Well, this is where we are. We have router manufacturers starting to make routers and asking us for what we need. We make an LNS (FB6000) for the ISP end and PPPoE router (FB2700) for end user end. At the moment we are like everyone else, expecting a static config on the FB2700, though we do make it a lot easier than most :-).
The trick is a way to tell the router a few key details :-
- Router link IPv6 address so it can talk to the internet (i.e. a proper IPv6) for things like setting clock, updating s/w, etc. This could use the LAN address though.
- IPv6 DNS server addresses so not having to rely on IPv4
- Prefix to announce on the LAN so equipment connected knows DNS and router and IPs
This is basically the information that was supplied using PPP for IPv4. On the LAN DHCP was typically used, and a prefix was not delegated but NAT used (ug!). So the obvious choice is to use PPP to provide these IPv6 details. IP6CP is already a PPP protocol and already used to define one parameter (interface 64 bit address). It could easily have more parameters.
However, there seems to be some suggestion of using DHCPv6 for this. I am at a loss why. Some suggestions of avoiding more than one protocol, but it is a pain for router manufacturers and LNS manufacturers to use so who is behind this?
- LNS already has IPv6 details by RADIUS as it needs these for routing and source filtering
- LNS already has PPP and knows how to handle and route PPP
- LNS already has IP6CP to negotiate interface address
- Adding extra IP6CP parameters is an easy change at LNS or router
- DHCPv6 means LNS has to accept FE80:: link local that it would normally drop/filter
- DHCPv6 on LNS has to pass these to IP/UDP layer but has to include interface details to identify source (not normally needed at UDP layer)
- DHCPv6 on LNS has to be able to reply to specific PPP link (not usually needed for UDP)
- DHCPv6 on LNS either needs this totally new DHCPv6 protocol, or, just as complex, a DHCPv6 relay
- DHCPv6 relay means DHCPv6 server needs IP allocation details as well as RADIUS does and they need to be in sync
- Router already has PPP and IP6CP and adding more parameters is easy
- DHCPv6 on router would need whole new DHCPv6 protocol adding
Anyone know CISCOs view on this? What will be in their LNSs?
Update: Thanks to Simon for tracking this down. Seems I am not alone...
These proposals cover the problem quite well and make specific proposals.