The "fixed prefix" mean that the ISP provides each client with at least a /64 prefix, preferably a /56 or /48 (this is the equivalent of "fixed IP" for IPv4).
Most professional ISPs do this; those currently known to do this are:
- RCS-RDS (Romania) - offering both a /128 address and optionally a /64 PD via DHCPv6 (sla_len 0 in dhcp6c)
- Comcast (USA) - DHCPv6: /128 for the immediate device (router) and a /64 prefix delegation. Requires wide-dhcpv6-client configured with "option 'na' '1'" in /etc/config/dhcp6c i.e. set Non-Temporary Address. Without changing the "na" option you will not get an address assigned to your WAN interface.
- Telecom Italia (Italy) give a /64 dinamic subnet
- Telekom Deutschland/DTAG with "IP-Anschluss" - a single /64 prefix for wan (proto dhcpv6) and a /56 for lan via 6relayd (ootb at least since r37493 barrier braker (trunk)) (to poll a RA use 'rdisc6 pppoe-wan'); see https://dev.openwrt.org/ticket/13943
doc/howto/ipv6.isp.txt · Last modified: 2013/07/26 18:04 by axelb