+The persistent id for the link-local address was added to conform to RFC 2472;
+such that if there's an EUI-48 available, use that to make up the EUI-64. As of
+now, the Solaris implementation extracts the EUI-48 id from the Ethernet's MAC
+address (the ethernet interface needs to be up). Future works might support
+other ways of obtaining a unique yet persistent id, such as EEPROM serial
+numbers, etc.
+
+There need not be any up/down scripts for ipv6, e.g. /etc/ppp/ipv6-up or
+/etc/ppp/ipv6-down, to trigger IPv6 neighbor discovery for auto configuration
+and routing. The in.ndpd daemon will perform all of the necessary jobs in the
+background. /etc/inet/ndpd.conf can be further customized to enable the machine
+as an IPv6 router. See the man page for in.ndpd(1M) and ndpd.conf(4) for
+details.
+
+Below is a sample output of "ifconfig -a" with persistent link-local address.
+Note the UNNUMBERED flag is set because hme0 and ppp0 both have identical
+link-local IPv6 addresses:
+
+lo0: flags=1000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4> mtu 8232 index 1
+ inet 127.0.0.1 netmask ff000000
+hme0: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 2
+ inet 129.146.86.248 netmask ffffff00 broadcast 129.146.86.255
+ ether 8:0:20:8d:38:c1
+lo0: flags=2000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv6> mtu 8252 index 1
+ inet6 ::1/128
+hme0: flags=2000841<UP,RUNNING,MULTICAST,IPv6> mtu 1500 index 2
+ ether 8:0:20:8d:38:c1
+ inet6 fe80::a00:20ff:fe8d:38c1/10
+hme0:1: flags=2080841<UP,RUNNING,MULTICAST,ADDRCONF,IPv6> mtu 1500 index 2
+ inet6 fec0::56:a00:20ff:fe8d:38c1/64
+hme0:2: flags=2080841<UP,RUNNING,MULTICAST,ADDRCONF,IPv6> mtu 1500 index 2
+ inet6 2000::56:a00:20ff:fe8d:38c1/64
+hme0:3: flags=2080841<UP,RUNNING,MULTICAST,ADDRCONF,IPv6> mtu 1500 index 2
+ inet6 2::56:a00:20ff:fe8d:38c1/64
+ppp0: flags=10008d1<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST,IPv4> mtu 1500 index 12
+ inet 172.16.1.1 --> 172.16.1.2 netmask ffffff00
+ppp0: flags=2202851<UP,POINTOPOINT,RUNNING,MULTICAST,UNNUMBERED,NONUD,IPv6> mtu 1500 index 12
+ inet6 fe80::a00:20ff:fe8d:38c1/10 --> fe80::a00:20ff:fe7a:24fb
+
+Note also that a plumbed ipv6 interface stream will exist throughout the entire
+PPP session in the case where the peer rejects IPV6CP, which further causes the
+interface state to stay down. Unplumbing will happen when the daemon exits. This
+is done by design and is not a bug.