IPv6 on AAISP Broadband

This is how we route and assign IPv6 on DSL connections.

Customers are allocated a /48 block of addresses - this is usually per customer, and so a customer with multiple circuits or sites will have a /64 allocated from the larger /48 block. A /48 contains 65536 /64's and a /64 subnet is 18 million trillion addresses.

(Here, CPE refers to the router belonging to the customer which is being used at their end of the broadband line.)

When the CPE logs in and negotiates PPP we use IPV6CP to assign an IPv6 'WAN' address. This address is a single IPv6 address in the form of:

2001:8b0:1111:1111:[your IPv4 WAN in HEX]

At this point we will also be routing any IPv6 blocks to this WAN address. Usually a line will have at least one /64 block.

We also respond to DHCPv6 Prefix Delegation (PD) from the CPE and we'll tell the CPE one of the /64 Blocks. -this may be requested multiple times by the CPE.

The CPE will also assign itself a Link Local address in the form of FE80::, and will be based on the MAC address of the interface.

Example Logs

PPP logs can be viewed from the control pages, it's the LNS Log button. Example:

l2tp-rx T20-1566-81.145.121.212 S6694-2278 PPP Tx 8057:IPV6CP 01 00 000E ConfReq 01:I/F 0A 02:03:97:ff:fe:05:c0:00 [CIRCUIT ID] [LOGIN]
l2tp-rx T20-1566-81.145.121.212 S6694-2278 PPP Rx FF03 8057:IPV6CP 01 00 000E ConfReq 01:I/F 0A 02:03:97:ff:fe:0f:00:02 [CIRCUIT ID] [LOGIN]
l2tp-rx T20-1566-81.145.121.212 S6694-2278 PPP Tx 8057:IPV6CP 02 00 000E ConfAck 01:I/F 0A 02:03:97:ff:fe:0f:00:02 [CIRCUIT ID] [LOGIN]
l2tp-rx T20-1566-81.145.121.212 S6694-2278 PPP Rx FF03 8057:IPV6CP 02 00 000E ConfAck 01:I/F 0A 02:03:97:ff:fe:05:c0:00 [CIRCUIT ID] [LOGIN]
l2tp-rx T20-1566-81.145.121.212 S6694-2278 Routes 2001:8b0:XXX::/64 2001:8b0:1111:1111::XXX/128 [CIRCUIT ID] [LOGIN]