The addresses of all loopback and point-to-point addresses are entered into DNS in a special format. A script configured to allow zone-transfer of “ipv6.funet.fi” zone fetches this information and digs out the IP addresses which should be in use. The pinger periodically (once in five minutes) checks that the links (including the links to customers and the peers) are up and responding; if not, it sends an alert.

BGP and IS-IS adjacencies are also monitored using a tool which collects syslog warnings sent from routers to a central syslog server. If adjacencies or sessions flap, this can be noted in the monitoring page.

All routers and links are collected to a custom network map/monitoring tool, where the traffic levels and similar can be monitored easily.

A challenge in the dual-stack infrastructure is getting a feel how much traffic on the links is IPv4 and how much IPv6. As of this writing, there are no good mechanisms to get that. When IPv6 MIBs are complete and are implemented, getting such measurements may be easier.

The performance has not been rigorously tested, as the Junipers include a hardware IPv6 forwarding capability. When Cisco’s performance issues were noticed, and CEFv6 was tested, Funet also briefly tested the backbone network’s IPv6 forwarding capabilities; a PC with Gigabit Ethernet interface could not send enough traffic to cause any impact on the network, which was indeed what was expected.