3. General Configuration Recommendations
3.1. IPv4 ARP / IPv6 Neighbor Timeout
Each equipment vendor implements its own maximum ages for the IPv4 ARP and IPv6 neighbor caches. The values vary widely and in at least one case (Linux) it is not a constant.
Low ARP timeouts can lead to excessive ARP traffic, especially if the values are lower than the BGP KEEPALIVE interval timers. On the other hand, long timeouts can theoretically lead to longer downtime if you change equipment (since your peers still have the old MAC address in their ARP cache). With BGP this is unlikely to happen because your router will start re-establishing BGP sessions as soon as it is back up, causing its peers to update their ARP cache as well.
We recommend setting the ARP cache timeout to at least two hours, preferably four (240 minutes). See the sections on specific equipment vendors for examples.
3.2. Peering LAN Prefix
The IPv4 prefix for the AMS-IX peering LAN (195.69.144.0/23) is part of AS1200, and is not supposed to be globally routable. This means the following:
Do not configure “network 195.69.144.0/23” in your router's BGP configuration (seriously, we have seen this happen!).
Do not redistribute the route, a supernet, or a more specific outside of your AS. We (AS1200) announce it with a no-export attribute, please honour it.
In short, you can take the view that the Peering LAN is a link-local address range and you may decide to not even redistribute it internally (but in that case you may want to set a static route for management access so you can troubleshoot peering, etc.).