As part of the critical upgrade from SL7 to Ubuntu, we are replacing the core Linux routers serving each of our sites over the coming weeks.

The Linux routers are our edge (and sometimes internal) firewalls as well as providing routing between our subnets and EdLAN, and onwards to the internet. They are connected to our core switches and provide 10Gbps throughput for external traffic. We have redundant pairs at each site (plus some other backups) all of which need to be upgraded.

In order to upgrade the routers, we need to announce the school subnets in BGP (Border Gateway Protocol) to EdLAN (the wider University network), and then instruct client machines to use them as their gateway. Since there is obviously a period between these two steps, there is a risk of asymmetric routing which typically upsets stateful firewalls. We have a plan to synchronise the connection tracking tables of the old and new routers so that no outage should be observed. However, like all plans, there is some risk and so we are announcing this at risk period.

If you do observe connection issues, you can resolve them by rebooting your machine, or, if you are able to do so, refresh your DHCP lease to get the address of the new router.

The next upgrade is Tuesday 20th May at 6pm. This affects Appleton Tower.

Router upgrades – Tuesday 20th May 6pm / Computing Systems by is licensed under a