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.

The first “at risk” period is Monday 24th March from 1500-1600 for King’s Buildings (KB). Since KB is our disaster recovery site, nobody should be affected by any outages there, although you never know!

Based on what we learn from this we hope to announce firm migration dates for the Forum and Appleton Tower (AT) in the following two weeks (and hopefully after the working day, probably from 6pm)

tl;dr: KB network at risk for upgrades next Monday, other sites upgraded later, to be announced.

Router upgrades / Computing Systems by is licensed under a