Update
We've identified the cause of the issue.
Node: ND-02, CN-01, and OctaWeb Telephony System
Description: We have been advised by our Network Providers that they suspect there has been a device outage on GTT Services, as traffic is no longer flowing via Telehouse North. The 2-3 minute outage experienced can be put down to any traffic flowing via THN to GTT being cut off in a non-graceful state, as well as BGP hold-timers expiring and route reconvergence. Our Network Providers as well as ourselves will continue to monitor for the next 24 hours, and will post any updates if required.
Monitoring Status: Identified