Outline — full article in progress
This page has the structure and introduction. The full article is being written by the network team. In the meantime, ask us directly.
ISDN is being switched off across most of Europe and parts of Asia, and the teams still running E1 or T1 circuits are being pushed to SIP whether they planned to or not. This article compares the two on cost, quality and resilience, then gives a migration checklist that avoids the usual cut-over surprises. For the basics, start with what a SIP trunk is.
Cost comparison
- Line rental per E1/T1 versus pay-per-minute SIP
- Hardware: ISDN cards and gateways versus none
- International rates on incumbent telcos versus wholesale
Call quality
- Bandwidth and codec choice
- Why QoS matters on the access line
Resilience and failover
- Single site versus multi-site failover
- Backup routes and call forwarding
Migration checklist
- Porting existing numbers
- Running PRI and SIP in parallel
- Testing fax, alarms and lift lines