When evaluating a carrier for your MPLS network or IEPL, you may find that some carriers will only provide transit delay (latency) statistics from their PE to PE, not from the customer edge to customer edge. The general rule is to add a local loop delay metric for each side of the path in question to calculate latency in full.
In general, the following latency numbers are safe to use to the local loops:
- < 100 miles or 161 km: 10 ms
- >100 miles ( 161 km) and <300 miles or 483 km: 30 ms
- >300 miles (483 km) and <500 miles or 805 km: 39 ms
- >500 miles and <800 miles: 50ms
- 801 to 1000 miles: 60ms
- 1000 miles: 80ms
Remember: these are loop lengths, not straight line distance “as the crow flies”. Understand what your latency numbers will really be so you understand what you are paying for.