ATM Layer: Virtual Circuits
VC transport: cells carried on VC from source to dest
- call setup, teardown for each call before data can flow
- each packet carries VC identifier (not destination ID)
- every switch on source-dest path maintain “state” for each passing connection
- link,switch resources (bandwidth, buffers) may be allocated to VC: to get circuit-like perf.
Permanent VCs (PVCs)
- long lasting connections
- typically: “permanent” route between to IP routers
Switched VCs (SVC):
- dynamically set up on per-call basis