Virtual circuits
call setup, teardown for each call before data can flow
each packet carries VC identifier (not destination host ID)
every router on source-dest path s maintain “state” for each passing connection
- transport-layer connection only involve two end systems
link, router resources (bandwidth, buffers) may be allocated to VC
- to get circuit-like perf.
“source-to-dest path behaves much like telephone circuit”
- performance-wise
- network actions along source-to-dest path