VPI and VCI
8
7
6
5
4
3
2
1
GFC* / VPI
VPI
VPI
VCI
VCI
VCI
PTI
HEC
CLP
VPI and VCI are virtual connection identifiers (used for switching or relaying the cells to the correct destination)
Physical
layer
connection
(e.g. STM-1)
VPI 1
VPI 2
VCI 1
VCI 2
Multiplexing in AAL 2
Multiplexing in ATM layer