Establishing Atm Channels; Virtual Channels; Local Links And Connections - 3Com CoreBuilder 7000 Operation Manual

5

Virtual Channels

Local Links and
Connections
E
STABLISHING
ATM is a connection-oriented transport service, much like a telephone.
Unlike Ethernet, where data is sent out on a common bus, ATM requires
that a path or virtual channel be established to carry the call from the
source station to the destination station before data transmission can
begin. A virtual channel may be established either manually through
management or automatically through the processes of signaling and
routing.
This chapter provides basic concepts and information about:


Virtual Channels


VP Tunneling


Signaling — External Links


Signaling AAL


Call Admission Control


UNI Signaling 4.0 Features


Routing — Internal Links


Physical-Link Failure Indicator
A virtual channel is a communications path that can carry a single call
from the source station to the destination station. The term virtual is used
because the channel does not necessarily correspond to a single physical
line and, in fact, usually passes through many different network devices
and cables before reaching its destination.
A virtual channel is built from a series of local links of two types:


External links between ports of adjacent ATM devices


Internal links between input and output ports of an ATM device
ATM C
HANNELS