Virtual Circuits - HP auroraTempo User Manual

FECN
Forward Explicit Congestion Notification. This is used
for congestion indication - please refer to Congestion
Control later in this Chapter for further information.
BECN
Backward Explicit Congestion Notification. This is
used for congestion indication - please refer to
Congestion Control for further information.
DE
Discard Eligibility Indicator. This bit is used in
congestion control to prioritize frames.
EA
Extended Address. In the event that over a thousand
virtual circuit addresses on an interface are
required, the address extension bit allows for more -
about 268 million.
DL-CORE Control Indicator (D/C)
This bit is set to 0 to indicate that the octet contains
DLCI information; it is set to 1 to indicate that the
octet contains DL-CORE control information. At
present only DLCI information is held and the
indicator has only been included to allow for future
expansion.

Virtual Circuits

A virtual circuit is a logical path which traffic follows
through the network. A virtual circuit is determined by
its end points - the path between these points is left to the
network to determine. There are two types of virtual circuit
- PVCs and SVCs.
Issue 1a - 10/99
Introduction to Frame Relay
8-11