Data Vccs - Avaya M-ACCF/SF User Manual

Chapter 1 Overview
Table 1.1
VCC Name
Control-
distribute

Data VCCs

Data VCCs carry data frames between LECs and between a LEC and the BUS.
Unicast data is normally sent from one LEC to another LEC by data-direct VCCs.
Data direct VCCs are set up dynamically in a SVC environment by a transmitting
LEC after ascertaining the ATM LEC destination address for the packet to be
transmitted. Once established, a data-direct VCC remains in place for transmission
of subsequent traffic between the two LECs. However, a data direct VCC that
remains unused for VCC-Timeout-period is released by the LEC.
A multicast data VCC pair (multicast-send and multicast-forward) are established
between a LEC and the BUS in order to allow the LEC to send and receive multicast
data. In addition, initial unicast data (data whose LEC destination has not yet been
ascertained by the transmitting LEC) is sent on the multicast-send VCC to the BUS
which forwards it to all other LECs in the same ELAN. Characteristics of the data
VCCs are summarized in the following table:
Table 1.2
VCC
Name
Data-
direct
Multicast-
send
Multicast-
forward
6
Control VCCs (Continued)
From/To
LES==>LEC
Data VCCs
Information
From/To
carried
LEC<==>LEC Point-to-point
Unicast data
between LECs
LEC<==>BUS LEC sends
multicast and
initial unicast
data to BUS
BUS==>LEC BUS distributes
data traffic to
LECs
Avaya M770 M-ACCF/SF ATM Access Modules User's Guide
Information carried
LES distributes
control traffic to
LECs, including
LE_ARP information
Initialize
d by
LEC
LEC
BUS
Initialized
Duration
by
LES Membership
of LEC in
ELAN
Duration
Established by
need and released
when unused for
VCC-Timeout-
.
period
Membership of
LEC in ELAN.
Membership of
LEC in ELAN.