Advance Data Sheet
September 2001
CelXpres
T8208
ATM Interconnect
1
Product Overview
(continued)
CelXpres
T8208 in a system with dual backplane cell buses using shared UTO-
PIA mode. In this configuration, both T8208 devices on each card receive cells from the UTOPIA bus, and each
device uses its translation table to determine if the cell should be transmitted on its backplane cell bus. In the
egress direction, each T8208 device receives cells from its cell bus to transmit on the UTOPIA bus. MPHY arbitra-
tion and queue priorities are resolved using a six-wire interface between the two devices. Although a single ATM
virtual connection is not typically established on both backplane cell buses simultaneously, no restrictions exist for
a single PHY utilizing both backplane cell buses for different virtual connections supporting higher throughput from
two bus interfaces. Redundant bus configurations can be supported in the event of a bus failure with T8208
devices by configuring one device to assume bus responsibility from the other.
DOWNSTREAM
BUFFERING
UPSTREAM
TRANSLATION
UTOPIA
T8208
UTOPIA
PHYs
T8208
DOWNSTREAM
BUFFERING
UPSTREAM
TRANSLATION
DOWNSTREAM
BUFFERING
UPSTREAM
TRANSLATION
UTOPIA
T8208
BACKPLANE
BUS
T8208
UTOPIA
PHYs
DOWNSTREAM
BUFFERING
UPSTREAM
TRANSLATION
0041b
Figure 2. Dual Bus Implementation
Agere Systems Inc.
11
AGERE [ AGERE SYSTEMS ]
