S/UNI®-ATLAS-3200 Telecom Standard Product Data Sheet
Preliminary
10 Functional Description
10.1 Input and Output Interfaces
The S/UNI-ATLAS-3200 supports two kinds of signaling: UTOPIA Level 3, which is used for
transferring fixed-length ATM cells; and POS-PHY Level 3, which is used for transferring
variable-length packets. Applications that require the S/UNI-ATLAS-3200 to transfer mixed cell
and packet traffic should use POS-PHY signaling.
Independent of the UL3 or POS signaling, the S/UNI-ATLAS-3200 may operate in two modes:
the Ingress and the Egress mode. The S/UNI-ATLAS-3200 is typically deployed in pairs. One
chip of the pair receives cells/packets from PHY devices and sends them towards the traffic
manager/switch core. This chip is said to be in Ingress mode. The other chip of the pair receives
cells/packets from the switch core and sends them to the PHY devices. This chip is said to be in
Egress mode.
Thus, the S/UNI-ATLAS-3200 can be configured in four ways: UTOPIA or POS-PHY signaling,
and Ingress or Egress mode. The S/UNI-ATLAS-3200 is in Ingress POS-PHY mode on reset,
which is the state in which all UL3/POS pins that can be either inputs or outputs, are inputs. This
avoids contention on startup.
10.1.1 Ingress Mode with UTOPIA Level 3 Signaling
In this configuration, the S/UNI-ATLAS-3200 receives traffic from a PHY, and transmits traffic
to a traffic manager. This traffic consists of ATM cells, transferred using UTOPIA Level 3
signaling.
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-1990553, Issue 4
63
PMC [ PMC-SIERRA, INC ]
