zl50118gag2 Zarlink Semiconductor, zl50118gag2 Datasheet - Page 56

• Manufacturer Part Number: zl50118gag2
• Description: 32 Channel 1 T1/e1 Cesop Processor With Single Ethernet Interface
• Manufacturer: Zarlink Semiconductor

ZL50115/16/17/18/19/20
Data Sheet
6.9
TDM Formatter
At the receiving end of the packet network, the original TDM data must be re-constructed from the packets
received. This is known as re-formatting, and follows the reverse process from the Payload Assembler. The TDM
Formatter plays out the packets in the correct sequence, directing each octet to the selected timeslot on the output
TDM interface.
When lost or late packets are detected, the TDM Formatter plays out underrun data for the same number of TDM
frames as were included in the missing packet. Underrun data can either be the last value played out on that
timeslot, or a pre-programmed value (e.g., 0xFF). If the packet subsequently turns up it is discarded. In this way, the
end-to-end latency through the system is maintained at a constant value.
Contexts in the Packet to TDM direction are placed in the UPDATE state when they are opened, pending first
packet arrival. If a packet never arrives the context will remain in the UDPATE state. ZLAN-202 describes the
procedure to close receive contexts in the UPDATE state.
6.10
Ethernet Traffic Aggregation (ZL50118/19/20 only)
The ZL5011x allows native Ethernet traffic received on the customer side Fast Ethernet port to be aggregated with
the CESoP traffic from the TDM interface to the provider side Gigabit Ethernet port. Likewise, traffic from the
provider side Gigabit Ethernet port may be split between CESoP traffic destined towards the TDM interface and
native Ethernet traffic destined towards the customer side Fast Ethernet port. This functionality is achieved by
correctly programming the task manager and packet classifiers for flow 11.
From the provider side Gigabit Ethernet port to the customer side TDM and Fast Ethernet interfaces there is
sufficient internal bandwidth to avoid any prioritization issues. From the customer side TDM and Fast Ethernet
interfaces towards the Gigabit Ethernet ports the TDM CESoP traffic may be sent to a higher priority output queue
(there are four output queues total) than the native Fast Ethernet traffic. In this way the access to the provider side
Gigabit Ethernet port is prioritized for TDM traffic over native Ethernet traffic.
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Zarlink Semiconductor Inc.