Loop Telecom AM3440 series, User Manual, Page: 8 / 70

CHAPTER 1 PRODUCTION DESCRIPTION
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1.2.1. Clock Recovery
Sophisticated TDM clock recovery mechanisms, one for each E1/T1 interface, allow end-to-end TDM
clock synchronization, despite packet delay variation of IP/MPLS/Ethernet network.
TDMoEthernet
supports the following clock recovery modes:
• Adaptive clock recovery
• External clock
• Loopback clock
The clock recovery mechanisms provide both fast frequency acquisition and highly accurate phase
tracking:
• Jitter and wander of the recovered clock are maintained at levels that conform to G.823/G.824 traffic or
synchronization interfaces. For adaptive clock recovery, the recovered clock performance depends on
packet network characteristics.
• Short-term frequency accuracy (1 second) is better than 16 ppb (using PPB reference), or 100 ppb
(using PPM reference)
• Capture range is ±90 ppm
• Internal synthesizer resolution of 0.5 ppb
• High resilience to the packet loss and mis-ordering, up to 5% of packet loss/misordering without
degradation of clock recovery performance
• Robust to sudden significant constant delay changes
• Automatic transition to hold-over is performed upon link-break events
1.2.2. Bundles
A bundle is defined as a stream of bits that have originated from the same physical interface. They are
transmitted from a TDMoEthernet source device to a TDMoEthernet destination device. For example,
bundles may comprise any number of 64 Kbps timeslots originating from a single E1, T1 or an entire
E3/DS3. Bundles are single direction streams, frequently coupled with bundles in the opposite direction
to enable full duplex communications. More than one bundle can be transmitted between two
TDMoEthernet devices. For E1/T1, the chip provides internal bundle cross-connect functionality, with
DS0 resolution. You can establish a cross-connect between different E1/T1 interfaces of TDMoEthernet
device, or within one interface of TDMoEthernet. Only one bundle can be defined for E3/DS3.
Up to 64 bundles are supported. Each bundle in the TDMoEthernet is transmitted using one of the
following payload type methods: AAL1, CESoPSN or SAToP. Each TDM over Ethernet
bundle/connection may be assigned to one of the payload types. For E1/T1, the chip provides internal
bundle cross-connect functionality, wit DS0 resolution. You can establish a cross-connect between
different E1/T1 interfaces of the TDMoEthernet device, or within one interface of the device.