Functional description
MPR-e and MSS-1c User Manual 3DB19901EFAA Edition 01 175
3.10.14.2 — Ethernet flows
All flows different from the TDM2TDM and TDM2ETH ones are managed as the standard
Ethernet packets:
• if 802.1D is enabled, only the destination address is considered to route the packets.
• if 802.1Q is enabled, the related management is performed looking the C-VLAN and
then, according to the destination address, each packet is switched to the correct port:
radio, user Ethernet or E1
• if 802.1ad (Q in Q) is enabled, the related management is performed looking the S-
VLAN and then, according to the destination address, each packet is switched to the
correct port: radio, user Ethernet or E1.
The bandwidth assigned globally to the radio interface to the Ethernet traffic is the
consequence, with a given radio capacity, of the number of E1 cross-connected on the radio
interface. Hence the available bandwidth for Ethernet flows will be the configured radio
bandwidth decreased by the bandwidth used by each TDM2TDM and TDM2ETH.
3.10.15 — Synchronization
3.10.15.1 — Synchronization overview for MSS-1c
TDM data flow is fragmented and the fragments are transmitted over a Packet Switched
Network (PSN);
The received fragments need to be reassembled in the original TDM data flow at the
“original bit rate”
Two main methods can be used to recover at the Rx site, the original bit rate:
• Differential clock recovery with or without the node timing: recalculation of the
original clock based on the time delta with respect to a reference clock that is
available at both Tx and Rx site (Differential: used in case of clock distribution on
the whole network. It’s more reliable than Adaptive; also used in TDM2TDM traffic
(MPR to MPR)). This method can be selected for each E1 stream.
Note: To configure these cross-connections a connected MPT is needed.
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