GFP provides a generic mechanism to adapt traffic from higher-layer client signals
over a transport network. GFP encapsulation is implemented according to
T1X1.5/2000-147.
The following GFP encapsulation are possible with EPL4_E14:
•
Mapping of Ethernet MAC frames into Lower Order SDH VC12–Xv (X = 1...63)
•
Mapping of Ethernet MAC frames into Lower Order SDH VC3–Xv (X = 1...9)
•
Mapping of Ethernet MAC frames into Higher Order SDH VC4–Xv (X=1..7)
LAPS encapsulation is implemented according to ITU-T X.86.
Advanced rate control
The EPL4_E14 option card supports advanced rate control in the ingress and egress
direction which allows to set a strict traffic limit (PIR), in combination with a hold-off
mechanism: Excess traffic is held off until the ingress or egress buffer overflows. In
case the ingress buffer fills above a certain threshold, pause messages are sent in the
reverse direction to hold off further traffic. This behaviour improves the TCP
throughput. Note that Pause messages can be only sent when the Pause mode is
enabled via the Lucent NMS.
Link Pass Through (LPT)
The EPL4_E14 option card supports the Link Pass Through (LPT) mode. On
point-to-point Ethernet Private Line connections, when GFP data encapsulation is used
throughout the network, the system identifies defects from the network ingress port to
the network egress port. The GFP-CSF mechanism is used to notify the egress side that
a loss of signal (synchronization) has occurred on the ingress port. Consequently, the
egress side can either turn off the laser at the egress (in case of an optical level) or
substitute an error pattern (for example, a /V/ ordered set for a 1000BASE-X). In
addition, an alarm is raised at the egress side which indicates the ingress side
condition. For more information about Link Pass Through, please refer to (LPT, see
). For additional information, please refer the TransLAN® Ethernet
SDH Transport Solution Applications and Planning Guide.
The EPL4_E14 option card supports Auto MDI/MDIX selection on all LAN ports.
Transmission rates
The following rates are supported with EPL4_E14:
•
Mapping Ethernet packets into VC12-Xv (X = 1...63)
•
Mapping Ethernet packets into VC3-Xv (X = 1...9)
•
Mapping Ethernet packets into VC4-Xv (X=1..7)
Flexible bandwidth assignment
The transmission capacity of the EPL4_E14 option card towards the cross-connect
matrix is 8 x VC4s. These can be freely assigned to 4 VCGs. There is a fixed 1:1
relationship from the 4 Ethernet ports to the 4 VCGs. For an illustrated description, see
“EPL4_E14 option card” (p. 2-18)
Product description
Introduction
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365-312-847R4.0
Issue 4, November 2006
Lucent Technologies - Proprietary
See notice on first page
2-17
