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Cisco MGX 8230 Edge Concentrator Installation and Configuration
Release 1.1.31, Part Number 78-11215-03 Rev. B0, May 2001
Chapter 2 Module and Service Descriptions
Frame Relay Service Modules
Cell Loss Priority
In addition to frame-to-cell and DLCI-to-VPI/VCI conversion, the SIW feature maps cell loss priority
(CLP) and congestion information from Frame Relay-to-ATM formats and is FRF.8-compliant. It
provides full support for routed and bridged PDUs, transparent and translation modes, and VP
translation. The CLP and congestion parameters can be modified for individual connections with the
cnfchanmap command.
Frame Relay–to–ATM Direction
Each Frame Relay– to–ATM service interworking connection can be configured as one of the following
Discard Eligibility (DE) to Cell Loss Priority (CLP) schemes:
• DE bit in the Frame Relay frame is mapped to the CLP bit of every ATM cell generated by the
segmentation process of the frame.
• CLP is always 0.
• CLP is always 1.
ATM–to–Frame Relay Direction
Each Frame Relay– to–ATM service interworking connection can be configured as one of the following
CLP to DE mapping schemes:
• If one or more ATM cells belonging to a frame has its CLP set, the DE field of the Frame Relay
frame will be set.
• DE is always 0.
• DE is always 1.
Setting up the cell loss priority option is accomplished through the MGX 8220 cnfchanmap (configure
channel map) command.
Congestion Indication
Frame Relay–to–ATM Direction
Each Frame Relay– to–ATM service interworking connection can be configured as one of the following
Forward Explicit Congestion Notification (FECN) to Explicit-Forward Congestion Indicator (EFCI)
schemes:
• FECN bit in the Frame Relay frame is mapped to the EFCI bit of every ATM cell generated by the
segmentation process of the frame.
• EFCI is always 0.
• EFCI is always 1.
ATM–to–Frame Relay Direction
Frame Relay– to–ATM service interworking connections use the following EFCI to FECN/BECN
mapping schemes:
• If the EFCI bit in the last ATM cell of a segmented frame received is set to 1, the FECN of the Frame
Relay frame will be set to 1.
• BECN is always set to 0.
• Setting up the congestion indication option is accomplished through the cnfchanmap (configure
channel map) command.