Cisco Systems MGX 8230 manual Cell Loss Priority

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.

	Cisco MGX 8230 Edge Concentrator Installation and Configuration
Release 1.1.31, Part Number 78-11215-03 Rev. B0, May 2001		2-25