Cisco Systems MGX 8220 Command/Response Mapping

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Cisco MGX 8220 Installation and Configuration
Release 5.0, Part Number 78-6430-03 Rev. D0, November 2003
Chapter Frame Relay Service Modules (FRSMs)
Frame Relay–to–ATM Direction
Each Frame Relay–to–ATM service interworking connectio n can be conf ig ured as one of t he foll o wi ng
Discard Eligibility (DE ) to cell loss priority (CLP) s c he mes:
•DE bit in the Frame Relay f r am e is m a p pe d to th e C LP bit of every ATM cell generated by the
segmentation process of the fram e.
•CLP is always 0.
•CLP is always 1.
ATM–to–Frame Relay Direction
Each Frame Relay–to–ATM service interworking connectio n can be conf ig ured as one of t he foll o wi ng
CLP to DE mapping sc he m es :
•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 priori ty opt io n i s acco mpli she d t hro ugh th e MGX 8 220 cnfchanmap (configure
channel map) command.
Congestion Indication
Frame Relay–to–ATM Direction
Each Frame Relay–to–ATM service interworking connectio n can be conf ig ured as one of t he foll o wi ng
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 fram e.
•EFCI is always 0.
•EFCI is always 1.
ATM–to–Frame Relay Direction
Frame Relay–to–ATM service interworking connection s u se the following EFCI to FECN /B E C N
mapping schemes:
•If the EFCI bit in the las t ATM cell of a se gmente d fr ame r ecei v ed is set to 1, th e FE CN of the Fra me
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.
Command/Response Mapping
Command/Response Mapping is provided in both directions.
Frame Relay–to–ATM Direction
The FRSM maps the C/R bit of t he r ece ived Fr ame Relay frame to the CPCS-UU le ast -significant bit
of the AAL5 CPCS PDU.