Btm Control Mapping: Frames And Cells; Cell Loss Priority, Frame Relay To Atm Direction; Cell Loss Priority, Atm To Frame Relay Direction; Congestion Indication, Frame Relay To Atm Direction - Cisco BPX-BXM-155-8DX Installation And Configuration Manual

BTM Control Mapping: Frames and Cells

BTM Control Mapping: Frames and Cells
In addition to performing DLCI to PVC/VCC conversion, the network interworking feature provided
by the BTM in the IGX switch maps cell loss priority, congestion information, and management
information between Frame Relay and ATM formats as follows:

Cell Loss Priority, Frame Relay to ATM Direction

Each Frame Relay to ATM network interworking connection can be configured as one of the DE to CLP
mapping choices:
•
These 2 choices are not available on IGX switch NIW (network interworking):
•
•

Cell Loss Priority, ATM to Frame Relay Direction

Each Frame Relay to ATM network interworking connection can be configured as one of the CLP to
DE mapping choices:
•
This choice is not available:
•

Congestion Indication, Frame Relay to ATM direction

•

Congestion Indication, ATM to Frame Relay Direction

•

For PVC Status Management

The AIT/BTM does convert OAM cells to OAM fastpackets, and vice-versa, including the AIS OAM.
Also, "Abit" status is now propagated via software messaging.
The ATM layer and Frame Relay PVC Status Management can operate independently. The PVC status
from the ATM layer will be used when determining the status of the FR PVCs. However, no direct
actions of mapping LMI Abit to OAM AIS will be performed.
Cisco BPX 8600 Series Installation and Configuration
22-10
The DE bit in the Frame Relay frame is mapped to the CLP bit of every ATM cell generated by the
segmentation process.
CLP is always 0.
CLP is always 1.
If one or more ATM cells belonging to a frame has its CLP field set, the DE field of the Frame Relay
frame will be set.
Choosing no mapping from CLP to DE.
EFCI is always set to 0.
If the EFCI field in the last ATM cell of a segmented frame is set, then FECN of the Frame Relay
frame will be set.
Chapter 22 Configuring Frame Relay to ATM Network and Service Interworking
Release 9.3.0, Part Number 78-10674-01 Rev. D0, July 2001