Enterasys Networks X-PeditionTM manual Frame Relay Features, Multi-Protocol Encapsulation

Frame Relay Features

Frame Relay Features

The XSR supports the following FR features:

•The XSR acts as a DTE/DCE device in the UNI (User Network Interface) interface, supporting FR PVC connections (NNI functionality is not supported)

•10-bit DLCI addressing using a 2-byte DLCI header (3- and 4-byte headers are not supported)

•Rate enforcement (CIR) with automatic rate fallback via traffic/adaptive shaping when the network is congested. Automatically restores to normal rates when congestion is removed

•Congestion control by Backward Explicit Congestion Notification (BECN). The XSR does not send packets with the BECN bit set

•Discard Eligibility (DE) bit - traffic is counted as it is received

•Three standard LMIs: ILMI (FRF1.1) ANSI Annex D, CCITT Annex A. Also supported: Auto LMI detect and None. The Full Status Continue Report type as defined by Annex A of FRF1.2 allowing LMI status messages to be broken into small sizes, is not supported since it is relevant only if more than 300 DLCIs are supported on one physical interface

•Multi-protocol interconnect over FR (RFC-2427). IP is supported

•Frame Relay Inverse ARP per RFC-2390

•LMI DCE support includes Asynchronous Status Messages.

•Auto and ILMI support 190 DLCIs per interface. Other LMI protocols support 300 per interface.

•Multiple logical interfaces over the same physical FR port (sub-interfaces)

•Quality of Service: standard FIFO queuing, or IP QoS on DLCIs

•Industry-standard CLI and statistics

•Maximum PDU size of 1536 bytes

•End-to-end packet fragmentation per FRF.12

•SNMP support per RFC-2115

•Traffic shaping

The XSR proscribes the following maximum configuration limits:

•1000 FR interfaces or sub-interfaces per node

•1000 DLCIs per node

•30 sub-interfaces per FR interface

•300 PVCs per FR interface for LMI ANSI, Q933A, NONE

•190 PVCs per FR interface for LMI AUTO, ILMI

•300 FR map-classes

Multi-Protocol Encapsulation

XSR supports encapsulation of multiple protocols - a flexible way to carry many protocols via FR. This method is useful when it is necessary to multiplex/de-multiplex across one FR connection, as described by RFC-2427, which defines a generic, end-to-end encapsulation mechanism for devices to communicate many protocols over a single port.

XSR User’s Guide 9-3