Hdlc, Frame relay – Cyclades PR1000 User Manual

Page 54

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Chapter 8 - Data-Link Protocols (Encapsulation)

Cyclades-PR1000

54

HDLC

This data-link protocol is a proprietary alternative to PPP. It has only one parameter, the

HDLC Keepalive Interval

.

This is the time interval between transmission of Keepalive messages. The receiver of these messages must send
keepalive messages with the same frequency or will be considered inoperative.

Frame Relay

FR supports multiple connections over a single link. Each data link connection (DLC) has a unique DLCI (data link
connection identifier). This allows multiple logical connections to be multiplexed over a single channel. These are
called Permanent Virtual Circuits (PVCs). The DLCI has only local significance and each end of the logical connection
assigns its own DLCI from the available local numbers.

Traffic Control based on Data Link Connection

Traffic Control as described in chapter 12 can also be performed on a Frame Relay interface for each permanent
virtual connection. The parameters in the

Add DLCI

menu are used in the same manner as those described in

chapter 12. More details are available in the CyROS Reference Guide.

STEP ONE
The first step is to set the general Frame Relay parameters, those applying to all DLCs. This is done in the Frame
Relay Menu. The parameters are shown in the table below. Most of these depend on the standards used by the
Frame Relay Network Provider.
The Local Management Interface (LMI) Protocol provides services not available in simple Frame Relay. It is used for
controlling the connection between the user and the network. It monitors this link, maintains the list of DLCs, and
sends status messages about the PVCs. A separate virtual circuit is created to pass this information (DLCI 0).
Frame Relay Menu CONFIG=>INTERFACE=><LINK>=>ENCAPSULATION =>FRAME RELAY

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