Avaya Configuring DLSw Services Bedienungsanleitung PDF herunterladen (Seite 68)

Configuring DLSw Services

2-12

304233-A Rev. 00

• LLC2 flow control

• TCP flow control

• DLSw RFC 1434 fixed and RFC 1795 adaptive pacing

LLC2 and TCP continue to assert flow control until congestion clears on a given

TCP connection.

The default settings for system parameters relevant to LLC2 and TCP flow control

are suitable for the majority of your DLSw service requirements.

LLC2 Flow Control

The LLC2 protocol interface provides a bidirectional window and a SAP credit

allocation, that together manage flow control on individual LLC2 connections

between the router and LAN-attached SNA or NetBIOS systems.

The SAP window attempts to limit the number of outstanding frames queued for

transmission to a remote endstation from a local endstation at this SAP address, as

follows:

1. As the local endstation sends frames that the remote endstation has yet to

acknowledge, a counter on the remote DLSw switch increments.

2. When this counter reaches half the value specified in the SAP Window

parameter, the remote DLSw switch sends a flow control indication back to

the local DLSw switch. This step is actually part of DLSw RFC 1434 fixed

flow control.

3. The local DLSw switch sends RNRs (receiver not ready) to the local

endstation to control the flow of the session.

4. As the remote endstation acknowledges frames, the counter on the remote

DLSw switch decrements.

5. After the remote endstation acknowledges all outstanding frames, the remote

DLSw switch sends an end-flow-control indication back to the local DLSw

switch.

6. The local DLSw switch then sends RR (receiver ready) to the local endstation,

thereby allowing it to send more frames.

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Avaya Configuring DLSw Services Bedienungsanleitung Seite 68