Cyclades PR1000 User Manual

Page 61

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Chapter 8 - Data-Link Protocols (Encapsulation)

Cyclades-PR1000

61

X.25 Menu (Continued)

Parameter

Description

Number of Virtual Circuits

Indicates the maximum number of virtual circuits (total of PVCs and SVCs)
allowed on this interface. The maximum is 128.

Number of Permanent
Virtual Circuits

Indicates the number of permanent virtual circuits that will be connected through
this interface. This maximum is also 128.

Layer 3 Window Size

The layer 3 (packet) level window represents the number of sequentially
numbered packets that can be sent before an acknowledgement must be
received. This number may be negotiated if the Window Size Facility is utilized
(see last parameter in this table).

Layer 2 Window Size

The layer 2 (frame) level window represents the number of sequentially
numbered frames that can be sent before an acknowledgement must be
received. The frame numbers are independent of the packet numbers.

Packet Size

The packet size to be sent across the interface. This number may be
negotiated if the Packet Size Facility is utilized (see last parameter in this table).

Number of Retries N2

Number of times an information frame can be resent, without response, before
the link is considered down.

TL

Time the frame level waits for an acknowledgement for a given frame before re-
sending it.

T2

Time that can elapse, after receiving a frame, until the router must send an
acknowledgement.

T21

Call Request response Timer. After this time has elapsed, the DTE sends a
Clear message.

T23

Clear Request response Timer. After this time has elapsed, the DTE
retransmits the Clear message.

Negotiable Facilities

Initiates facility negotiation during virtual circuit creation.

Send Facility

Determines which facilities are negotiated during virtual circuit creation:

Packet

size

is part of the flow control parameters negotiation,

Throughput

is part of the

throughput class negotiation, and

N3 Window

(Level 3 Window Size, above) is

part of the flow control parameters negotiation.

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