Enterasys Networks CSX7000 Uživatelský manuál stáhnout pdf (Strana 250)

100

101

USER’S GUIDE

250 CyberSWITCH

X.25 RELIABILITY, WINDOWS, AND ACKNOWLEDGMENT

X.25 SEQUENCE NUMBER RANGE

The type of sequence numbers to be used for X.25; regular or extended. Extended sequence

numbering allows for packets to be assigned sequence numbers from 0-127 (modulo 128),

as opposed to 0-7 (modulo 8). The default value is modulo 8.

AXIMUM WINDOW SIZE

This is the largest possible window size to be supported on any virtual circuit. The window

size is the number of frames that a DTE can send without receiving an acknowledgment.

SVCs that support window size negotiation will never allow the agreed upon window size

to exceed this value. Using modulo 128, the DTEs can send up to 127 frames without

receiving an acknowledgment. Using modulo 8, the DTEs can send up to 7 frames without

receiving an acknowledgment. The default value for both modulo 8 and modulo 128 is 2.

AXIMUM PACKET SIZE

This value is used to determine the maximum packet size that the system will support for

X.25 connections. When packet size negotiation is performed on SVCs, this value will be

used as the upper bound. The default maximum packet size is 128 bytes.

X.25 Q

UALITY-OF-SERVICE FACILITIES

The X.25 Quality-of-Service Facilities apply only to SVCs. The first three configuration elements are

for SVCs that support negotiation.

AXIMUM THROUGHPUT CLASS

This value is used to determine the maximum throughput class that the system will

support for X.25 connections. Throughput describes the maximum amount of data that can

be sent through the network, when the network is operating at saturation. Factors

influencing throughput are line speeds, window sizes, and the number of active sessions

in the network. When throughput class negotiation is performed on SVCs, this value will

be used as the upper bound. The default value is 19,200 BPS.

LOW CONTROL NEGOTIATION

This configuration element specifies whether Flow Control Negotiation is to be supported

for SVCs (negotiation is not performed on PVCs). If Flow control negotiation is supported

for SVCs, the window and packet sizes can be negotiated between DTEs on a per-call basis.

As a default, this facility is not supported.

HROUGHPUT CLASS NEGOTIATION

This configuration element specifies whether Throughput Class Negotiation is to be

supported for SVCs (negotiation is not performed on PVCs). This facility allows the

throughput rates to be negotiated between DTEs on a per-call basis. As a default, this

facility is not supported.

Note: The next 6 items configured for the X.25 Quality of Service Facilities are the non-

standard default parameters for SVCs that do not support negotiation. These pa-

rameters are used on SVCs that do not use the standard X.25 values, but also do

not support any facility negotiation.

1 2 ... 245 246 247 248 249 250 251 252 253 254 255 ... 728 729

Komentáře k této Příručce

Žádné komentáře

Enterasys Networks CSX7000 Uživatelský manuál Strana 250

Komentáře k této Příručce