AT&T Telephone DS1/DMi/ISDN-PRI Uživatelský manuál stáhnout pdf (Strana 148)

7-12

ADMINISTRATION OPTIONS AND REQUIREMENTS — SYSTEM 85

slip count of 44 or less and if the secondary and 50% of those DS1s that are enabled

for slip enable have reached their maximum slip count of 88, then a switch back to

the primary is made.

Field 11

V1-V4

Offers the options external loop not available (0) or external loop available (1).

The external loop available option should only be selected when demand diagnostic

maintenance is done and then only after a DS1 has been busied out. If DS1 is a

primary or secondary reference, the reference should be switched off line. This

option is used with procedure 620, test 2, to extend the range of the test to include

the network channel-terminating equipment (NCTE) and the connecting facility.

The external loop available option should only be used for the duration of the test.

Field 12

V1-V4

Specifies whether (1) or not (0) the associated T1-span is used as an incoming

synchronization source to the switch.

The network synchronization diagram should show those transmission facilities that

are used for synchronization. Each switch permits a maximum of two interfaces

(one primary and one secondary) to be translated (1) in field 12. However, there is

no requirement to have both.

Field 13

V1-V4

Selects whether a DS1 facility (translated in field 12) is to be used as the primary or

secondary synchronization source to the switch. Field encodes and their descriptions

are:

The facility is not used as a synchronization source

The facility is the primary synchronization source

The facility is the secondary synchronization source

NOTE: The primary must be administered before the secondary. The

secondary must be removed before the primary.

Only slots translated (1) and (2) must be configured with synchronization cables.

These cables connect the backplane of the translated ANN11_/ANN35 to the

backplane of the TN463. The cables are identified as group 334 for intercabinet and

group 361 for intracabinet applications.

CAUTION: A loop-timing problem can be created if the synchronization

sources are not administered correctly. The loop-timing problem exists as the

result of an error where both switch endpoints (for the same T1-span) are

administered as the primary. This causes the clock frequency to vary widely and

result in bringing down the switch. Loop-timing problems can be avoided by

following a correctly engineered network synchronization diagram.

1 2 ... 143 144 145 146 147 148 149 150 151 152 153 ... 395 396

Žádné komentáře

AT&T Telephone DS1/DMi/ISDN-PRI Uživatelský manuál Strana 148