Agilent Technologies auroraSonata, Руководство пользователя

Страница: 131 / 336

Issue 2 - 07/00 4-21
Testing in Simulation Mode - Section 2
Checking the status of Layers 2 and 3
Layer 2 of the OSI 7-layer model is the Data Link layer. It
performs the Link Access Procedure on the D channel
(LAPD).
The Layer 3 (Network Layer) protocol provides the means to
establish, maintain and terminate network connections (ISDN
calls).
Tip
You will find more information about the OSI 7-layer model
in the
Glossary and the Introduction to ISDN .
In Simulation mode, the status of Layers 2 and 3 is indicated
by vertical arrows on the Status bar. For example:
Notes
• Layer 1 must be active before Layers 2 and 3 can
operate.
• If Layer 2 is not active, then Layer 3 cannot operate,
since Layer 2 passes Layer 3 information along the line.
If Layers 2 and 3 are not active
If Layers 2 and 3 are not active, check that aurora
Sonata
is set up
correctly for the link—the protocol is correct, the tester is
configured to test the appropriate type of link, B TEI
allocation is set up as required and so on.