для Cisco Cisco IOS Software Releases 12.2 B
ISDN PRI-SLT
Information About ISDN PRI-SLT
2
Cisco IOS Release 12.2(8)B and Cisco IOS Release 12.2(15)T
Information About ISDN PRI-SLT
To configure the ISDN PRI-SLT feature, you need to understand the following concepts:
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ISDN Assumptions About the Location of the PRI D Channel
ISDN PRI is designed to carry large numbers of incoming ISDN calls at large central site locations.
ISDN PRI has 23 B channels running at 64 kbps each and a shared 64-kbps D channel that carries
signaling traffic. ISDN PRI is often referred to as “23 B + D” (North America and Japan) or “30 B + D”
(Europe and the rest of the world).
ISDN PRI has 23 B channels running at 64 kbps each and a shared 64-kbps D channel that carries
signaling traffic. ISDN PRI is often referred to as “23 B + D” (North America and Japan) or “30 B + D”
(Europe and the rest of the world).
shows how many B channels and D channels are assigned to the ISDN media types.
Figure 1
BRI and PRI Channel Assignments
shows the logical contents of a Cisco ISDN PRI interface used in a standard T1 network
configuration.
T1-PRI
23B + D
Used in North America
and Japan
Used in North America
and Japan
E1-PRI
30B + D
Used in Europe
Used in Europe
14051
B channel
D channel
B channel
D channel