Zhone Technologies Network Device Switch, Bi-directional Default Routing, Alternate Routing

Zhone Technologies, Inc. IMACS Product Book, Version 4

Bi-directional Default Routing

Bi-directional Default Routing is provided for automatic routing when a node is configured with two Primary Rate D channels as shown in Figure 29. In two channel systems, the user does not have to configure any routing information, as all calls received on one D channel are automatically routed to the second D channel. The user only needs to enter routing information for those calls destined to a local HSU or FXS ports.

HSU/FXS

D ch 1

IMACS

ISDN

Switch

D ch 2

PBX

Default

Figure 29—Bi-Directional Default Routing

Alternate Routing

Alternate routing is provided for calls to take an alternate path in the event of a congested or failed primary trunk. When there are more than two Primary Rate D channels, phone numbers can be assigned to more than one D channel. Calls placed or routed through the PRI server will now have an alternate route if no bandwidth is available on the first specified path. Alternate routing will also take place in the event of a failure of the first Primary Rate circuit. In the example shown in Figure 30, the call from D1 is usually routed to D2, as the D channel numbering is more specific. However, if the D2 trunk become congested or go out of service, the call will be routed to D3.

ISDN

Switch

Dial 415 - 6xxx

D1

PBX

IMACS

415-6xxx

D2

ISDN

D3Switch

415-xxxx

Figure 30—Alternate Routing

March 2001 Page 78