Fault Tolerance; Nfas Limitations; Provisioning; Configuring Nfas - Lucent Technologies PortMaster 4 Configuration Manual

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NFAS message signaling travels over Ethernet using the User Datagram Protocol (UDP)

and UDP port 1650. A reliable, proprietary protocol provides packet sequencing,

acknowledgment for packets, and retransmission of lost packets.

Fault Tolerance

When you configure NFAS with D channel backup, you set one line as the primary

interface, one line as the secondary interface, and the remaining lines in the group as

slave interfaces. To increase the fault tolerance of the group, you can set the secondary

interface on a different Quad T1 board from the primary interface.

With the primary and secondary interfaces on separate boards, all calls in the group are

dropped when the primary interface board fails, but service resumes as soon as the

secondary interface assumes D channel signaling responsibilities. See "Configuring NFAS

with D Channel Backup" on page 10-17 for instructions on this type of fault-tolerant

configuration.

Each Quad T1 board can handle only one interface group and one type of signaling:

•

The four T1 interfaces on any Quad T1 line board cannot belong to different groups.

•

When you configure NFAS on one T1 interface, the other T1 interfaces cannot run

in standard PRI mode.

However, you can configure more than one Quad T1 board in the same group.

Because NFAS requires additional control command exchanges, NFAS T1 interfaces are

provisioned differently at the switch. To help you determine the kind of provisioning

you require for ISDN setup, refer to the information on the Lucent website at

http://www.livingston.com.

To configure NFAS on a T1 line, use the following command:

Command> set Line0 nfas primary|secondary|slave|disabled Identifier Group

See the PortMaster 4 Command Line Reference for syntax information.

This section describes how to configure NFAS with the D channel backup interface set,

for fault tolerance, on a different Quad T1 board from the primary interface. The

primary interface is set on Line0 in slot 0 for NFAS group 5. The secondary interface is

set on Line0 in slot 1. All other T1 interfaces on these two boards on the PortMaster 4

are set as slave interfaces for this group.

Configuring T1, E1, and ISDN PRI

Using NFAS for ISDN PRI

10-17

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