Cisco BPX 8650, Руководство по установке и настройке

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19-6
Cisco BPX 8600 Series Installation and Configuration
Release 9.3.30, Part Number 78-12907-01 Rev. E0, May 2005
Chapter 19 Configuring Circuit Lines and Ports
Local Management Interface and Integrated Local Management Interface
The LMI parameters are described in Table 19-3.
.
Early Abit Notification with Configurable Timer on LMI/ILMI Interface
The time required to reroute connections varies depending on different parameters, such as the number
of connections to reroute, reroute bundle size, and so on.
It is important to notify the customer premise equipment if a connection is derouted and fails to transport
user data after a specified time interval. However, it is also desirable not to send out Abit = 0, Abit =1
when a connection is derouted and rerouted quickly. Such notifications might prematurely trigger the
CPE backup facilities, causing instabilities in an otherwise stable system.
The Early Abit Notification on ILMI/LMI Using Configurable Timer feature allows Abit notifications to be
sent over the LMI/ILMI interface if a connection cannot be rerouted after a user-specified time. Abit = 0 is
not sent if the connection is rerouted successfully during that time.
The time period is configurable. The configurable time gives you the flexibility to synchronize the
operation of the primary network and backup utilities, such as dialed backup over the ISDN or PSTN
network.
Configuring Early Abit Notification
You configure the timer delay period by setting the cnfnodeparm parameters. You want to choose timer
settings that give you the flexibility to synchronize the operation of the primary network and backup
utilities, such as dialed backup over the ISDN or PSTN network.
Be aware of these guidelines when using the Early Abit feature:
•
When you enable this feature by using the cnfnodeparm command, you can specify that Abit
Notification be:
– sent either on deroute
–
or a user-configurable time after deroute
• This feature can also be turned off
•
It is recommended that this feature be set the same on all nodes. Otherwise, the Abit behavior can
be different on different nodes.
•
If this feature is turned off, switch software behaves the same as in previous releases. Existing
functionality continues to function in a mixed release network (releases 8.4, 8.5, or 9.1 IGX or BPX
network).
Table 19-3 LMI Parameters
Parameter Description
VPI.VCI VPI.VCI for LMI signaling channel equal 0.31
Polling Enable Keep-alive polling
T393 Status Enquiry timeout value
T394 Update Status timeout value
T396 Status Enquiry polling timer
N394 Status Enquiry retry count
N395 Update Status retry count