Table Of Contents
ISDN BCAC and Round-Robin Channel Selection Enhancements
Finding Feature Information
Contents
Prerequisites for ISDN BCAC and Round-Robin Channel Selection Enhancements
Information About ISDN BCAC and Round-Robin Channel Selection Enhancements
BCAC Enhancements
Round-Robin Selection Scheme for ISDN B Channels
Logging of ISDN Events
Additional ISDN Switch Types Supported for Network Emulation
How to Configure the ISDN BCAC and Round-Robin Channel Selection Enhancements
Configuring BCAC Service Audit Triggers
Configuring BCAC Service State Triggers
Configuring BCAC Message Retransmission
Configuring B-Channel Selection Order
Configuring ISDN Syslog Messages
Configuration Examples for ISDN BCAC and Round-Robin Channel Selection Enhancements
Example: Configuring BCAC Service Audit Triggers
Example: Configuring BCAC Service State Triggers
Example: Configuring BCAC Message Retransmission
Example: Configuring B-Channel Selection Order
Example: Configuring ISDN Syslog Messages
Additional References
Related Documents
Standards
MIBs
RFCs
Technical Assistance
Feature Information for ISDN BCAC and Round-Robin Channel Selection Enhancements
Glossary
ISDN BCAC and Round-Robin Channel Selection Enhancements
First Published: May 20, 2003
Last Updated: April 12, 2011
The ISDN BCAC and Round-Robin Channel Selection Enhancements feature allows more dynamic control of the ISDN B channels by providing the additional B-Channel Availability Control (BCAC) functionality for configuring message signaling and an enhanced channel selection scheme that adds a round-robin configuration to the existing ascending and descending channel selection schemes already available.
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the "Feature Information for ISDN BCAC and Round-Robin Channel Selection Enhancements" section.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Contents
•Prerequisites for ISDN BCAC and Round-Robin Channel Selection Enhancements
•Information About ISDN BCAC and Round-Robin Channel Selection Enhancements
•How to Configure the ISDN BCAC and Round-Robin Channel Selection Enhancements
•Configuration Examples for ISDN BCAC and Round-Robin Channel Selection Enhancements
•Additional References
•Feature Information for ISDN BCAC and Round-Robin Channel Selection Enhancements
•Glossary
Prerequisites for ISDN BCAC and Round-Robin Channel Selection Enhancements
You need to be familiar with the BCAC service message signaling procedure and the procedure for configuring ISDN PRI before configuring the commands described in this document. See the "Standards" section for a list of references.
Information About ISDN BCAC and Round-Robin Channel Selection Enhancements
•BCAC Enhancements
•Round-Robin Selection Scheme for ISDN B Channels
•Logging of ISDN Events
•Additional ISDN Switch Types Supported for Network Emulation
BCAC Enhancements
BCAC is a service message signaling procedure used to control the availability of ISDN B channels. BCAC provides a coordinated capability between both ends of a PRI to simultaneously preclude selection of specified B channels for outgoing calls, and reject calls (if channel negotiation is employed, calls may go on another channel) for those same channels. The basic BCAC functionality for the handling of SERV and SERV ACK messages already exists on Cisco routers. In Cisco IOS Release 12.3(1), the software has been enhanced with the following BCAC functionality:
•Provides improved processing of SERV and SERV ACK messages. Even though these messages are already handled in the Cisco IOS software, their processing has been enhanced to more closely align with the behavior described in the standards.
•Provides a mechanism to allow the retransmission of SERV messages.
•Handles SERV message collision cases.
•Provides service status audits for various audit triggers.
•Provides an option, that when set, triggers the exchange of service messages on all channels of the interface when the router is rebooted and when the signaling link comes up.
•Provides a mechanism so that if there is a flood of service messages that need to be sent, the service messages can be throttled to avoid losing them.
•Initializes the B-channel service status upon provisioning.
Round-Robin Selection Scheme for ISDN B Channels
ISDN enhancements introduced in Cisco IOS Release 12.3(1) enable you to select a B channel on a PRI or a nonfacility associated signaling (NFAS) interface in a round-robin fashion. This option is in addition to the ascending or descending channel selection schemes already available.
Logging of ISDN Events
ISDN enhancements introduced in Cisco IOS Release 12.3(1) support syslog logging of the following ISDN events:
•ISDN Layer 2 Up and Down events at severity 3.
•ISDN SERV, SERV ACK, Restart, Restart Ack, and Status Enq messages at severity 4.
•ISDN SERV status audit messages for various triggers at different severities.
Additional ISDN Switch Types Supported for Network Emulation
ISDN enhancements introduced in Cisco IOS Release 12.3(1) extend network emulation capability to the Lucent 4ESS, 5ESS, and Nortel DMS-100 ISDN switch types. These switch types can be configured as network, but not all network-side features are supported.
How to Configure the ISDN BCAC and Round-Robin Channel Selection Enhancements
•Configuring BCAC Service Audit Triggers (optional)
•Configuring BCAC Service State Triggers (optional)
•Configuring BCAC Message Retransmission (optional)
•Configuring B-Channel Selection Order (optional)
•Configuring ISDN Syslog Messages (optional)
Configuring BCAC Service Audit Triggers
Perform this task to configure BCAC service audit triggers.
SUMMARY STEPS
1. enable
2. configure terminal
3. interface serial port:channel
4. isdn bcac service audit
5. isdn bcac service audit trigger number
6. isdn bcac service audit interface
7. end
DETAILED STEPS
|
Command or Action
|
Purpose
|
Step 1
|
enable
Example:
Router> enable
|
Enables privileged EXEC mode.
•Enter your password if prompted.
|
Step 2
|
configure terminal
Example:
Router# configure terminal
|
Enters global configuration mode.
|
Step 3
|
interface serial port:channel
Example:
Router(config)# interface serial 2:23
|
Enters interface configuration mode on the specified serial port and channel.
|
Step 4
|
isdn bcac service audit
Example:
Router(config-if)# isdn bcac service audit
|
Enables BCAC service audits.
|
Step 5
|
isdn bcac service audit trigger number
Example:
Router(config-if)# isdn bcac service audit
trigger 2
|
Enables individual BCAC service audit triggers.
|
Step 6
|
isdn bcac service audit interface
Example:
Router(config-if)# isdn bcac service audit
interface
|
Specifies that BCAC service audits must be triggered on the entire interface.
|
Step 7
|
end
Example:
Router(config-if)# end
|
Exits interface configuration mode and returns to privileged EXEC mode.
|
Configuring BCAC Service State Triggers
Perform this task to configure BCAC service state triggers.
SUMMARY STEPS
1. enable
2. configure terminal
3. interface serial port:channel
4. isdn bcac service update provision
5. isdn bcac service update linkup
6. end
DETAILED STEPS
|
Command or Action
|
Purpose
|
Step 1
|
enable
Example:
Router> enable
|
Enables privileged EXEC mode.
•Enter your password if prompted.
|
Step 2
|
configure terminal
Example:
Router# configure terminal
|
Enters global configuration mode.
|
Step 3
|
interface serial port:channel
Example:
Router(config)# interface serial 2:23
|
Enters interface configuration mode on the specified serial port and channel.
|
Step 4
|
isdn bcac service update provision
Example:
Router(config-if)# isdn bcac service update
provision
|
Enables the BCAC service status functionality for provisioning the B channels.
|
Step 5
|
isdn bcac service update linkup
Example:
Router(config-if)# isdn bcac service update
linkup
|
Triggers updates of the BCAC service states between peer nodes through exchange of SERV and SERV ACK messages.
|
Step 6
|
end
Example:
Router(config-if)# end
|
Exits interface configuration mode and returns to privileged EXEC mode.
|
Configuring BCAC Message Retransmission
Perform this task to configure retransmission of BCAC service messages.
SUMMARY STEPS
1. enable
2. configure terminal
3. interface serial port:channel
4. isdn bcac service timer timer-value
5. isdn bcac service retry max retries
6. isdn bcac service retry in-serv-on-fail
7. end
DETAILED STEPS
|
Command or Action
|
Purpose
|
Step 1
|
enable
Example:
Router> enable
|
Enables privileged EXEC mode.
•Enter your password if prompted.
|
Step 2
|
configure terminal
Example:
Router# configure terminal
|
Enters global configuration mode.
|
Step 3
|
interface serial port:channel
Example:
Router(config)# interface serial 2:23
|
Enters interface configuration mode on the specified serial port and channel.
|
Step 4
|
isdn bcac service timer timer-value
Example:
Router(config-if)# isdn bcac service timer 600
|
Changes the value of the BCAC T3M1 or T323 service message timer.
•Valid range is from 500 to 120000 ms, and the default is 120000 ms.
|
Step 5
|
isdn bcac service retry max retries
Example:
Router(config-if)# isdn bcac service retry max
retries 5
|
Specifies the maximum number of times that a BCAC service message can be retransmitted when unacknowledged.
•The default is 2 attempts, and you can enter a number from 0 to 127.
|
Step 6
|
isdn bcac service retry in-serv-on-fail
Example:
Router(config-if)# isdn bcac service retry
in-serv-on-fail
|
Specifies that the BCAC service state of the channel needs to be changed to In-Service, because no acknowledgment message was received.
|
Step 7
|
end
Example:
Router(config-if)# end
|
Exits interface configuration mode and returns to privileged EXEC mode.
|
Configuring B-Channel Selection Order
Perform this task to configure selection order of the ISDN B channels.
SUMMARY STEPS
1. enable
2. configure terminal
3. interface serial port:channel
4. isdn bchan-number-order {ascending | descending} [round-robin]
5. end
DETAILED STEPS
|
Command or Action
|
Purpose
|
Step 1
|
enable
Example:
Router> enable
|
Enables privileged EXEC mode.
•Enter your password if prompted.
|
Step 2
|
configure terminal
Example:
Router# configure terminal
|
Enters global configuration mode.
|
Step 3
|
interface serial port:channel
Example:
Router(config)# interface serial 2:23
|
Enters interface configuration mode on the specified serial port and channel.
|
Step 4
|
isdn bchan-number-order
{ascending | descending} [round-robin]
Example:
Router(config-if)# isdn bchan-number-order
ascending round-robin
|
Configures an ISDN PRI interface to make outgoing call selection in ascending or descending order.
•The optional round-robin keyword adds the round-robin selection functionality to the selection order.
|
Step 5
|
end
Example:
Router(config-if)# end
|
Exits interface configuration mode and returns to privileged EXEC mode.
|
Configuring ISDN Syslog Messages
Perform this task to configure logging of ISDN syslog messages.
SUMMARY STEPS
1. enable
2. configure terminal
3. isdn logging
4. end
DETAILED STEPS
|
Command or Action
|
Purpose
|
Step 1
|
enable
Example:
Router> enable
|
Enables privileged EXEC mode.
•Enter your password if prompted.
|
Step 2
|
configure terminal
Example:
Router# configure terminal
|
Enters global configuration mode.
|
Step 3
|
isdn logging
Example:
Router(config)# isdn logging
|
Enables logging of ISDN syslog messages.
|
Step 4
|
end
Example:
Router(config)# end
|
Exits global configuration mode and returns to privileged EXEC mode.
|
Configuration Examples for ISDN BCAC and Round-Robin Channel Selection Enhancements
•Example: Configuring BCAC Service Audit Triggers
•Example: Configuring BCAC Service State Triggers
•Example: Configuring BCAC Message Retransmission
•Example: Configuring B-Channel Selection Order
•Example: Configuring ISDN Syslog Messages
Example: Configuring BCAC Service Audit Triggers
The following example shows how to enable service audits on serial interface 4:23:
The following example shows how to disable service trigger 4 on serial interface 4:23:
no isdn bcac service audit trigger 4
See the command page for the isdn bcac service audit trigger command for a list of triggers that can be disabled.
The following example shows how to configure service audits on the entire interface:
isdn bcac service audit interface
Example: Configuring BCAC Service State Triggers
The following example shows how to enable the SERV status message for provisioning the B channels on serial interface 4:23:
isdn bcac service update provision
The following example shows how to trigger service state updates on serial interface 4:23:
isdn bcac service update linkup
Example: Configuring BCAC Message Retransmission
The following example shows how to configure an option whereby, on service message exchange failure, the service state of the concerned channel or channels will be set to In-Service:
isdn bcac service retry in-serv-on-fail
The following example shows how to set the maximum number of service message retransmissions on serial interface 2:23 to 50:
isdn bcac service retry max 50
The following example shows how to change the service timers to 600 ms on serial interface 2:23:
isdn bcac service timer 600
Example: Configuring B-Channel Selection Order
The following example configures the outgoing B channel selection order on a PRI interface to be round-robin in ascending order:
interface serial 5:10
isdn bchan-number-order ascending round-robin
Example: Configuring ISDN Syslog Messages
The following example shows how to configure ISDN syslog logging:
Additional References
Related Documents
Standards
Standard
|
Title
|
AT&T PRI
|
Technical Report 41459—AT&T ISDN Primary Rate Interface and Special Application Specification; "User Network Interface Description," 1999.
|
National ISDN Council (NIC) PRI
|
SR (Special Report)—NWT-002343—ISDN Primary Rate Interface Generic Guidelines for Customer Premises Equipment, June 1993.
SR-3887—National ISDN Primary Rate Interface Customer Premises Equipment Generic Guidelines, 1996.
|
Nortel PRI
|
NIS (Network Interface Specification)—A211-1—DMS100 ISDN Primary Rate Network User Interface, 1993.
|
MIBs
MIB
|
MIBs Link
|
None
|
To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:
http://www.cisco.com/go/mibs
|
RFCs
Technical Assistance
Description
|
Link
|
The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.
|
http://www.cisco.com/cisco/web/support/index.html
|
Feature Information for ISDN BCAC and Round-Robin Channel Selection Enhancements
Table 1 lists the release history for this feature.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Note Table 1 lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Table 1 Feature Information for ISDN BCAC and Round-Robin Channel Selection Enhancements
Feature Name
|
Releases
|
Feature Information
|
ISDN BCAC and Round-Robin Channel Selection Enhancements
|
12.3(1)
|
The ISDN BCAC and Round-Robin Channel Selection Enhancements feature allows more dynamic control of the ISDN B channels by providing the additional B-Channel Availability Control (BCAC) functionality for configuring message signaling and an enhanced channel selection scheme that adds round-robin configuration to the existing ascending and descending channel selection schemes already available.
The following commands were introduced or modified: isdn bcac service audit, isdn bcac service audit interface, isdn bcac service audit trigger, isdn bcac service retry in-serv-on-fail, isdn bcac service retry max, isdn bcac service timer, isdn bcac service update linkup, isdn bcac service update provision, isdn bchan-number-order, isdn logging, isdn protocol-emulate (dial).
|
Glossary
PBX—private branch exchange.
RESTART—restart message.
RESTART ACK—restart acknowledge message.
SERV—service message.
SERV ACK—service acknowledge message.
STATUS ENQ—status enquiry message.
Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1005R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.
© 2003- 2011 Cisco Systems, Inc. All rights reserved.