 Feedback
|
Table Of Contents
Preparing for Broadband Access Aggregation
Prerequisites for Preparing for Broadband Access Aggregation
Restrictions for Preparing for Broadband Access Aggregation
Information About Preparing for Broadband Access Aggregation
Virtual Access Interface Precloning
Configuration Enhancements for Broadband Scalability
Virtual Template Compatibility with Subinterfaces
Benefits of Using Broadband Scalability Features
How to Prepare for Broadband Access Aggregation
Benefits of Configuring a PVC Range
Configuring an ATM PVC or PVC Range
Configuring an Individual PVC Within a PVC Range
Configuring a Virtual Template
Precloning Virtual-Access Interfaces
Configuring Enhancements for Broadband Scalability
Verifying Virtual-Template Compatibility with Virtual-Access Subinterfaces
Disabling Virtual-Access Subinterfaces
Configuration Examples for Preparing for Broadband Access Aggregation
ATM PVC Range on a Point-to-Point Subinterface: Example
ATM PVC Range on a Multipoint Subinterface: Example
Individual PVC Within a PVC Range Configuration: Example
Virtual-Access Subinterfaces Configuration: Examples
Virtual-Access Subinterface Configuration: Example
Testing a Virtual Template for Compatibility with Subinterfaces: Example
Feature Information for Preparing for Broadband Access Aggregation
Preparing for Broadband Access Aggregation
First Published: May 2, 2005Last Updated: January 14, 2008Before you begin to perform the tasks required to accomplish broadband access aggregation, there are several preparatory tasks that you can perform at your option to enable you to complete the aggregation task with more efficiency. This module presents three of those preparation tasks: configuring permanent virtual circuits (PVCs), configuring a virtual template interface, and configuring enhancements for broadband scalability.
In a digital subscriber line (DSL) environment, many applications require the configuration of a large number of PVCs. Configuring PVCs before you start broadband aggregation can save you time because configuring a range of PVCs is faster than configuring PVCs individually.
A virtual template interface saves time because all PPP parameters are managed within the virtual template configuration. Any configurations made in the virtual template are automatically propagated to the individual virtual access interfaces.
Using the enhancement for broadband scalability reduces the amount of memory that is used per terminated PPP session by creating virtual access subinterfaces. Determining if virtual access subinterfaces are available on your system and preconfiguring these enhancements can speed your aggregation process and improve system performance.
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 Preparing for Broadband Access Aggregation" 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 Preparing for Broadband Access Aggregation
•
•
•
•
•
Prerequisites for Preparing for Broadband Access Aggregation
Before configuring broadband access aggregation, you will need to know the information that is presented in the "Understanding Broadband Access Aggregation" module.
Additional information can be found in these documents:
•
•
Restrictions for Preparing for Broadband Access Aggregation
Broadband scalability is not intended to improve the scalability of the following:
•
•
•
•
•
Information About Preparing for Broadband Access Aggregation
To prepare for broadband access aggregation, you should understand the following concepts:
•
Virtual-Access Interfaces
A virtual-template interface is used to provide the configuration for dynamically created virtual-access interfaces. It is created by users and can be saved in NVRAM.
Once the virtual-template interface is created, it can be configured in the same way as a serial interface.
Virtual-template interfaces can be created and applied by various applications such as virtual profiles, virtual private dialup networks (VPDN), PPP over ATM, protocol translation, and Multichassis Multilink PPP (MMP).
All PPP parameters are managed within the virtual-template configuration. Configuration changes made to the virtual template are automatically propagated to the individual virtual access interfaces. Multiple virtual-access interfaces can originate from a single virtual template; therefore, multiple PVCs can use a single virtual template.
Cisco IOS software supports up to 200 virtual-template configurations. If greater numbers of tailored configurations are required, an authentication, authorization, and accounting (AAA) server may be employed. Refer to the "Configuring Per-User Configuration" chapter in the Cisco IOS Dial Technologies Configuration Guide for additional information on configuring an AAA server.
If the parameters of the virtual template are not explicitly defined before the ATM PVC is configured, the PPP interface is brought up using default values from the virtual template. Some parameters (such as an IP address) take effect only if specified before the PPP interface comes up. Therefore, it is recommended that you explicitly create and configure the virtual template before configuring the ATM PVC to ensure that such parameters take effect. Alternatively, if parameters are specified after the ATM PVC has been configured, use the shutdown command followed by the no shutdown command on the ATM subinterface to restart the interface; this restart will cause the newly configured parameters (such as an IP address) to take effect.
Network addresses for the PPP-over-ATM connections are not configured on the main ATM interface or subinterface. Instead, they are configured on the appropriate virtual template or obtained via AAA.
The virtual templates support all standard PPP configuration commands; however, not all configurations are supported by the PPP-over-ATM virtual access interfaces. These restrictions are enforced at the time the virtual-template configuration is applied (cloned) to the virtual-access interface.
Autosense for ATM PVCs
The PPPoA/PPPoE Autosense for ATM PVCs feature enables a router to distinguish between incoming PPP over ATM (PPPoA) and PPP over Ethernet (PPPoE) over ATM sessions and to create virtual access based on demand for both PPP types.
Note
Virtual Access Interface Precloning
Precloning virtual-access interfaces for PPPoA at the NAS enables the virtual-access interface to be allocated at system start. This functionality significantly reduces the load on the system during call setup. When precloning is used, the virtual-access interface is attached to the session upon receipt of the first session-initiation packet from the client. The virtual-access interface is detached upon termination of the PPP session.
Configuration Enhancements for Broadband Scalability
The Configuration Enhancements for Broadband Scalability feature reduces the amount of memory that is used per terminated PPP session by creating virtual-access subinterfaces. Depending on the configuration of the source virtual template, virtual-access subinterfaces may be available. This feature also introduces a command to determine if a virtual template is compatible with virtual access subinterfaces.
Virtual Access Subinterfaces
The virtual-template command supports existing features, functions, and configurations. By default, the virtual-template subinterface command is enabled.
The virtual template manager will determine if the set of options configured on the virtual template are all supported on a subinterface. Virtual-access subinterfaces will be created for all virtual templates that support subinterfaces. If the user has entered any commands that are not supported on a subinterface, a full virtual access interface will be created and cloned for all PPP sessions using that virtual template. If the virtual-template subinterface command is disabled, full virtual-access interfaces will always be created.
Different applications can use the same virtual template even if one application is subinterface-capable and another is not. The virtual-template manager will be notified whether the application supports virtual-access subinterfaces and creates the appropriate resource.
The ppp multilink and ppp callback accept commands will not necessarily prevent subinterfaces from being created. Often, these commands are present in a virtual-template configuration, but PPP does not negotiate them. If neither of these features is negotiated, virtual-access subinterfaces will be created. If one or both of these features is negotiated, subinterfaces will not be created. The router will automatically determine if subinterfaces will be created depending on how PPP is negotiated on a case-by-case basis.
Virtual Template Compatibility with Subinterfaces
The test virtual-template subinterface privileged EXEC command determines whether a virtual template can support the creation of a virtual-access subinterface. If the virtual template contains commands that prevent the creation of subinterfaces, the test virtual-template subinterface command identifies and displays these commands.
If the creation of virtual-access subinterfaces is disabled by the no virtual-template subinterface command, the test virtual-template subinterface command produces no output.
The debug vtemplate subinterface command displays debug messages that are generated if you enter configuration commands on the virtual template that are not valid on a subinterface. These messages are generated only if the debug vtemplate subinterface command is enabled, the virtual-template subinterface command is enabled, and a virtual template is configured that can support the creation of subinterfaces. If the creation of virtual-access subinterfaces is disabled by the no virtual-template subinterface command, the debug vtemplate subinterface command produces no output.
Benefits of Using Broadband Scalability Features
Using broadband scalability reduces the amount of memory that is used per terminated PPP session by creating virtual-access subinterfaces. These virtual-access subinterfaces, along with improvements that are transparent to the user, speed up the cloning process.
How to Prepare for Broadband Access Aggregation
This section contains the following procedures:
•
•
Configuring PVCs
In a digital subscriber line (DSL) environment, many applications require the configuration of a large number of ATM PVCs.
Perform the following tasks to configure PVCs:
•
•
Benefits of Configuring a PVC Range
A PVC range saves time because configuring a range of PVCs is faster than configuring a number of PVCs individually.
Using a PVC range saves nonvolatile random access memory (NVRAM) because a range of PVCs takes up less NVRAM on network service routers than a large number of individually configured PVCs.
Using a PVC range speeds boot-up time because the command parser is able to parse one configuration command instead of many.
Configuring an ATM PVC or PVC Range
Perform the following task to configure an ATM PVC or PVC range.
SUMMARY STEPS
1.
2.
3.
or
interface atm number.subinterface-number [point-to-point | multipoint]
4.
or
range [range-name] pvc start-vpi/start-vci end-vpi/end-vci
5.
6.
DETAILED STEPS
Step 1
enable
Example:Router> enable
Enables privileged EXEC mode.
•
Step 2
configure terminal
Example:Router# configure terminal
Enters global configuration mode.
Step 3
interface atm slot/port.subinterface-number [point-to-point | multipoint]
or
interface atm number.subinterface-number [point-to-point | multipoint]
Example:Router(config)# interface atm 6/0.200 point-to-point
or
Router(config)# interface atm 1/0/0.4 multipoint
Specifies the ATM point-to-point or multipoint subinterface using the appropriate format of the
interface atm command.1Step 4
pvc [name] vpi/vci
or
range [range-name] pvc start-vpi/start-vci end-vpi/end-vci
Example:Router(config-subif)# pvc cisco 0/5
or
Router(config-subif)# range range1 pvc 1/200 1/299
Configures the PVC or a range of PVCs.
Step 5
exit
Example:Router(config-subif)# exit
(Optional) Exits the configuration session and returns to privileged EXEC mode.
Step 6
show atm pvc [vpi/vci | name | interface atm interface-number]
Example:Router(config)# show atm pvc 0/5
Displays all ATM permanent virtual connections (PVCs) and traffic information.
1 To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.
Example
The following is sample output from the show atm pvc command with the vpi/vci argument specified:
Router# show atm pvc 0/41ATM2/0: VCD: 3, VPI: 0, VCI: 41UBR, PeakRate: 155000AAL5-LLC/SNAP, etype:0x0, Flags: 0xC20, VCmode: 0x0OAM frequency: 0 second(s), OAM retry frequency: 1 second(s), OAM retry frequency: 1second(s)OAM up retry count: 3, OAM down retry count: 5OAM Loopback status: OAM DisabledOAM VC state: Not ManagedILMI VC state: Not ManagedInARP frequency: 15 minutes(s)InPkts: 31759, OutPkts: 26497, InBytes: 2356434, OutBytes: 1589743InPRoc: 15785, OutPRoc: 26472, Broadcasts: 0InFast: 20, OutFast: 20, InAS: 15954, OutAS: 6OAM cells received: 0F5 InEndloop: 0, F5 InSegloop: 0, F5 InAIS: 0, F5 InRDI: 0F4 InEndloop: 0, F4 InSegloop: 0, F4 InAIS: 0, F4 InRDI: 0OAM cells sent: 0F5 OutEndloop: 0, F5 OutSegloop: 0, F5 OutRDI: 0F4 OutEndloop: 0, F4 OutSegloop: 0, F4 OutRDI: 0OAM cell drops: 0Status: UPPPPOE enabled.Configuring an Individual PVC Within a PVC Range
Perform this task to configure an individual PVC within a range.
SUMMARY STEPS
1.
2.
3.
4.
5.
6.
7.
8.
DETAILED STEPS
Configuring a Virtual Template
Before configuring the ATM PVC for PPP over ATM, you typically create and configure a virtual template. Use the following commands to create and configure a virtual template.
SUMMARY STEPS
1.
2.
3.
4.
5.
6.
7.
DETAILED STEPS
Other optional configuration commands can be added to the virtual template configuration. For example, you can enable the PPP authentication on the virtual template using the ppp authentication chap command. Refer to the "Configuring Virtual Template Interfaces" chapter in the Cisco IOS Dial Technologies Configuration Guide for additional information about configuring the virtual template.
Precloning Virtual-Access Interfaces
Precloning virtual-access interfaces at the NAS reduces the load on the system during call setup. Use the following procedure to preclone a virtual-access interface.
SUMMARY STEPS
1.
2.
3.
4.
DETAILED STEPS
Example
In the following sample output, precloning is enabled for Virtual-Template 1, 250 virtual-access interfaces have been precloned, and 249 virtual-access interfaces are available for new PPPoA and PPPoE sessions. Only one virtual-access interface is in use, and no virtual-access interfaces were cloned during call setup.
Router# show vtemplateVirtual-Template 1, pre-cloning is onPre-clone limit: 250, current number: 249Active vaccess number: 1Generic free vaccess number: 0Configuring Enhancements for Broadband Scalability
To configure enhancement for broadband scalability, you will perform the following tasks:
•
•
Verifying Virtual-Template Compatibility with Virtual-Access Subinterfaces
Perform the following task to test a virtual template to determine if it is compatible with the creation of virtual access subinterfaces.
SUMMARY STEPS
1.
2.
DETAILED STEPS
Example
The output generated by the test virtual-template subinterface command describes the compatibility of the virtual template with the creation of subinterfaces.
This example shows output indicating that the virtual template is not compatible. This output also includes a list of the commands, which are configured on the virtual template, that cause the incompatibility.
Router# test virtual-template virtual-template1 subinterfaceSubinterfaces cannot be created usingVirtual-Template1Interface commands:traffic-shape rate 50000 8000 8000 1000Disabling Virtual-Access Subinterfaces
When a virtual template is not compatible with the creation of subinterfaces, use the following task to configure a router to always create full virtual-access interfaces instead of virtual-access subinterfaces.
Note
SUMMARY STEPS
1.
2.
3.
DETAILED STEPS
Configuration Examples for Preparing for Broadband Access Aggregation
This section provides the following configuration examples:
•
•
•
•
ATM PVC Range on a Point-to-Point Subinterface: Example
In the following example, a PVC range called "range1" is created with a total of 100 PVCs in the range. A point-to-point subinterface will be created for each PVC in the range. Routed bridge encapsulation is configured on this range.
interface atm 6/0.200 point-to-pointip unnumbered loopback 1atm route-bridged iprange range1 pvc 1/200 1/299endATM PVC Range on a Multipoint Subinterface: Example
In the following example, a PVC range called "range-pppoa-1" is created with a total of 500 PVCs in the range. PVC parameters are configured for the range, including the assignment of a VC class called "classA."
interface atm 6/0.110 multipointrange range-pppoa-1 pvc 100 4/199class-range classAubr 1000encapsulation aal5snapprotocol ppp virtual-template 2Individual PVC Within a PVC Range Configuration: Example
In the following example, "pvc1" within the PVC range called "range1" is deactivated.
interface atm 6/0.110 multipointrange range1 pvc 100 4/199class-range classApvc-in-range pvc1 3/104shutdownVirtual-Access Subinterfaces Configuration: Examples
This section provides the following configuration examples:
•
•
Virtual-Access Subinterface Configuration: Example
The example that follows shows a virtual template that is compatible with virtual-access subinterfaces.
Note
interface Virtual-Template1ip unnumbered Loopback0peer default ip address pool pool-1ppp authentication chapppp multilinkThe following example shows a configuration in which the creation of virtual-access subinterfaces has been disabled by the no virtual-access subinterface command. When this command is configured, virtual-access interfaces are not registered with the SNMP code on the router. In network environments that do not use SNMP to manage PPP sessions, this saves the memory and CPU processing that would be used to register the virtual-access interfaces with the SNMP code.
Current configuration :6003 bytes!! Last configuration change at 10:59:02 EDT Thu Sep 19 2004!version 12.2service timestamps debug datetime msecservice timestamps log datetime msecno service password-encryptionservice internalservice udp-small-serversservice tcp-small-servers!hostname ioswan5-lns!enable password lab!username cisco password 0 ciscoclock timezone EST -5clock summer-time EDT recurringaaa new-model!!aaa authentication ppp default localaaa authorization network default localaaa session-id commonip subnet-zerono ip gratuitous-arpsip cef!!no ip domain lookupip name-server 10.44.11.21ip name-server 10.44.11.206!ip vrf vpn1rd 10:1route-target export 10:1route-target import 10:1!vpdn enable!vpdn-group 1accept-dialinprotocol l2tpvirtual-template 1terminate-from hostname ioswan5-laclocal name tunnel1l2tp tunnel password 7 01100F175804!!
!no virtual-template subinterfaceno virtual-template snmpvirtual-template 1 pre-clone 10!!!buffers small permanent 20000buffers middle permanent 7500!!!interface Loopback1ip address 10.111.1.1 255.255.255.0Testing a Virtual Template for Compatibility with Subinterfaces: Example
This example shows the process for testing a virtual template to determine if it can support virtual-access subinterfaces. The following command displays the configuration for virtual template 1:
Router# show running interface virtual-template 1Building configuration...!interface Virtual-Template1ip unnumbered Loopback0peer default ip address pool pool-1ppp authentication chaptraffic-shape rate 50000 8000 8000 1000endThe test virtual-template subinterface command tests virtual template 1 to determine if it can support subinterfaces. The output shows that the traffic-shape rate command that is configured on virtual template 1 prevents the virtual template from being able to support subinterfaces.
Router# test virtual-template 1 subinterfaceSubinterfaces cannot be created using Virtual-Template1Interface commands:traffic-shape rate 50000 8000 8000 1000Where to Go Next
To configure broadband access, first select one of the three main configuration tasks:
1.
or
If you want to provide protocol support for PPP over ATM sessions, refer to the "Providing Protocol support for Broadband Access Aggregation of PPP over ATM Sessions" module. Then go to 2.
or
If you want to provide connectivity from a remote bridged ethernet network to a routed network using ATM routed bridge encapsulation, refer to the "Providing Connectivity Using ATM Routed Bridge Encapsulation" module.
2.
3.
–
–
–
–
–
–
–
–
Additional References
The following sections provide references related to the "Preparing for Broadband Aggregation" module.
Related Documents
Configuring a PVC range
"Configuring PVCs" chapter in the Cisco IOS Wide-Area Networking Configuration Guide
Broadband access aggregation concepts
"Understanding Broadband Access Aggregation" module of the Cisco IOS Broadband Access Aggregation and DSL Configuration Guide
Broadband access commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples
"Wide-Area Networking Commands" in the Cisco IOS Wide-Area Networking Command Reference, Release 12.3
Creating a virtual template
"Configuring Virtual Template Interfaces" chapter in the Cisco IOS Dial Technologies Configuration Guide
Standards
MIBs
None
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:
RFCs
Technical Assistance
Feature Information for Preparing for Broadband Access Aggregation
Table 4 lists the features in this module and provides links to specific configuration information.
Not all commands may be available in your Cisco IOS software release. For details on when support for specific commands was introduced, see the command reference documents.
If you are looking for information on a feature in this technology that is not documented here, see the "Configuring Broadband Access Aggregation Features Roadmap."
Cisco IOS software images are specific to a Cisco IOS software release, a feature set, and a platform. Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.
Table 4 Feature Information for Preparing for Broadband Aggregation
Configuration Enhancements for Broadband Scalability
12.2(13)T
12.2(15)B
12.2(33)SRCThis feature reduces the amount of memory that is used per terminated PPP session by creating virtual-access subinterfaces. Depending on the configuration of the source virtual template, virtual-access subinterface may be available. This feature also introduces a command to determine if a virtual template is compatible with virtual-access subinterfaces.
The following sections provide information about this feature:
•
PPPoA/PPPoE Autosense for ATM PVCs
12.2(4)T
12.2(4)T3This feature enables a router to distinguish between incoming PPP over ATM (PPPoA) and PPP over Ethernet (PPPoE) over ATM sessions and to create virtual access based on demand for both PPP types.
The following sections provide information about this feature:
•
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 used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.
© 2008 Cisco Systems, Inc. All rights reserved.
