Table Of Contents
ATM PVC Bundle Enhancement — MPLS EXP-Based PVC Selection
VC Bundle Support and Bundle Management
Related Features and Technologies
Supported Standards, MIBs, and RFCs
Applying Parameters to Bundles
Configuring Bundle-Level Parameters
Configuring a VC Bundle Member Directly
Configuring VC Class Parameters to Apply to a Bundle
VC Bundle Configuration Using a VC Class Example
ATM PVC Bundle Enhancement — MPLS EXP-Based PVC Selection
Feature History
This document describes the ATM PVC Bundle Enhancement — MPLS EXP-Based PVC Selection feature in Cisco IOS Release 12.2(8)T. It includes the following sections:
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Supported Standards, MIBs, and RFCs
Feature Overview
The ATM PVC Bundle Enhancement — MPLS EXP-Based PVC Selection feature is an extension to the IP to ATM Class of Service feature suite. The IP to ATM Class of Service feature suite, using virtual circuit (VC) support and bundle management, maps quality of service (QoS) characteristics between IP and ATM. It provides customers who have multiple VCs (with varying qualities of service to the same destination) the ability to build a QoS differentiated network.
The IP to ATM Class of Service feature suite allowed customers to use IP precedence level as the selection criteria for packet forwarding. This new feature now gives customers the option of using the Multiprotocol Label Switching (MPLS) experimental (EXP) level as an additional selection criteria for packet forwarding.
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For more information about the IP to ATM Class of Service feature suite, refer to the "Configuring IP to ATM Class of Service" chapter of the Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.2.
VC Bundle Support and Bundle Management
ATM VC bundle management allows you to configure multiple VCs that have different QoS characteristics between any pair of ATM-connected routers. As shown in Figure 1, these VCs are grouped in a bundle and are referred to as bundle members.
Figure 1 ATM VC Bundle
ATM VC bundle management allows you to define an ATM VC bundle and add VCs to it. Each VC of a bundle has its own ATM traffic class and ATM traffic parameters. You can apply attributes and characteristics to discrete VC bundle members, or you can apply them collectively at the bundle level.
Using VC bundles, you can create differentiated service by flexibly distributing MPLS EXP levels over the different VC bundle members. You can map a single MPLS EXP level, or a range of these levels, to each discrete VC in the bundle, thereby enabling individual VCs in the bundle to carry packets marked with different MPLS EXP levels. You can use Weighted Random Early Detection (WRED) or distributed WRED (dWRED) to further differentiate service across traffic that has different MPLS EXP levels.
To determine which VC in the bundle to use to forward a packet to its destination, the ATM VC bundle management software matches MPLS EXP levels between packets and VCs (see Figure 2). IP traffic is sent to the next hop address for the bundle because all VCs in a bundle share the same destination, but the VC used to carry a packet depends on the value set for that packet in the MPLS EXP level of the type of service (ToS) byte of its header. The ATM VC bundle management software matches the MPLS EXP level of the packet to the MPLS EXP levels assigned to a VC, sending the packet out on the appropriate VC. Moreover, the ATM VC bundle management software allows you to configure how traffic will be redirected when the VC to which the packet was initially directed goes down. Figure 2 illustrates how the ATM VC bundle management software determines which permanent virtual circuit (PVC) bundle member to use to carry a packet and how WRED (or dWRED) is used to differentiate traffic on the same VC.
Figure 2 ATM VC Bundle PVC Selection for Packet Transfer
The support of multiple parallel ATM VCs allows you to create stronger service differentiation at the IP layer. For instance, you might want to configure the network to provide IP traffic belonging to real-time class of service (CoS) (such as Voice over IP traffic) on an ATM VC with strict constraints (constant bit rate (CBR) or variable bit rate real-time (VBR-rt), for example), while also allowing the network to transport nonreal-time traffic over a more elastic ATM unspecified bit rate (UBR) PVC. UBR is effectively the ATM version of best-effort service. Using a configuration such as this would allow you to make full use of your network capacity.
Benefits
Improved System Performance
This feature is designed to provide a true working solution to class-based services, without the investment of new ATM network infrastructures. Now networks can offer different service classes (sometimes termed differential service classes) across the entire WAN, not just the routed portion. Mission-critical applications can be given exceptional service during periods of high network usage and congestion. In addition, noncritical traffic can be restricted in its network usage, ensuring greater QoS for more important traffic and user types.
Additional Selection Criteria
This new feature now gives customers the option of using the MPLS EXP level, in addition to IP precedence, as a selection criteria for packet forwarding.
Restrictions
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Related Features and Technologies
This feature is similar to the IP to ATM Class of Service feature suite, which is documented in the "Configuring IP to ATM Class of Service" chapter of the Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.2.
Related Documents
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Supported Platforms
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The ATM Adapter PA-A3 is not supported on either the Cisco 3620 router or the Cisco 3640 router. Because certain QoS features (for example, WRED) require the ATM Adapter PA-A3, specific limitations may apply. For more information about platform and feature support, refer to Cisco Feature Navigator (described below).
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Determining Platform Support Through Cisco Feature Navigator
Cisco IOS software is packaged in feature sets that support specific platforms. To get updated information regarding platform support for this feature, access Cisco Feature Navigator. Cisco Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.
Cisco Feature Navigator is a web-based tool that enables you to quickly determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image. You can search by feature or release. Under the release section, you can compare releases side by side to display both the features unique to each software release and the features in common.
Cisco Feature Navigator is updated regularly when major Cisco IOS software releases and technology releases occur. For the most current information, go to the Cisco Feature Navigator home page at the following URL:
Supported Standards, MIBs, and RFCs
Standards
No new or modified standards are supported by this feature.
MIBs
No new or modified MIBs are supported by this feature.
To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:
http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml
RFCs
No new or modified RFCs are supported by this feature.
Configuration Tasks
See the following sections for configuration tasks for the ATM PVC Bundle Enhancement — MPLS EXP-Based PVC Selection feature. Each task in the list is identified as either required or optional.
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Enabling MPLS
To enable MPLS, use the following commands beginning in global configuration mode:
Creating a VC Bundle
To create a bundle and enter bundle configuration mode in which you can assign attributes and parameters to the bundle and to all of its member VCs, use the following command in interface configuration mode:
Router(config-if)# bundle bundle-name
Creates the specified bundle and enters bundle configuration mode.
Applying Parameters to Bundles
Parameters (or attributes) can be applied to bundles either by applying the parameters directly to the bundle or by applying the parameters to a VC class assigned to the bundle.
Applying parameters by using VC classes assigned to the bundle allows you to apply multiple parameters at once because you apply the VC class to the bundle and to all of its VC members. This method allows you to apply a parameter across all VCs for the bundle, after which (for some parameters) you can later modify that parameter for individual VCs. After configuring the parameters for the VC class, you need to attach the VC class to the bundle.
Parameters applied directly to a bundle take priority over those applied to VC classes assigned to the bundle. Parameters applied to VC classes assigned to the bundle take priority over those applied to individual VCs.
Note
To begin applying parameters to bundles, complete the procedure in the section "Configuring Bundle-Level Parameters."
Configuring Bundle-Level Parameters
To begin configuring parameters that apply to the bundle and to all of its members, use the following commands in bundle configuration mode, as needed:
What's Next?
Next, decide if you want to configure the VC bundle member directly or use a VC class attached to a bundle. To configure the VC bundle member directly, complete just the procedure in the "Configuring a VC Bundle Member Directly" section. To use a VC class attached to a bundle, instead complete the procedures in both the "Configuring VC Class Parameters to Apply to a Bundle" section and the "Attaching a Class to a Bundle" section.
Configuring a VC Bundle Member Directly
To configure an individual VC bundle member directly, use the following commands in bundle-vc configuration mode, as needed. To enter bundle-vc configuration mode, use the pvc-bundle command.
Configuring VC Class Parameters to Apply to a Bundle
To configure a VC class to contain commands that configure all VC members of a bundle when the class is applied to that bundle, use the following command in vc-class configuration mode. To enter vc-class configuration mode, use the vc-class atm command.
In addition to the oam-bundle command, you can add the following commands to a VC class to be used to configure a bundle: broadcast, encapsulation, inarp, oam retry, and protocol. For information on these commands, including configuration tasks and command syntax, refer to the Cisco IOS Wide-Area Networking Configuration Guide, Release 12.2 and the Cisco IOS Wide-Area Networking Command Reference, Release 12.2.
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Attaching a Class to a Bundle
To attach a VC class containing bundle-level configuration commands to a bundle, use the following command in bundle configuration mode. To enter bundle configuration mode, use the bundle command.
Router(config-if-atm-bundle)# class-bundle vc-class-name
Configures a bundle with the bundle-level commands contained in the specified VC class.
Verifying the Configuration
To verify the configuration of the feature, use the following commands in EXEC mode, as needed:
Configuration Examples
This section provides the following configuration example:
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VC Bundle Configuration Using a VC Class Example
This example configures VC bundle management on a router that uses Intermediate System-to-Intermediate System (IS-IS) as its IP routing protocol.
Bundle-Class Class
At the outset, this configuration defines a VC class called "bundle-class," which includes commands that set VC parameters. When the class bundle-class is applied at the bundle level, these parameters are applied to all VCs that belong to the bundle. Note that any commands applied directly to an individual VC of a bundle in bundle-vc mode take precedence over commands applied globally at the bundle level. Taking into account hierarchy precedence rules, VCs belonging to any bundle to which the class bundle-class is applied will be characterized by the following parameters: aal5snap encapsulation, broadcast on, use of Inverse ARP to resolve IP addresses, and OAM enabled.
router isisnet 49.0000.0000.0000.1111.00vc-class atm bundle-classencapsulation aal5snapbroadcastprotocol ip inarpoam-bundle manage 3oam 4 3 10The following four sections of the configuration define specific VC classes. Each of these classes contains commands used to specify parameters that can then be applied to individual VCs in a bundle by assigning the class to that VC.
Control-Class Class
When the class called "control-class" is applied to a VC, the VC carries traffic whose MPLS EXP level is 7. When the VC to which this class is assigned goes down, it takes the bundle down with it because this class makes the VC a protected one. The QoS type of a VC using this class is vbr-nrt.
vc-class atm control-classmpls experimental 7protect vcvbr-nrt 1000 5000 32Premium-Class Class
When the class called "premium-class" is applied to a VC, the VC carries traffic whose MPLS EXP levels are 6 and 5. The VC does not allow other traffic to be bumped onto it. When the VC to which this class is applied goes down, its bumped traffic will be redirected to a VC whose MPLS EXP level is 7. This class makes a VC a member of the protected group of the bundle. When all members of a protected group go down, the bundle goes down. The QoS type of a VC using this class is vbr-nrt.
vc-class atm premium-classmpls experimental 6-5no bump trafficprotect groupbump explicitly 7vbr-nrt 20000 10000 32Priority-Class Class
When the class called "priority-class" is applied to a VC, the VC is configured to carry traffic with an MPLS EXP level in the 4 - 2 range. The VC uses the implicit bumping rule, it allows traffic to be bumped, and it belongs to the protected group of the bundle. The QoS type of a VC using this class is ubr+.
vc-class atm priority-classmpls experimental 4-2protect groupubr+ 10000 3000Basic-Class Class
When the class called "basic-class" is applied to a VC, the VC is configured through the mpls experimental other command to carry traffic with MPLS EXP levels not specified in the profile. The VC using this class belongs to the protected group of the bundle. The QoS type of a VC using this class is ubr.
vc-class atm basic-classmpls experimental otherprotect groupubr 10000The following sets of commands configure three bundles that the router subinterface uses to connect to three of its neighbors. These bundles are called "new-york," "san-francisco," and "los-angeles." Bundle new-york has four VC members, bundle san-francisco has four VC members, and bundle los-angeles has three VC members.
new-york Bundle
The first part of this example specifies the IP address of the subinterface, the router protocol—the router uses IS-IS as an IP routing protocol—and it creates the first bundle called "new-york" and enters bundle configuration mode:
interface a1/0.1 multipointip address 10.0.0.1 255.255.255.0ip router isisbundle new-yorkFrom within bundle configuration mode, the next portion of the configuration uses two protocol commands to enable IP and Open Systems Interconnect (OSI) traffic flows in the bundle. The OSI routing packets will use the highest MPLS EXP VC in the bundle. The OSI data packets, if any, will use the lowest MPLS EXP VC in the bundle. If configured, other protocols, such as Internet Packet Exchange (IPX) or AppleTalk, will always use the lowest MPLS EXP VC in the bundle.
As the indentation levels of the preceding and following commands suggest, subordinate to bundle new-york is a command that configures its protocol and a command that applies the class called "bundle-class" to it.
protocol ip 1.1.1.2 broadcastprotocol clns 49.0000.0000.2222.00 broadcastclass-bundle bundle-classThe class called "bundle-class," which is applied to the bundle new-york, includes a protocol ip inarp command. According to inheritance rules, protocol ip, configured at the bundle level, takes precedence over protocol ip inarp specified in the class bundle-class.
The next set of commands beginning with pvc-bundle ny-control 207, which are further subordinate, add four VCs (called "ny-control," "ny-premium," "ny-priority," and "ny-basic") to the bundle new-york. A particular class—that is, one of the classes predefined in this configuration example—is applied to each VC to configure it with parameters specified by commands included in the class.
As is the case for this configuration, to configure individual VCs belonging to a bundle, the router must be in bundle mode for the mother bundle. For each VC belonging to the bundle, the subordinate mode is pvc-mode for the specific VC.
The following commands configure the individual VCs for the bundle new-york:
pvc-bundle ny-control 207class-vc control-classpvc-bundle ny-premium 206class-vc premium-classpvc-bundle ny-priority 204class-vc priority-classpvc-bundle ny-basic 201class-vc basic-classsan-francisco Bundle
The following set of commands create and configure a bundle called "san-francisco." At the bundle configuration level, the configuration commands included in the class bundle-class are ascribed to the bundle san-francisco and to the individual VCs that belong to the bundle. Then, the pvc-bundle command is executed for each individual VC to add it to the bundle. After a VC is added and bundle-vc configuration mode is entered, a particular, preconfigured class is assigned to the VC. The configuration commands comprising that class are used to configure the VC. Rules of hierarchy apply at this point. Command parameters contained in the applied class are superseded by the same parameters applied at the bundle configuration level, which are superseded by the same parameters applied directly to a VC.
bundle san-franciscoprotocol clns 49.0000.0000.0000.333.00 broadcastinarp 1class-bundle bundle-classpvc-bundle sf-control 307class-vc control-classpvc-bundle sf-premium 306class-vc premium-classpvc-bundle sf-priority 304class-vc priority-classpvc-bundle sf-basic 301class-vc basic-classlos-angeles Bundle
The following set of commands create and configure a bundle called "los-angeles." At the bundle configuration level, the configuration commands included in the class bundle-class are ascribed to the bundle los-angeles and to the individual VCs that belong to the bundle. Then, the pvc-bundle command is executed for each individual VC to add it to the bundle. After a VC is added and bundle-vc configuration mode is entered, the MPLS EXP level is set for the VC, and the VC is either configured as a member of a protected group (protect group) or as an individually protected VC. A particular class is then assigned to each VC to further characterize it. Rules of hierarchy apply. Parameters of commands applied directly and discretely to a VC take precedence over the same parameters applied within a class to the VC at the bundle-vc configuration level, which take precedence over the same parameters applied to the entire bundle at the bundle configuration level.
bundle los-angelesprotocol ip 1.1.1.4 broadcastprotocol clns 49.0000.0000.4444.00 broadcastinarp 1class-bundle bundle-classpvc-bundle la-high 407mpls experimental 7-5protect vcclass-vc premium-classpvc-bundle la-mid 404mpls experimental 4-2protect groupclass-vc priority-classpvc-bundle la-low 401mpls experimental otherprotect groupclass-vc basic-classCommand Reference
This section documents new and modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.2 command reference publications or new feature documentation. For more information, see the "Related Documents" section in this document.
New Commands
Modified Commands
mpls experimental
To configure Multiprotocol Label Switching (MPLS) experimental (EXP) levels for a virtual circuit (VC) class that can be assigned to a VC bundle and thus applied to all VC members of that bundle, use the mpls experimental command in vc-class configuration mode. To remove the MPLS EXP levels from the VC class, use the no form of this command.
To configure the MPLS EXP levels for a VC member of a bundle, use the mpls experimental command in bundle-vc configuration mode. To remove the MPLS EXP levels from the VC, use the no form of this command.
mpls experimental [other | range]
no mpls experimental
Syntax Description
Defaults
Defaults to other, that is, any MPLS EXP levels in the range from 0 to 7 that are not explicitly configured.
Command Modes
VC-class configuration (for a VC class)
Bundle-vc configuration (for ATM VC bundle members)
Command History
Usage Guidelines
Assignment of MPLS EXP levels to VC bundle members allows you to create differentiated service because you can distribute the MPLS EXP levels over the different VC bundle members. You can map a single level or a range of levels to each discrete VC in the bundle, thereby enabling VCs in the bundle to carry packets marked with different levels. Alternatively, you can configure a VC with the mpls experimental other command to indicate that it can carry traffic marked with levels not specifically configured for it. Only one VC in the bundle can be configured with the mpls experimental other command to carry all levels not specified. This VC is considered the default one.
To use this command in vc-class configuration mode, enter the vc-class atm global configuration command before you enter this command. This command has no effect if the VC class that contains the command is attached to a standalone VC, that is, if the VC is not a bundle member.
To use this command to configure an individual bundle member in bundle-vc configuration mode, first enter the bundle command to enact bundle configuration mode for the bundle to which you want to add or modify the VC member to be configured. Then, use the pvc-bundle command to specify the VC to be created or modified and enter bundle-vc configuration mode.
VCs in a VC bundle are subject to the following configuration inheritance guidelines (listed in order of next highest MPLS EXP level):
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Examples
The following example configures a class called "control-class" that includes a mpls experimental command that, when applied to a bundle, configures all VC members of that bundle to carry MPLS EXP level 7 traffic. Note, however, that VC members of that bundle can be individually configured with the mpls experimental command at the bundle-vc level, which would supervene.
vc-class atm control-classmpls experimental 7The following example configures permanent virtual circuit (PVC) 401 (with the name of control-class) to carry traffic with MPLS EXP levels in the range of 4 - 2, overriding the level mapping set for the VC through vc-class configuration:
pvc-bundle control-class 401mpls experimental 4-2Related Commands
show mpls forwarding-table
To display the contents of the MPLS Forwarding Information Base (FIB), use the show mpls forwarding-table command in EXEC mode.
show mpls forwarding-table [{network {mask | length} | labels label [- label] | interface interface | next-hop address | lsp-tunnel [tunnel-id]}] [detail]
Syntax Description
Command Modes
EXEC
Command History
Usage Guidelines
The optional parameters described allow specification of a subset of the entire FIB.
Examples
The following is sample output from the show mpls forwarding-table command:
Router# show mpls forwarding-tableLocal Outgoing Prefix Bytes tag Outgoing Next Hoptag tag or VC or Tunnel Id switched interface26 Untagged 10.253.0.0/16 0 Et4/0/0 172.27.32.428 1/33 10.15.0.0/16 0 AT0/0.1 point2point29 Pop tag 10.91.0.0/16 0 Hs5/0 point2point1/36 10.91.0.0/16 0 AT0/0.1 point2point30 32 10.250.0.97/32 0 Et4/0/2 10.92.0.732 10.250.0.97/32 0 Hs5/0 point2point34 26 10.77.0.0/24 0 Et4/0/2 10.92.0.726 10.77.0.0/24 0 Hs5/0 point2point35 Untagged [T] 10.100.100.101/32 0 Tu301 point2point36 Pop tag 168.1.0.0/16 0 Hs5/0 point2point1/37 168.1.0.0/16 0 AT0/0.1 point2point[T] Forwarding through a TSP tunnel.View additional tagging info with the 'detail' optionThe following is sample output from the show mpls forwarding-table command when you specify the detail keyword. If the MPLS EXP level is used as a selection criterion for packet forwarding, a Bundle adjacency exp (vcd) field is included in the display. This field includes the EXP value and the corresponding virtual circuit descriptor (VCD) in parentheses.
Router# show mpls forwarding-table detailLocal Outgoing Prefix Bytes tag Outgoing Next Hoptag tag or VC or Tunnel Id switched interface16 Pop tag 1.0.0.6/32 0 AT1/0.1 point2pointBundle adjacency exp(vcd)0(1) 1(1) 2(1) 3(1) 4(1) 5(1) 6(1) 7(1)MAC/Encaps=12/12, MTU=4474, Tag Stack{}00010000AAAA030000008847No output feature configured17 18 1.0.0.9/32 0 AT1/0.1 point2pointBundle adjacency exp(vcd)0(1) 1(1) 2(1) 3(1) 4(1) 5(1) 6(1) 7(1)MAC/Encaps=12/16, MTU=4470, Tag Stack{18}00010000AAAA030000008847 00012000No output feature configured18 19 1.0.0.10/32 0 AT1/0.1 point2pointBundle adjacency exp(vcd)0(1) 1(1) 2(1) 3(1) 4(1) 5(1) 6(1) 7(1)MAC/Encaps=12/16, MTU=4470, Tag Stack{19}00010000AAAA030000008847 00013000No output feature configured19 17 20.0.0.0/8 0 AT1/0.1 point2pointBundle adjacency exp(vcd)0(1) 1(1) 2(1) 3(1) 4(1) 5(1) 6(1) 7(1)MAC/Encaps=12/16, MTU=4470, Tag Stack{17}00010000AAAA030000008847 00011000No output feature configured20 20 60.0.0.0/8 0 AT1/0.1 point2pointBundle adjacency exp(vcd)0(1) 1(1) 2(1) 3(1) 4(1) 5(1) 6(1) 7(1)MAC/Encaps=12/16, MTU=4470, Tag Stack{20}00010000AAAA030000008847 00014000No output feature configured21 Pop tag 60.0.0.0/24 0 AT1/0.1 point2pointBundle adjacency exp(vcd)0(1) 1(1) 2(1) 3(1) 4(1) 5(1) 6(1) 7(1)MAC/Encaps=12/12, MTU=4474, Tag Stack{}00010000AAAA030000008847No output feature configured22 Pop tag 1.0.0.4/32 0 Et2/3 40.0.0.4MAC/Encaps=14/14, MTU=1504, Tag Stack{}000427AD10430005DDFE043B8847No output feature configuredTable 1 describes the significant fields shown in the output.
