Table Of Contents
Frame Relay PVC Bundles with QoS Support for IP and MPLS
Prerequisites for Frame Relay PVC Bundles with QoS Support for IP and MPLS
Restrictions for Frame Relay PVC Bundles with QoS Support for IP and MPLS
Information About Frame Relay PVC Bundles with QoS Support for IP and MPLS
Benefits of Frame Relay PVC Bundles with QoS Support for IP and MPLS
Frame Relay PVC Bundle Support
Service Levels and PVC Selection Criteria
Frame Relay PVC Bundle Management
How to Configure Frame Relay PVC Bundles with QoS Support for IP and MPLS
Configuring Frame Relay PVC Bundles with IP QoS Support
Configuring Frame Relay PVC Bundles with MPLS QoS Support
Verifying Frame Relay PVC Bundles Configuration
Monitoring and Maintaining Frame Relay PVC Bundles
Configuration Examples for Frame Relay PVC Bundles with QoS Support for IP and MPLS
PVC Bundles with IP QoS Support on Main, Multipoint, and Point-to-Point Interfaces Example
PVC Bundle with IP QoS Support with Multiple QoS Parameters Example
PVC Bundle with MPLS QoS Support Example
Verifying Frame Relay PVC Bundle Configuration Examples
Monitoring and Maintaining Frame Relay PVC Bundles Examples
bump (Frame Relay VC-bundle-member)
dscp (Frame Relay VC-bundle-member)
encapsulation (Frame Relay VC-bundle)
inarp (Frame Relay VC-bundle-member)
precedence (Frame Relay VC-bundle-member)
protect (Frame Relay VC-bundle-member)
show frame-relay ip rtp header-compression
show frame-relay ip tcp header-compression
Frame Relay PVC Bundles with QoS Support for IP and MPLS
First Published: November 25, 2002Last Updated: February 28, 2006Frame Relay permanent virtual circuit (PVC) bundle functionality allows you to associate a group of Frame Relay PVCs with a single next-hop address. When Frame Relay PVC bundles are used with IP, packets are mapped to specific PVCs in the bundle on the basis of the precedence value or differentiated services code point (DSCP) settings in the type of service (ToS) field of the IP header. Each packet is treated differently according to the QoS configured for each PVC.
MPLS QoS support for Frame Relay PVC bundles extends Frame Relay PVC bundle functionality to support the mapping of Multiprotocol Label Switching (MPLS) packets to specific PVCs in the bundle. MPLS packets are mapped to PVCs according to the settings of the experimental (EXP) bits in the MPLS packet header.
History for the Frame Relay PVC Bundles with QoS Support for IP and MPLS Feature
Release Modification12.2(13)T
This feature was introduced.
12.2(28)SB
This feature was integrated into Cisco IOS Release 12.2(28)SB.
Finding Support Information for Platforms and Cisco IOS Software Images
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Contents
•
Prerequisites for Frame Relay PVC Bundles with QoS Support for IP and MPLS
•
Restrictions for Frame Relay PVC Bundles with QoS Support for IP and MPLS
•
Information About Frame Relay PVC Bundles with QoS Support for IP and MPLS
•
How to Configure Frame Relay PVC Bundles with QoS Support for IP and MPLS
•
Configuration Examples for Frame Relay PVC Bundles with QoS Support for IP and MPLS
Prerequisites for Frame Relay PVC Bundles with QoS Support for IP and MPLS
To implement Frame Relay PVC bundles between two routers, you must enable IP Cisco Express Forwarding switching on the routers.
To configure MPLS EXP levels on bundle member PVCs, you must have tag-switching enabled on the interface.
It is recommended (but not required) that you implement PVC Interface Priority Queueing (PIPQ) in conjunction with Frame Relay PVC bundles. This will ensure that if the interface becomes congested, higher-priority traffic can exit the interface ahead of lower-priority traffic.
Restrictions for Frame Relay PVC Bundles with QoS Support for IP and MPLS
•
A PVC can be a part of one and only one PVC bundle.
•
A PVC bundle may contain no more than eight PVCs.
•
A PVC that is a bundle member cannot be used in any other capacity, For example a PVC bundle member cannot be configured in a map statement.
•
A PVC bundle cannot perform precedence and DSCP matching at the same time. If the wrong matching scheme is configured, unpredictable behavior will result.
•
A PVC bundle will not come up unless all the precedence, DSCP, or EXP levels are configured in the bundle.
•
Voice over Frame Relay (VoFR) is not supported on PVC-bundle members.
•
Fast switching over Frame Relay PVC bundles is not supported.
Information About Frame Relay PVC Bundles with QoS Support for IP and MPLS
Before configuring and implementing Frame Relay PVC Bundles with QoS Support for IP and MPLS, you should understand the following concepts:
•
Benefits of Frame Relay PVC Bundles with QoS Support for IP and MPLS
•
Frame Relay PVC Bundle Support
•
Frame Relay PVC Bundle Management
Benefits of Frame Relay PVC Bundles with QoS Support for IP and MPLS
•
IP or MPLS packets carrying different types of traffic can be transported on different PVCs within the same PVC bundle.
•
Precedence-based PVC bundles can be converted to EXP-based PVC bundles by enabling tag-switching. EXP-based PVC bundles can be converted to precedence-based PVC bundles by disabling tag-switching.
•
This feature provides flexible PVC management within a PVC bundle by allowing traffic assigned to a failed PVC to be redirected to an alternate PVC within the bundle. This feature also allows you to configure the bundle to go down when certain PVCs go down.
Frame Relay PVC Bundle Support
The use of Frame Relay PVC bundles allows you to configure multiple PVCs with different QoS characteristics between any pair of Frame Relay-connected routers. As shown in Figure 1, a PVC bundle may contain up to eight PVCs. The individual PVCs within a bundle are called bundle members.
To determine which PVC in a bundle will be used to forward a specific type of traffic, the router maps the IP precedence level or DSCP value in an IPv4 packet header to a PVC configured with the same value. In the case of MPLS, packets are mapped to specific PVCs in a bundle based on the settings of the EXP bits in the MPLS packet headers.
Once you define a Frame Relay bundle and add PVCs to it, you can configure attributes and characteristics to discrete PVC bundle members, or you can apply them collectively at the bundle level. Frame Relay traffic shaping may be applied to every PVC within a bundle. As with individual PVCs, you can enable rate adaptation to occur in response to incoming backward explicit congestion notifications (BECN) from the network.
Figure 1 Frame Relay PVC bundle
You can create differentiated service using PVC bundles by distributing IP precedence levels or DSCP values over the various bundle members. You can map either a single precedence level or a range of precedence levels to each PVC in the bundle. Thus, either you can limit an individual PVC to carry only packets marked with a specific precedence level or you can enable a PVC to carry packets marked with different precedence levels.
Service Levels and PVC Selection Criteria
The DSCP and Precedence bits classify IP packet service levels. The Precedence field consists of the first three bits of the ToS octet in the IPv4 header. These bits define eight precedence levels. When DSCP mapping is used, the DSCP octet replaces the ToS octet in the IPv4 header. Currently the first six bits are used, defining 64 service levels.
Using precedence-based or DSCP-based mapping, each IPv4 packet is mapped to a specific PVC in the bundle, according to the value of the ToS or DSCP octet in the IP header. There is no special treatment for broadcast or multicast or IP routing packets; the only differentiation in treatment is a result of the ToS or DSCP octet settings.
The MPLS EXP bits make up a three-bit experimental field in the MPLS packet header. They are a bit-by-bit copy of the IP Precedence bits and provide the same eight QoS levels. Under MPLS EXP-based mapping, each MPLS packet is mapped to a specific PVC in the bundle, according the setting of the EXP bits.
Frame Relay PVC Bundle Management
In addition to mapping specific traffic types to specific PVCs according to QoS parameters designated by the ToS or DSCP values in the IPv4 headers or EXP values in the MPLS headers, PVC bundle management takes care of handling non-IP traffic and determining what happens if a PVC goes down.
By default, Inverse Address Resolution Protocol (ARP) traffic and other critical non-IP traffic is carried by the PVC configured for carrying IP Precedence or EXP level 6 or DSCP level 63. You can select a PVC with a different QoS to carry Inverse ARP traffic if required. Noncritical non-IP traffic is carried by the PVC that configured for carrying IP precedence, EXP, or DSCP level 0.
It is important during configuration to account for every precedence, EXP, or DSCP level in the configuration of the PVC bundle members. If all the packet service levels are not accounted for, the PVC bundle will never come up.
Once a PVC bundle is up, if an individual bundle member goes down, an attempt is made to identify an alternate PVC to handle the packet service level or levels that were carried by the downed PVC. If no alternate PVC is found, the entire PVC bundle is brought down.
Traffic Bumping
You can configure each PVC bundle member to bump traffic to another PVC in the bundle in the event that the bundle member goes down. You can specify whether the bumping will be implicit or explicit bumping. You can also specify that a particular PVC will never accept bumped traffic from another PVC. The default conditions are to perform implicit traffic bumping and to accept bumped traffic.
Implicit bumping diverts the traffic from a failed PVC to the PVC having the next-lower service level. Explicit bumping forces the traffic to a specific PVC rather than allowing it to find a PVC carrying traffic of the next-lower service level. For example, PVC x, responsible for carrying precedence level 3 traffic, can be configured to bump its traffic to PVC y, responsible for carrying precedence level 6 traffic—provided that PVC y is configured to accept bumped traffic. If PVC x goes down, PVC y takes over. If PVC y is already down or goes down later, the alternate PVC selected will depend on the bumping rule for PVC y. If no alternate PVC can be found for bumped traffic, the entire PVC bundle goes down.
PVC-Bundle Protection Rules
Traffic bumping provides a way to keep a PVC bundle up and traffic flowing even though some individual PVCs may be down. Protection rules provide a way to force the PVC bundle down even though some individual PVCs are up and might be able to handle all the traffic, though perhaps not in a satisfactory manner.
You can configure a PVC bundle member as an individually protected PVC or as part of a PVC bundle protected group. Only one protected group may exist within a PVC bundle; however, many individually protected PVCs may exist. The protection rules add flexibility for controlling the PVC bundle state.
When any one individually protected PVC goes down, the entire bundle goes down. If all the PVCs in a protected group go down, the entire bundle goes down.
If no protection rule is specified, the PVC bundle goes down only when all the PVCs go down. However, protection is overridden if a PVC that has no place to bump its traffic goes down. In this case, the entire bundle will go down despite any protection rules that have been set up.
MPLS EXP-based Mapping
To enable MPLS EXP-based mapping, tag-switching must be enabled on the interface or subinterface by using the tag-switching ip command. When tag-switching is enabled, MPLS and IP packets can flow across the interface and PVC bundles that are configured for IP Precedence mapping are converted to MPLS EXP mapping. The PVC bundle functionality remains the same with respect to priority levels, bumping, and so on, but the match precedence command is replaced by match exp, and each precedence command is replaced by the exp command. The effect is that a bundle member PVC previously configured to carry precedence level 1 IP traffic now carries EXP level 1 MPLS traffic.
PVC bundles configured for DSCP mapping go down when tag-switching is enabled. The DSCP configuration for each bundle member PVC is reset, resulting in the PVCs being unmapped and Inverse ARP, bumping, and protection settings being unconfigured. The match dscp command is replaced by match exp command.
When tag-switching is disabled, the match precedence and match dscp commands are restored and the exp commands are replaced by precedence commands.
When tag-switching is enabled or disabled, PVC bundles configured for IP precedence mapping or MPLS EXP mapping will stay up and traffic will transmit over the appropriate bundle member PVCs.
How to Configure Frame Relay PVC Bundles with QoS Support for IP and MPLS
This section contains the following configuration tasks.
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Configuring Frame Relay PVC Bundles with IP QoS Support (required)
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Configuring Frame Relay PVC Bundles with MPLS QoS Support (required)
•
Verifying Frame Relay PVC Bundles Configuration (optional)
•
Monitoring and Maintaining Frame Relay PVC Bundles (optional)
Configuring Frame Relay PVC Bundles with IP QoS Support
To configure Frame Relay PVC bundles for handling IP packets, perform the following steps:
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
ip routing
4.
ip cef
5.
interface type number
or
interface type number.subinterface-number [multipoint | point-to-point]6.
encapsulation frame-relay [cisco | ietf]
7.
ip address ip-address mask [secondary]
8.
frame-relay map protocol protocol-address {dlci | vc-bundle vc-bundle-name} [broadcast] [ietf | cisco]
9.
frame-relay vc-bundle vc-bundle-name
10.
encapsulation [ cisco| ietf]
11.
match {dscp dscp-value | precedence precedence-value}
12.
pvc dlci [vc-name]
13.
class name
14.
precedence {level | other}
or
dscp {level | other}15.
bump {explicit level | implicit | traffic}
16.
protect {group | vc}
17.
inarp
18.
end
19.
Configure the PVC bundle on the peer router.
DETAILED STEPS
Configuring Frame Relay PVC Bundles with MPLS QoS Support
To configure Frame Relay PVC bundles for handling MPLS packets, perform the following steps:
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
ip routing
4.
ip cef
5.
interface type number
or
interface {type slot | port-adapter | port.subinterface-number}[multipoint | point-to-point]
6.
encapsulation frame-relay [cisco | ietf]
7.
tag-switching ip
8.
ip address ip-address mask [secondary]
9.
frame-relay map protocol protocol-address {dlci | vc-bundle vc-bundle-name} [broadcast] [ietf | cisco]
10.
frame-relay vc-bundle vc-bundle-name
11.
encapsulation [ietf | cisco]
12.
pvc dlci [vc-name]
13.
class name
14.
exp {level | other}
15.
bump {explicit level | implicit | traffic}
16.
protect {group | vc}
17.
inarp
18.
end
19.
Configure the PVC bundle on the peer router.
DETAILED STEPS
Verifying Frame Relay PVC Bundles Configuration
To verify the configuration and operation of Frame Relay PVC bundles with QoS support, perform the following optional steps:
SUMMARY STEPS
1.
enable
2.
show frame-relay vc-bundle vc-bundle-name [detail]
3.
show frame-relay map
4.
show frame-relay pvc
5.
show frame-relay ip rtp header-compression [interface type number]
6.
show frame-relay ip tcp header-compression [interface type number]
7.
show adjacency [type number] [detail] [summary]
DETAILED STEPS
Monitoring and Maintaining Frame Relay PVC Bundles
To monitor and maintain Frame Relay PVC bundles, perform this task.
SUMMARY STEPS
1.
enable
2.
debug frame-relay adjacency {pvc [dlci] | vc-bundle [vc-bundle-name]}
3.
debug frame-relay vc-bundle {detail | state-change} [vc-bundle-name]
DETAILED STEPS
Configuration Examples for Frame Relay PVC Bundles with QoS Support for IP and MPLS
This section provides the following configuration examples:
•
PVC Bundles with IP QoS Support on Main, Multipoint, and Point-to-Point Interfaces Example
•
PVC Bundle with IP QoS Support with Multiple QoS Parameters Example
•
PVC Bundle with MPLS QoS Support Example
•
Verifying Frame Relay PVC Bundle Configuration Examples
•
Monitoring and Maintaining Frame Relay PVC Bundles Examples
PVC Bundles with IP QoS Support on Main, Multipoint, and Point-to-Point Interfaces Example
The following example shows the configuration of five PVC bundles with IP precedence and DSCP mapping. Two bundles are configured on the main interface, one bundle with static mapping and one with dynamic mapping. Two bundles are configured on a multipoint subinterface, one bundle with static mapping and one with dynamic mapping. One bundle is configured on a point-to-point subinterface.
configure terminalip routingip cefinterface Serial 1/4encapsulation frame-relayframe-relay intf-type dteip address 10.1.1.1 255.0.0.0frame-relay map ip 192.168.2.2 vc-bundle MAIN-1-staticframe-relay vc-bundle MAIN-1-staticmatch precedencepvc 100 1aprecedence otherpvc 101 1bprecedence 1pvc 102 1cprecedence 2pvc 103 1dprecedence 3pvc 104 1eprecedence 4pvc 105 1fprecedence 5pvc 106 1gprecedence 6pvc 107 1hframe-relay vc-bundle MAIN-2-dynamicmatch precedencepvc 200precedence 0pvc 201precedence 1pvc 202precedence 2pvc 203precedence 3pvc 204precedence 4pvc 205precedence 5pvc 206precedence 6pvc 207precedence 7interface Serial 1/4.1 multipointip address 172.16.1.1 255.0.0.0frame-relay map ip 172.17.2.2 vc-bundle MP-3-staticframe-relay vc-bundle MP-3-staticmatch precedencepvc 300 3aprecedence 0pvc 301 3bprecedence 1pvc 302 3cprecedence 2pvc 303 3dprecedence 3pvc 304 3eprecedence 4pvc 305 3fprecedence 5pvc 306 3gprecedence 6pvc 307 3hprecedence 7interface Serial 1/4.1 multipointframe-relay vc-bundle MP-4-dynamicmatch precedencematch dscppvc 400 4adscp otherpvc 401 4bdscp 10-19pvc 402 4cdscp 20-29pvc 403 4ddscp 30-39pvc 404 4edscp 40-49pvc 405 4fdscp 50-59pvc 406 4gdscp 60-62pvc 407 4hdscp 63endinterface Serial 1/4.2 point-to-pointip address 192.168.2.1 255.0.0.0frame-relay vc-bundle P2P-5match precedencepvc 500 5aprecedence 0pvc 501 5bprecedence 1pvc 502 5cprecedence 2pvc 503 5dprecedence 3pvc 504 5eprecedence 4pvc 505 5fprecedence 5pvc 506 5gprecedence 6pvc 507 5hprecedence 7PVC Bundle with IP QoS Support with Multiple QoS Parameters Example
The following example shows the configuration of a Frame Relay PVC bundle with DSCP-based mapping. The bundle member PVCs are configured with bumping, protection, and other parameters.
interface Serial 1/4.2 point-to-pointframe-relay vc-bundle BUNDLE-SEFENencapsulation ietfmatch dscppvc 301dscp otherbump explicit 45protect groupclass CIR-64000pvc 302dscp 40-49bump explicit 20no bump trafficprotect vcinarppvc 303dscp 30-39bump implicitprotect groupPVC Bundle with MPLS QoS Support Example
The following example shows the configuration of four Frame Relay PVC bundle members with MPLS EXP level support in the PVC bundle named "user1".
interface serial 0.1 point-to-pointencapsulation frame-relayip address 10.1.1.1tag-switching ipframe-relay vc-bundle user1pvc 100 ny-controlclass controlexp 7protect vcpvc 101 ny-premiumclass premiumexp 6-5bump explicit 7no bump trafficprotect grouppvc 102 my-priorityclass priorityexp 4-2protect grouppvc 103 ny-basicclass basicexp otherprotect group
Verifying Frame Relay PVC Bundle Configuration Examples
The following examples show output for the commands that can be used to verify Frame Relay PVC bundle configuration.
Sample Output for the show frame-relay vc-bundle Command
The following example shows the Frame Relay PVC bundle named "MP-4-dynamic" with PVC protection applied. Note that in this PVC bundle, DLCI 400 is configured to bump traffic explicitly to the PVC that handles DSCP level 40, which is DLCI 404. All the other DLCIs are configured for implicit bumping. In addition, all the DLCIs are configured to accept bumped traffic.
The asterisk (*) before PVC 4a indicates that this PVC was configured with the precedence other command, which means the PVC will handle all levels that are not explicitly configured on other PVCs.
In this example all PVCs are up so the values in the "Active level" fields match the values in the "Config level" fields. If a PVC goes down and its traffic is bumped, the "Active level" field value for the PVC that went down is cleared. The "Active level" field values for the PVC that the traffic bumped to will be updated to include the levels of the PVC that went down.
The first three PVCs in the following example make up a protected group. All three of these PVCs must go down before the bundle will go down. The last two PVCs are protected PVCs: if either of these PVCs go down, the bundle will go down.
Router# show frame-relay vc-bundle MP-4-dynamicMP-4-dynamic on Serial 1/4.1 - Status: UP Match-type: DSCPName DLCI Config. Active Bumping PG/ CIR Statuslevel level to/accept PV kbps*4a 400 0-9 0-9 40/Yes pg up4b 401 10-19 10-19 9/Yes pg up4c 402 20-29 20-29 19/Yes pg up4d 403 30-39 30-39 29/Yes - up4e 404 40-49 40-49 39/Yes - up4f 405 50-59 50-59 49/Yes - up4g 406 60-62 60-62 59/Yes pv up4h 407 63 63 62/Yes pv upPackets sent out on vc-bundle MP-4-dynamic : 0:Router#The following example shows the detail output of a PVC bundle. Note in this example that because all packet service levels are not handled, and because the PVCs are currently down, this bundle can never come up.
Router# show frame-relay vc-bundle x41 detailx41 on Serial1/1 - Status: DOWN Match-type: DSCPName DLCI Config. Active Bumping PG/ CIR Statuslevel level to/accept PV kbps410 50-62 49/Yes - down411 30,32,34,36,3.. 29/Yes - downPackets sent out on vc-bundle x41 : 0Active configuration and statistics for each member PVCDLCI Output pkts Active level410 0 50-62411 0 30,32,34,36,38-40Router#Sample Output for the show frame-relay map Command
The following sample output displays map and connection information for a PVC bundle called "MAIN-1-static":
Router# show frame-relay mapSerial1/4 (up):ip 10.2.2.2 vc-bundle MAIN-1-static, static,CISCO, status upSample Output for the show frame-relay pvc Command
The following sample output indicates that PVC 202 is a member of VC bundle "MAIN-1-static":
Router# show frame-relay pvc 202PVC Statistics for interface Serial1/4 (Frame Relay DTE)DLCI = 202, DLCI USAGE = LOCAL, PVC STATUS = STATIC, INTERFACE = Serial1/4input pkts 0 output pkts 45 in bytes 0out bytes 45000 dropped pkts 0 in FECN pkts 0in BECN pkts 0 out FECN pkts 0 out BECN pkts 0in DE pkts 0 out DE pkts 0out bcast pkts 0 out bcast bytes 05 minute input rate 0 bits/sec, 0 packets/sec5 minute output rate 2000 bits/sec, 2 packets/secpvc create time 00:01:25, last time pvc status changed 00:01:11VC-Bundle MAIN-1-staticSample Output for the show adjacency Command
The following is sample output for the show adjacency command for a PVC bundle configured on serial subinterface 1/4.1. Each bundle member is listed. The bundle itself is indicated by "incomplete" because no traffic actually transmitted on that entry.
Router# show adjacencyProtocol Interface AddressIP Serial1/4.1 10.2.2.2(4)IP Serial1/4.1 10.2.2.2(4)IP Serial1/4.1 10.2.2.2(4)IP Serial1/4.1 10.2.2.2(

