MPLS TE-Tunnel-Based Admission Control

Last Updated: July 04, 2011

The MPLS TE--Tunnel-Based Admission Control (TBAC) feature enables classic Resource Reservation Protocol (RSVP) unicast reservations that are traveling across a Multiprotocol Label Switching Traffic Engineering (MPLS TE) core to be aggregated over an MPLS TE tunnel.

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 Table at the end of this document.

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Prerequisites for MPLS TE-Tunnel-Based Admission Control

  • You must configure an MPLS TE tunnel in the network.
  • You must configure RSVP on one or more interfaces on at least two neighboring routers that share a link within the network.

Restrictions for MPLS TE-Tunnel-Based Admission Control

  • Only IPv4 unicast RSVP flows are supported.
  • Primary, one-hop tunnels are not supported. The TE tunnel cannot be a member of a class-based tunnel selection (CBTS) bundle.
  • Multi-Topology Routing (MTR) is not supported.
  • Only preestablished aggregates are supported. They can be configured statically or dynamically using command-line interface (CLI) commands.
  • This feature is supported on Cisco 7600 series routers only.

Information About MPLS TE-Tunnel-Based Admission Control

Feature Overview of MPLS TE-Tunnel-Based Admission Control

TBAC aggregates reservations from multiple, classic RSVP sessions over different forms of tunneling technologies that include MPLS TE tunnels, which act as aggregate reservations in the core. The figure below gives an overview of TBAC.

Figure 1 TBAC Overview


The figure above shows three RSVP end-to-end (E2E) flows that originate at routers on the far left, and terminate on routers at the far right. These flows are classic RSVP unicast flows, meaning that RSVP is maintaining a state for each flow. There is nothing special about these flows, except that along their path, these flows encounter an MPLS-TE core, where there is a desire to avoid creating a per-flow RSVP state.

When the E2E flows reach the edge of the MPLS-TE core, they are aggregated onto a TE tunnel. This means that when transiting through the MPLS-TE core, their state is represented by a single state; the TE tunnel is within the aggregation region, and their packets are forwarded (label-switched) by the TE tunnel. For example, if 100 E2E flows traverse the same aggregator and deaggregator, rather than creating 100 RSVP states (PATH and RESV messages) within the aggregation region, a single RSVP-TE state is created, that of the aggregate, which is the TE tunnel, to allocate and maintain the resources used by the 100 E2E flows. In particular, the bandwidth consumed by E2E flows within the core is allocated and maintained in aggregate by the TE tunnel. The bandwidth of each E2E flow is normally admitted into the TE tunnel at the headend, just as any E2E flow’s bandwidth is admitted onto an outbound link in the absence of aggregation.

Benefits of MPLS TE-Tunnel-Based Admission Control

To understand the benefits of TBAC, you should be familiar with how Call Admission Control (CAC) works for RSVP and QoS.

Cost Effective

Real-time traffic is very sensitive to loss and delay. CAC avoids QoS degradation for real-time traffic because CAC ensures that the accepted load always matches the current network capacity. As a result, you do not have to overprovision the network to compensate for absolute worst peak traffic or for reduced capacity in case of failure.

Improved Accuracy

CAC uses RSVP signaling, which follows the exact same path as the real-time flow, and routers make a CAC decision at every hop. This ensures that the CAC decision is very accurate and dynamically adjusts to the current conditions such as a reroute or an additional link. Also, RSVP provides an explicit CAC response (admitted or rejected) to the application, so that the application can react appropriately and fast; for example, sending a busy signal for a voice call, rerouting the voice call on an alternate VoIP route, or displaying a message for video on demand.

RSVP and MPLS TE Combined

TBAC allows you to combine the benefits of RSVP with those of MPLS TE. Specifically, you can use MPLS TE inside the network to ensure that the transported traffic can take advantage of Fast Reroute protection (50-millisecond restoration), Constraint Based Routing (CBR), and aggregate bandwidth reservation.

Seamless Deployment

TBAC allows you to deploy IPv4 RSVP without any impact on the MPLS part of the network because IPv4 RSVP is effectively tunneled inside MPLS TE tunnels that operate unchanged as per regular RSVP TE. No upgrade or additional protocol is needed in the MPLS core.

Enhanced Scaling Capability

TBAC aggregates multiple IPv4 RSVP reservations ingressing from the same MPLS TE headend router into a single MPLS TE tunnel and egressing from the same MPLS TE tailend router.

How to Configure MPLS TE-Tunnel-Based Admission Control

Enabling RSVP QoS

Perform this task to enable RSVP QoS globally on a router.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ip rsvp qos

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
ip rsvp qos


Example:

Router(config)# ip rsvp qos

 

Enables RSVP QoS globally on a router.

 
Step 4
end


Example:

Router(config)# end

 

(Optional) Returns to privileged EXEC mode.

 

Enabling MPLS TE

Perform this task to enable MPLS TE globally on a router that is running RSVP QoS.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    mpls traffic-eng tunnels

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
mpls traffic-eng tunnels


Example:

Router(config)# mpls traffic-eng tunnels

 

Enables MPLS TE globally on a router.

 
Step 4
end


Example:

Router(config)# end

 

(Optional) Returns to privileged EXEC mode.

 

Configuring an MPLS TE Tunnel Interface

Perform this task to configure MPLS-TE tunneling on an interface.

Before You Begin

You must configure an MPLS-TE tunnel in your network before you can proceed. For detailed information, see the "MPLS Traffic Engineering (TE)--Automatic Bandwidth Adjustment for TE Tunnels" module.


SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface tunnel number

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
interface tunnel number


Example:

Router(config)# interface tunnel1

 

Specifies a tunnel interface and enters interface configuration mode.

 
Step 4
end


Example:

Router(config-if)# end

 

(Optional) Returns to privileged EXEC mode.

 

Configuring RSVP Bandwidth on an MPLS TE Tunnel Interface

Perform this task to configure RSVP bandwidth on the MPLS TE tunnel interface that you are using for the aggregation.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface tunnel number

4.    ip rsvp bandwidth [interface-kbps] [single-flow-kbps]

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 tunnel number


Example:

Router(config)# interface tunnel1

 

Specifies a tunnel interface and enters interface configuration mode.

 
Step 4
ip rsvp bandwidth [interface-kbps] [single-flow-kbps]

Example:

Router(config-if)# ip rsvp bandwidth 7500

 

Enables RSVP bandwidth on an interface.

  • The optional interface-kbps and single-flow-kbps arguments specify the amount of bandwidth that can be allocated by RSVP flows or to a single flow, respectively. Values are from 1 to 10000000.
Note    You must enter a value for the interface-kbpsargument on a tunnel interface.
 
Step 5
end


Example:

Router(config-if)# end

 

(Optional) Returns to privileged EXEC mode.

 

Verifying the TBAC Configuration


Note
You can use the following show commands in user EXEC or privileged EXEC mode.
SUMMARY STEPS

1.    enable

2.    show ip rsvp [atm-peak-rate-limit| counters| host| installed| interface| listeners| neighbor| policy| precedence| request| reservation| sbm| sender| signalling| tos]

3.    show ip rsvp reservation [detail] [filter[destination ip-address | hostname] [dst-port port-number] [source ip-address | hostname][src-port port-number]]

4.    show ip rsvp sender [detail] [filter[destination ip-address | hostname] [dst-port port-number] [source ip-address | hostname][src-port port-number]]

5.    show mpls traffic-eng link-management bandwidth-allocation [interface-name | summary [interface-name]]

6.    exit


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Router> enable

 

(Optional) Enables privileged EXEC mode.

  • Enter your password if prompted.
Note    Skip this step if you are using the show commands in user EXEC mode.
 
Step 2
show ip rsvp [atm-peak-rate-limit| counters| host| installed| interface| listeners| neighbor| policy| precedence| request| reservation| sbm| sender| signalling| tos]


Example:

Router# show ip rsvp

 

Displays specific information for RSVP categories.

  • The optional keywords display additional information.
 
Step 3
show ip rsvp reservation [detail] [filter[destination ip-address | hostname] [dst-port port-number] [source ip-address | hostname][src-port port-number]]


Example:

Router# show ip rsvp reservation detail

 

Displays RSVP-related receiver information currently in the database.

  • The optional keywords display additional information.
Note    The optional filter keyword is supported in Cisco IOS Releases 12.0S and 12.2S only.
 
Step 4
show ip rsvp sender [detail] [filter[destination ip-address | hostname] [dst-port port-number] [source ip-address | hostname][src-port port-number]]


Example:

Router# show ip rsvp sender detail

 

Displays RSVP PATH-related sender information currently in the database.

  • The optional keywords display additional information.
Note    The optional filter keyword is supported in Cisco IOS Releases 12.0S and 12.2S only.
 
Step 5
show mpls traffic-eng link-management bandwidth-allocation [interface-name | summary [interface-name]]


Example:

Router# show mpls traffic-eng link-management bandwidth-allocation

 

Displays current local link information.

  • The optional keywords display additional information.
 
Step 6
exit


Example:

Router# exit

 

(Optional) Exits privileged EXEC mode and returns to user EXEC mode.

 

Configuration Examples for MPLS TE-Tunnel-Based Admission Control

Example Configuring TBAC


Note
You must have an MPLS TE tunnel already configured in your network. For detailed information, see the "MPLS Traffic Engineering (TE)--Automatic Bandwidth Adjustment for TE Tunnels" module.

The following example enables RSVP and MPLS TE globally on a router and then configures a tunnel interface and bandwidth of 7500 kbps on the tunnel interface traversed by the RSVP flows: 

Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# ip rsvp qos
Router(config)# mpls traffic-eng tunnels
Router(config)# interface tunnel1
Router(config-if)# ip rsvp bandwidth 7500
Router(config-if)# end

Example Configuring RSVP Local Policy on a Tunnel Interface

The following example configures an RSVP default local policy on a tunnel interface:

Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# interface tunnel1
Router(config-if)# ip rsvp policy local default
Router(config-rsvp-local-if-policy)# max bandwidth single 10
Router(config-rsvp-local-if-policy)# forward all
Router(config-rsvp-local-if-policy)# end

Example Verifying the TBAC Configuration

The figure below shows a network in which TBAC is configured.

Figure 2 Sample TBAC Network


The following example verifies that RSVP and MPLS TE are enabled and coexist on the headend router (10.0.0.2 in the figure above): 

Router# show ip rsvp
RSVP: enabled (on 3 interface(s))
  RSVP QoS enabled <-------
  MPLS/TE signalling enabled <------
Signalling:
   Refresh interval (msec): 30000
   Refresh misses: 4
...

The following example verifies that RSVP and MPLS TE are enabled and coexist on the tailend router (10.0.0.3 in the figure above): 

Router# show ip rsvp
RSVP: enabled (on 3 interface(s))
  RSVP QoS enabled <-------
  MPLS/TE signalling enabled <------
Signalling:
   Refresh interval (msec): 30000
   Refresh misses: 4
...

The following examples verify that an IPv4 flow is traveling through a TE tunnel (a label-switched path [LSP]) on the headend router (10.0.0.2 in the figure above): 

Router# show ip rsvp sender
To              From          Pro DPort Sport Prev Hop       I/F      BPS
10.0.0.3        10.0.0.1      UDP 2     2     10.0.0.1       Et0/0    10K <-- IPv4 flow
10.0.0.3        10.0.0.2      0   1     11    none           none     100K <-- TE tunnel


Router# show ip rsvp reservation
To            From        Pro DPort Sport Next Hop     I/F    Fi Serv BPS
10.0.0.3      10.0.0.1    UDP 2     2     10.0.0.3     Tu1    SE RATE 10K <-- IPv4 flow
10.0.0.3      10.0.0.2    0   1     11    10.1.0.2     Et1/0  SE LOAD 100K <-- TE tunnel

The following examples verify that an IPv4 flow is traveling through a TE tunnel (LSP) on the tailend router (10.0.0.3 in the figure above): 

Router# show ip rsvp sender
To              From          Pro DPort Sport Prev Hop       I/F      BPS
10.0.0.3        10.0.0.1      UDP 2     2     10.0.0.2       Et1/0    10K <-- IPv4 flow
10.0.0.3        10.0.0.2      0   1     11    10.1.0.1       Et1/0    100K <-- TE tunnel


Router# show ip rsvp reservation
To            From          Pro DPort Sport Next Hop   I/F    Fi Serv BPS
10.0.0.3      10.0.0.1      UDP 2     2     none       none   SE RATE 10K <-- IPv4 flow
10.0.0.3      10.0.0.2      0   1     11    none       none   SE LOAD 100K <-- TE tunnel

The following examples display detailed information about the IPv4 flow and the TE tunnel (LSP) on the headend router (10.0.0.2 in the figure above): 

Router# show ip rsvp sender detail 
PATH: <----------------------------------------------- IPv4 flow information begins here.
  Destination 10.0.0.3, Protocol_Id 17, Don't Police , DstPort 2
  Sender address: 10.0.0.1, port: 2
  Path refreshes:
    arriving: from PHOP 10.0.0.10 on Et0/0 every 30000 msecs. Timeout in 189 sec
  Traffic params - Rate: 10K bits/sec, Max. burst: 10K bytes
    Min Policed Unit: 0 bytes, Max Pkt Size 2147483647 bytes
  Path ID handle: 02000412.
  Incoming policy: Accepted. Policy source(s): Default
  Status:
  Output on Tunnel1, out of band. Policy status: Forwarding. Handle: 0800040E <--- TE tunnel verified
    Policy source(s): Default
  Path FLR: Never repaired
PATH: <------------------------------------------------ TE tunnel information begins here.
  Tun Dest:   10.0.0.3  Tun ID: 1  Ext Tun ID: 10.0.0.2
  Tun Sender: 10.0.0.2  LSP ID: 11
  Path refreshes:
    sent:     to   NHOP 10.1.0.2 on Ethernet1/0
  ...

Router# show ip rsvp reservation detail
RSVP Reservation. Destination is 10.0.0.3, Source is 10.0.0.1,<--- IPv4 flow information begins here.
  Protocol is UDP, Destination port is 2, Source port is 2
  Next Hop: 10.0.0.3 on Tunnel1, out of band <-------------------- TE tunnel verified
  Reservation Style is Shared-Explicit, QoS Service is Guaranteed-Rate
  ...
Reservation: <--------------------------------------- TE Tunnel information begins here.
  Tun Dest:   10.0.0.3  Tun ID: 1  Ext Tun ID: 10.0.0.2
  Tun Sender: 10.0.0.2  LSP ID: 11
  Next Hop: 10.1.0.2 on Ethernet1/0
  Label: 0 (outgoing)
  Reservation Style is Shared-Explicit, QoS Service is Controlled-Load
  ...

Router# show ip rsvp installed detail
 
RSVP: Ethernet0/0 has no installed reservations
 
RSVP: Ethernet1/0 has the following installed reservations
RSVP Reservation. Destination is 10.0.0.3. Source is 10.0.0.2, 
  Protocol is 0  , Destination port is 1, Source port is 11
  Traffic Control ID handle: 03000405
  Created: 04:46:55 EST Fri Oct 26 2007 <------
 IPv4 flow information
  Admitted flowspec:
    Reserved bandwidth: 100K bits/sec, Maximum burst: 1K bytes, Peak rate: 100K bits/sec
    Min Policed Unit: 0 bytes, Max Pkt Size: 1500 bytes
  Resource provider for this flow: None
  ...
RSVP: Tunnel1 has the following installed reservations <------ TE tunnel verified
RSVP Reservation. Destination is 10.0.0.3. Source is 10.0.0.1, 
  Protocol is UDP, Destination port is 2, Source port is 2
  Traffic Control ID handle: 01000415
  Created: 04:57:07 EST Fri Oct 26 2007 <-----
 IPv4 flow information
  Admitted flowspec:
    Reserved bandwidth: 10K bits/sec, Maximum burst: 10K bytes, Peak rate: 10K bits/sec
    Min Policed Unit: 0 bytes, Max Pkt Size: 0 bytes
  Resource provider for this flow: None
  ...

Router# show ip rsvp interface detail
 
 
 Et0/0:
   RSVP: Enabled
   Interface State: Up
   Bandwidth:
     Curr allocated: 0 bits/sec
     Max. allowed (total): 3M bits/sec
     Max. allowed (per flow): 3M bits/sec
     ...
 Et1/0:
   RSVP: Enabled
   Interface State: Up
   Bandwidth:
     Curr allocated: 0 bits/sec
     Max. allowed (total): 3M bits/sec
     Max. allowed (per flow): 3M bits/sec
    ...
Tu1: <--------------------------------- TE tunnel information begins here.
   RSVP: Enabled
   RSVP aggregation over MPLS TE: Enabled
   Interface State: Up
   Bandwidth:
     Curr allocated: 20K bits/sec
     Max. allowed (total): 3M bits/sec
     Max. allowed (per flow): 3M bits/sec
     ...

The following examples display detailed information about the IPv4 flow and the TE tunnel (LSP) on the tailend router (10.0.0.3 in the figure above): 

Router# show ip rsvp sender detail
PATH: <----------------------------------------------- IPv4 flow information begins here.
  Destination 10.0.0.3, Protocol_Id 17, Don't Police , DstPort 2
  Sender address: 10.0.0.1, port: 2
  Path refreshes:
    arriving: from PHOP 10.0.0.2 on Et1/0 every 30000 msecs, out of band. Timeout in 188 sec
  Traffic params - Rate: 10K bits/sec, Max. burst: 10K bytes
    Min Policed Unit: 0 bytes, Max Pkt Size 2147483647 bytes
  ...
PATH: <------------------------------------------------ TE tunnel information begins here.
  Tun Dest:   10.0.0.3  Tun ID: 1  Ext Tun ID: 10.0.0.2
  Tun Sender: 10.0.0.2  LSP ID: 11
  Path refreshes:
    arriving: from PHOP 10.1.0.1 on Et1/0 every 30000 msecs. Timeout in 202 sec
  ...

Router# show ip rsvp reservation detail
 
RSVP Reservation. Destination is 10.0.0.3, Source is 10.0.0.1, <--- IPv4 flow information begins here.
  Protocol is UDP, Destination port is 2, Source port is 2
  Next Hop: none
  Reservation Style is Shared-Explicit, QoS Service is Guaranteed-Rate
  ...
 
Reservation: <--------------------------------------- TE tunnel information begins here.
  Tun Dest:   10.0.0.3  Tun ID: 1  Ext Tun ID: 10.0.0.2
  Tun Sender: 10.0.0.2  LSP ID: 11
  Next Hop: none
  Label: 1 (outgoing)
  Reservation Style is Shared-Explicit, QoS Service is Controlled-Load
  ...

Router# show ip rsvp request detail
 
RSVP Reservation. Destination is 10.0.0.3, Source is 10.0.0.1, 
  Protocol is UDP, Destination port is 2, Source port is 2
  Prev Hop: 10.0.0.2 on Ethernet1/0, out of band <-------------- TE tunnel verified
  Reservation Style is Shared-Explicit, QoS Service is Guaranteed-Rate
  Average Bitrate is 10K bits/sec, Maximum Burst is 10K bytes
  ...
 
Request: <------------------------------------ TE tunnel information begins here.
  Tun Dest:   10.0.0.3  Tun ID: 1  Ext Tun ID: 10.0.0.2
  Tun Sender: 10.0.0.2  LSP ID: 11
  Prev Hop: 10.1.0.1 on Ethernet1/0
  Label: 0 (incoming)
  Reservation Style is Shared-Explicit, QoS Service is Controlled-Load
  ...

Example Verifying the RSVP Local Policy Configuration

The following example verifies that a default local policy has been configured on tunnel interface 1:

Router# show run interface tunnnel 1
Building configuration...
 
Current configuration : 419 bytes
!
interface Tunnel1
 bandwidth 3000
 ip unnumbered Loopback0
 tunnel destination 10.0.0.3
 tunnel mode mpls traffic-eng
 tunnel mpls traffic-eng autoroute announce
 tunnel mpls traffic-eng priority 1 1
 tunnel mpls traffic-eng bandwidth 100
 tunnel mpls traffic-eng path-option 1 dynamic
 tunnel mpls traffic-eng fast-reroute
 ip rsvp policy local default <---------------- Local policy information begins here.
  max bandwidth single 10
  forward all
 ip rsvp bandwidth 3000
end

The following example provides additional information about the default local policy configured on tunnel interface 1:
Router# show ip rsvp policy local detail
Tunnel1:
  Default policy:
 
    Preemption Scope: Unrestricted.
    Local Override:   Disabled.
    Fast ReRoute:     Accept.
    Handle:           BC000413.
 
                           Accept               Forward
    Path:                  Yes                  Yes
    Resv:                  Yes                  Yes
    PathError:             Yes                  Yes
    ResvError:             Yes                  Yes
 
                           Setup Priority       Hold Priority
    TE:                    N/A                  N/A  
    Non-TE:                N/A                  N/A  
 
                           Current              Limit
    Senders:               0                    N/A
    Receivers:             1                    N/A
    Conversations:         1                    N/A
    Group bandwidth (bps): 10K                  N/A                 
    Per-flow b/w (bps):    N/A                  10K                 
 
Generic policy settings:
    Default policy: Accept all
    Preemption:     Disabled

Additional References

The following sections provide references related to the MPLS TE Tunnel-Based Admission Control (TBAC) feature.

Related Documents

Related Topic

Document Title

RSVP commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples

Cisco IOS Quality of Service Solutions Command Reference

QoS features including signaling, classification, and congestion management

"Quality of Service Overview" module

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

Standards

Standard

Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

--

MIBs

MIB

MIBs Link

No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

RFCs

RFC

Title

RFC 2205

Resource ReSerVation Protocol (RSVP)--Version 1 Functional Specification

RFC 2209

Resource ReSerVation Protocol (RSVP)--Version 1 Message Processing Rules

RFC 3175

Aggregation of RSVP for IPv4 and IPv6 Reservations

RFC 3209

RSVP-TE: Extensions to RSVP for LSP Tunnels

RFC 4804

Aggregation of Resource ReSerVation Protocol (RSVP) Reservations over MPLS TE/DS-TE Tunnels

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 MPLS TE-Tunnel-Based Admission Control

The following table provides release information about the feature or features described in this module. This table 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.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Table 1 Feature Information for MPLS TE--Tunnel-Based Admission Control (TBAC)

Feature Name

Releases

Feature Information

MPLS TE Tunnel-Based Admission Control (TBAC)

12.2(33)SRC

The MPLS TE--Tunnel-Based Admission Control (TBAC) feature enables classic Resource Reservation Protocol (RSVP) unicast reservations that are traveling across a Multiprotocol Label Switching Traffic Engineering (MPLS TE) core to be aggregated over an MPLS TE tunnel.

Glossary

admission control --The process by which an RSVP reservation is accepted or rejected on the basis of end-to-end available network resources.

aggregate--An RSVP flow that represents multiple E2E flows; for example, an MPLS-TE tunnel may be an aggregate for many E2E flows.

aggregation region --A area where E2E flows are represented by aggregate flows, with aggregators and deaggregators at the edge; for example, an MPLS-TE core, where TE tunnels are aggregates for E2E flows. An aggregation region contains a connected set of nodes that are capable of performing RSVP aggregation.

aggregator --The router that processes the E2E PATH message as it enters the aggregation region. This router is also called the TE tunnel headend router; it forwards the message from an exterior interface to an interior interface.

bandwidth --The difference between the highest and lowest frequencies available for network signals. The term is also used to describe the rated throughput capacity of a given network medium or protocol.

deaggregator --The router that processes the E2E PATH message as it leaves the aggregation region. This router is also called the TE tunnel tailend router; it forwards the message from an interior interface to an exterior interface.

E2E --end-to-end. An RSVP flow that crosses an aggregation region and whose state is represented in aggregate within this region; for example, a classic RSVP unicast flow that crosses an MPLS-TE core.

LSP --label-switched path. A configured connection between two routers, in which label switching is used to carry the packets. The purpose of an LSP is to carry data packets.

MPLS --Multiprotocol Label Switching. Packet-forwarding technology, used in the network core, that applies data link layer labels to tell switching nodes how to forward data, resulting in faster and more scalable forwarding than network layer routing normally can do.

QoS --quality of service. A measure of performance for a transmission system that reflects its transmission quality and service availability.

RSVP --Resource Reservation Protocol. A protocol that supports the reservation of resources across an IP network. Applications that run on IP end systems can use RSVP to indicate to other nodes the nature (bandwidth, jitter, maximum burst, and so on) of the packet streams that they want to receive.

state --Information that a router must maintain about each LSP. The information is used for rerouting tunnels.

TE --traffic engineering. The techniques and processes that are used to cause routed traffic to travel through the network on a path other than the one that would have been chosen if standard routing methods had been used.

tunnel --Secure communications path between two peers, such as two routers.

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