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RSVP Scalability Enhancements

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RSVP Scalability Enhancements

Finding Feature Information

Contents

Prerequisites for RSVP Scalability Enhancements

Restrictions for RSVP Scalability Enhancements

Information About RSVP Scalability Enhancements

Benefits of RSVP Scalability Enhancements

How to Configure RSVP Scalability Enhancements

Configuring the Resource Provider

Disabling Data Packet Classification

Configuring Class Maps and Policy Maps

Attaching a Policy Map to an Interface

Verifying RSVP Scalability Enhancements Configuration

Monitoring and Maintaining RSVP Scalability Enhancements

Configuration Examples for RSVP Scalability Enhancements

Examples: Configuring the Resource Provider as None with Data Classification Turned Off

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Feature Information for RSVP Scalability Enhancements

Glossary


RSVP Scalability Enhancements

First Published: August 1, 2001
Last Updated: February 26, 2010

This document describes the Cisco Resource Reservation Protocol (RSVP) scalability enhancements. It provides an overview of the feature, includes configuration tasks and examples, and lists related Cisco IOS command-line interface (CLI) commands.

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 RSVP Scalability Enhancements" section.

Use Cisco Feature Navigator to find information about platform support and Ciscosoftware 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 RSVP Scalability Enhancements

•Restrictions for RSVP Scalability Enhancements

•Information About RSVP Scalability Enhancements

•How to Configure RSVP Scalability Enhancements

•Configuration Examples for RSVP Scalability Enhancements

•Additional References

•Feature Information for RSVP Scalability Enhancements

•Glossary

Prerequisites for RSVP Scalability Enhancements

The network must support the following Cisco IOS XE features before the RSVP scalability enhancements are enabled:

•Resource Reservation Protocol (RSVP)

•Class-based weighted fair queueing (CBWFQ)

Restrictions for RSVP Scalability Enhancements

•Sources should not send marked packets without an installed reservation.

•Sources should not send marked packets that exceed the reserved bandwidth.

•Sources should not send marked packets to a destination other than the reserved path.

Information About RSVP Scalability Enhancements

RSVP typically performs admission control, classification, policing, and scheduling of data packets on a per-flow basis and keeps a database of information for each flow. RSVP scalability enhancements let you select a resource provider (formerly called a quality of service (QoS) provider) and disable data packet classification so that RSVP performs admission control only. This facilitates integration with service provider (differentiated services (DiffServ)) networks and enables scalability across enterprise networks.

CBWFQ provides the classification, policing, and scheduling functions. CBWFQ puts packets into classes based on the differentiated services code point (DSCP) value in the packet's Internet Protocol (IP) header, thereby eliminating the need for per-flow state and per-flow processing.

Figure 1 shows two enterprise networks interconnected through a service provider (SP) network. The SP network has an IP backbone configured as a DiffServ network. Each enterprise network has a voice gateway connected to an SP edge/aggregation router via a wide area network (WAN) link. The enterprise networks are connected to a private branch exchange (PBX).

Figure 1

RSVP/DiffServ Integration Topology

The voice gateways are running classic RSVP, which means RSVP is keeping a state per flow and also classifying, marking, and scheduling packets on a per flow basis. The edge/aggregation routers are running classic RSVP on the interfaces (labeled C and D) connected to the voice gateways and running RSVP for admission control only on the interfaces connected to core routers 1 and 3. The core routers in the DiffServ network are not running RSVP, but are forwarding the RSVP messages to the next hop. The core routers inside the DiffServ network implement a specific per hop behavior (PHB) for a collection of flows that have the same DSCP value.

The voice gateways identify voice data packets and set the appropriate DSCP in their IP headers such that the packets are classified into the priority class in the edge/aggregation routers and in core routers 1, 2, 3 or 1, 4, 3.

The interfaces or the edge/aggregation routers (labeled A and B) connected to core routers 1 and 3 are running RSVP, but are doing admission control only per flow against the RSVP bandwidth pool configured on the DiffServ interfaces of the edge/aggregation routers. CBWFQ is performing the classification, policing, and scheduling functions.

Benefits of RSVP Scalability Enhancements

Enhanced Scalability

RSVP scalability enhancements handle similar flows on a per-class basis instead of a per-flow basis. Since fewer resources are required to maintain per-class QoS guarantees, the RSVP scability enhancements provide faster processing results, thereby enhancing scalability.

Improved Router Performance

RSVP scalability enhancements improve router performance by reducing the cost for data-packet classification and scheduling, which decrease CPU resource consumption. The saved resources can then be used for other network management functions.

How to Configure RSVP Scalability Enhancements

This section contains the following tasks:

•Configuring the Resource Provider (required)

•Disabling Data Packet Classification (required)

•Configuring Class Maps and Policy Maps (required)

•Attaching a Policy Map to an Interface (required)

•Verifying RSVP Scalability Enhancements Configuration (optional)

Configuring the Resource Provider

Note The resource provider was formerly called the QoS provider.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type slot/subslot/port

4. ip rsvp bandwidth [interface-kbps [single-flow-kbps [bc1 kbps | sub-pool kbps]] | percent percent-bandwidth [single-flow-kbps]]

5. ip rsvp resource-provider none

6. end

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

•Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

interface type slot/subslot/port

Example:

Router(config)# interface gigabitEthernet 0/0/0

Configures the interface type and enters interface configuration mode.

Step 4 

ip rsvp bandwidth [interface-kbps [single-flow-kbps [bc1 kbps | sub-pool kbps]] | percent percent-bandwidth [single-flow-kbps]]









Example:

Router(config-if)# ip rsvp bandwidth 7500 7500

Enables RSVP 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. Range is from 1 to 10000000.

•The optional sub-pool and kbps keyword and argument specify subpool traffic and the amount of bandwidth that can be allocated by RSVP flows. Range is from 1 to 10000000.

Note Repeat this command for each interface on which you want to enable RSVP.

Note The bandwidth that you configure on the interface must match the bandwidth that you configure for the CBWFQ priority queue.

Step 5 

ip rsvp resource-provider none

Example:

Router(config-if)# ip rsvp resource-provider none

Sets the resource provider to none.

Note Setting the resource provider to none instructs RSVP to not associate any resources, such as WFQ queues or bandwidth, with a reservation.

Step 6 

end

Example:

Router(config-if)# end

(Optional) Returns to privileged EXEC mode.


Disabling Data Packet Classification

Perform the following task to disable data packet classification. Disabling data packet classification instructs RSVP not to process every packet, but to perform admission control only.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type slot/subslot/port

4. ip rsvp data-packet classification none

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 type slot/subslot/port

Example:

Router(config)# interface gigabitEthernet0/0/0

Configures the interface type and enters interface configuration mode.

Step 4 

ip rsvp data-packet classification none

Example:

Router(config-if)# ip rsvp data-packet classification none

Disables data packet classification.

Step 5 

end

Example:

Router(config-if)# end

(Optional) Returns to privileged EXEC mode.


Configuring Class Maps and Policy Maps

SUMMARY STEPS

1. enable

2. configure terminal

3. class-map class-map-name

4. exit

5. policy-map policy-map-name

6. end

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

•Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

class-map class-map-name

Example:

Router(config)# class-map class1

Specifies the name of the class for which you want to create or modify class-map match criteria and enters the class map configuration mode.

Step 4 

exit

Example:

Router(config-cmap)# exit

Returns to the global configuration mode.

Step 5 

policy-map policy-map-name

Example:

Router(config)# policy-map policy1

Specifies the name of the policy map to be created, added to, or modified before you can configure policies for classes whose match criteria are defined in a class map.

Step 6 

end

Example:

Router(config-control-policymap)# end

(Optional) Returns to privileged EXEC mode.


Attaching a Policy Map to an Interface

Perform the following task to attach a policy map to an interface. If at the time you configure the RSVP scalability enhancements, there are existing reservations that use classic RSVP, no additional marking, classification, or scheduling is provided for these flows. You can also delete these reservations after you configure the RSVP scalability enhancements.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type slot/subslot/port

4. service-policy {input | output} policy-map-name

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 type slot/subslot/port

Example:

Router(config)# interface gigabitEthernet 0/0/0

Configures the interface type and enters interface configuration mode.

Step 4 

service-policy {input | output} policy-map-name

Example:

Router(config-if)# service-policy input policy1

Attaches a single policy map to one or more interfaces to specify the service policy for those interfaces.

Step 5 

end

Example:

Router(config-if)# end

(Optional) Returns to privileged EXEC mode.


Verifying RSVP Scalability Enhancements Configuration

Step 1 Enter the show ip rsvp interface detail command to display information about interfaces, subinterfaces, resource providers, and data packet classification. The output in the following example shows that the ATM interface 6/0 has resource provider none configured and that data packet classification is turned off: 

Router# show ip rsvp interface detail


 AT6/0:

   Bandwidth:

     Curr allocated: 190K bits/sec

     Max. allowed (total): 112320K bits/sec

     Max. allowed (per flow): 112320K bits/sec

   Neighbors:

     Using IP encap: 1.  Using UDP encaps: 0

   DSCP value used in Path/Resv msgs: 0x30

   RSVP Data Packet Classification is OFF

   RSVP resource provider is: none

Note The last two lines in the preceding output verify that the RSVP scalability enhancements (disabled data packet classification and resource provider none) are present.

Step 2 Enter the show ip rsvp installed detail command to display information about interfaces, subinterfaces, their admitted reservations, bandwidth, resource providers, and data packet classification. 

Router# show ip rsvp installed detail


RSVP: GigabitEthernet0/0/0 has no installed reservations


RSVP: ATM6/0 has the following installed reservations

RSVP Reservation. Destination is 10.20.20.212, Source is 10.10.10.211, 

  Protocol is UDP, Destination port is 14, Source port is 14

  Reserved bandwidth: 50K bits/sec, Maximum burst: 1K bytes, Peak rate: 50K bits/sec

  Min Policed Unit: 0 bytes, Max Pkt Size: 1514 bytes

  Resource provider for this flow: None

  Conversation supports 1 reservations

  Data given reserved service: 0 packets (0 bytes)

  Data given best-effort service: 0 packets (0 bytes)

  Reserved traffic classified for 54 seconds

  Long-term average bitrate (bits/sec): 0M reserved, 0M best-effort

RSVP Reservation. Destination is 10.20.20.212, Source is 10.10.10.211, 

  Protocol is UDP, Destination port is 10, Source port is 10

  Reserved bandwidth: 20K bits/sec, Maximum burst: 1K bytes, Peak rate: 20K bits/sec

  Min Policed Unit: 0 bytes, Max Pkt Size: 1514 bytes

  Resource provider for this flow: None

  Conversation supports 1 reservations

  Data given reserved service: 0 packets (0 bytes)

  Data given best-effort service: 0 packets (0 bytes)

  Reserved traffic classified for 80 seconds

  Long-term average bitrate (bits/sec): 0M reserved, 0M best-effort

Step 3 Wait for a while, then enter the show ip rsvp installed detail command again. In the following output, notice there is no increment in the number of packets classified: 

Router# show ip rsvp installed detail


RSVP: Ethernet3/3 has no installed reservations


RSVP: ATM6/0 has the following installed reservations

RSVP Reservation. Destination is 10.20.20.212, Source is 10.10.10.211, 

  Protocol is UDP, Destination port is 14, Source port is 14

  Reserved bandwidth: 50K bits/sec, Maximum burst: 1K bytes, Peak rate: 50K bits/sec

  Min Policed Unit: 0 bytes, Max Pkt Size: 1514 bytes

  Resource provider for this flow: None

  Conversation supports 1 reservations

  Data given reserved service: 0 packets (0 bytes)

  Data given best-effort service: 0 packets (0 bytes)

  Reserved traffic classified for 60 seconds

  Long-term average bitrate (bits/sec): 0 reserved, OM best-effort

RSVP Reservation. Destination is 10.20.20.212, Source is 10.10.10.211, 

  Protocol is UDP, Destination port is 10, Source port is 10

  Reserved bandwidth: 20K bits/sec, Maximum burst: 1K bytes, Peak rate: 20K bits/sec

  Min Policed Unit: 0 bytes, Max Pkt Size: 1514 bytes

  Resource provider for this flow: None

  Conversation supports 1 reservations

  Data given reserved service: 0 packets (0 bytes)

  Data given best-effort service: 0 packets (0 bytes)

  Reserved traffic classified for 86 seconds

  Long-term average bitrate (bits/sec): OM reserved, 0M best-effort

Monitoring and Maintaining RSVP Scalability Enhancements

To monitor and maintain RSVP scalability enhancements, use the following commands in EXEC mode. The following commands can be entered in any order.

Command
Purpose

Router# show ip rsvp installed

Displays information about interfaces and their admitted reservations.

Router# show ip rsvp installed detail

Displays additional information about interfaces and their admitted reservations.

Router# show ip rsvp interface

Displays RSVP-related interface information.

Router# show ip rsvp interface detail

Displays additional RSVP-related interface information.

Router# show queueing [custom | fair | priority | random-detect [interface serial-number]]

Displays all or selected configured queueing strategies and available bandwidth for RSVP reservations.


Configuration Examples for RSVP Scalability Enhancements

•Examples: Configuring the Resource Provider as None with Data Classification Turned Off

Examples: Configuring the Resource Provider as None with Data Classification Turned Off

Following is output from the show ip rsvp interface detail command before a resource provider is configured as none and data-packet classification is turned off: 

Router# show ip rsvp interface detail


 AT6/0:

   Bandwidth:

     Curr allocated: 190K bits/sec

     Max. allowed (total): 112320K bits/sec

     Max. allowed (per flow): 112320K bits/sec

   Neighbors:

     Using IP encap: 1.  Using UDP encaps: 0

   DSCP value used in Path/Resv msgs: 0x30

Following is the output from the show queueing command before a resource provider is configured as none and data packet classification is turned off: 

Router# show queueing int atm6/0


  Interface ATM6/0 VC 200/100 

  Queueing strategy: weighted fair

  Output queue: 63/512/64/3950945 (size/max total/threshold/drops)

     Conversations  2/5/64 (active/max active/max total)

     Reserved Conversations 0/0 (allocated/max allocated)

     Available Bandwidth 450 kilobits/sec

Note New reservations do not reduce the available bandwidth (450 kilobits/sec shown above). Instead RSVP performs admission control only using the bandwidth limit configured in the ip rsvp bandwidth command. The bandwidth configured in this command should match the bandwidth configured in the CBWFQ class that you set up to handle the reserved traffic.

The following example shows how to configure resource provider as none: 

Router# configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)# interface atm6/0

Router(config-if)# ip rsvp resource-provider none 

Router(config-if)# end

Router#

The following example shows how to turn off the data packet classification: 

Router# configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)# interface atm6/0

Router(config-if)# ip rsvp data-packet classification none 

Router(config-if)# end

Following is the output from the show ip rsvp interface detail command after resource provider has been configured as none and data packet classification has been turned off: 

Router# show ip rsvp interface detail


 AT6/0:

   Bandwidth:

     Curr allocated: 190K bits/sec

     Max. allowed (total): 112320K bits/sec

     Max. allowed (per flow): 112320K bits/sec

   Neighbors:

     Using IP encap: 1.  Using UDP encaps: 0

   DSCP value used in Path/Resv msgs: 0x30

   RSVP Data Packet Classification is OFF

   RSVP resource provider is: none

The following output from the show ip rsvp installed detail command verifies that resource provider none is configured and data packet classification is turned off: 

Router# show ip rsvp installed detail


RSVP: ATM6/0 has the following installed reservations

RSVP Reservation. Destination is 10.20.20.212, Source is 10.10.10.211, 

  Protocol is UDP, Destination port is 14, Source port is 14

  Reserved bandwidth: 50K bits/sec, Maximum burst: 1K bytes, Peak rate: 50K bits/sec

  Min Policed Unit: 0 bytes, Max Pkt Size: 1514 bytes

  Resource provider for this flow: None

  Conversation supports 1 reservations

  Data given reserved service: 3192 packets (1557696 bytes)

  Data given best-effort service: 42 packets (20496 bytes)

  Reserved traffic classified for 271 seconds

  Long-term average bitrate (bits/sec): 45880 reserved, 603 best-effort

RSVP Reservation. Destination is 10.20.20.212, Source is 10.10.10.211, 

  Protocol is UDP, Destination port is 10, Source port is 10

  Reserved bandwidth: 20K bits/sec, Maximum burst: 1K bytes, Peak rate: 20K bits/sec

  Min Policed Unit: 0 bytes, Max Pkt Size: 1514 bytes

  Resource provider for this flow: None

  Conversation supports 1 reservations

  Data given reserved service: 1348 packets (657824 bytes)

  Data given best-effort service: 0 packets (0 bytes)

  Reserved traffic classified for 296 seconds

  Long-term average bitrate (bits/sec): 17755 reserved, 0M best-effort

The following output shows no increments in packet counts after the source sends data packets that match the reservation: 

Router# show ip rsvp installed detail


RSVP: GigabitEthernet3/3 has no installed reservations


RSVP: ATM6/0 has the following installed reservations

RSVP Reservation. Destination is 10.20.20.212, Source is 10.10.10.211,

  Protocol is UDP, Destination port is 14, Source port is 14

  Reserved bandwidth: 50K bits/sec, Maximum burst: 1K bytes, Peak rate: 50K bits/sec

  Min Policed Unit: 0 bytes, Max Pkt Size: 1514 bytes

  Resource provider for this flow: None

  Conversation supports 1 reservations

  Data given reserved service: 3192 packets (1557696 bytes)

  Data given best-effort service: 42 packets (20496 bytes)

  Reserved traffic classified for 282 seconds

  Long-term average bitrate (bits/sec): 44051 reserved, 579 best-effort

RSVP Reservation. Destination is 145.20.20.212, Source is 145.10.10.211, 

  Protocol is UDP, Destination port is 10, Source port is 10

  Reserved bandwidth: 20K bits/sec, Maximum burst: 1K bytes, Peak rate: 20K bits/sec

  Min Policed Unit: 0 bytes, Max Pkt Size: 1514 bytes

  Resource provider for this flow: None

  Conversation supports 1 reservations

  Data given reserved service: 1348 packets (657824 bytes)

  Data given best-effort service: 0 packets (0 bytes)

  Reserved traffic classified for 307 seconds

  Long-term average bitrate (bits/sec): 17121 reserved, 0M best-effort

The following output verifies that data packet classification is occurring: 

Router# show ip rsvp installed detail


Enter configuration commands, one per line.  End with CNTL/Z.

RSVP: ATM6/0 has the following installed reservations

RSVP Reservation. Destination is 10.20.20.212, Source is 10.10.10.211, 

  Protocol is UDP, Destination port is 14, Source port is 14

  Reserved bandwidth: 50K bits/sec, Maximum burst: 1K bytes, Peak rate: 50K bits/sec

  Min Policed Unit: 0 bytes, Max Pkt Size: 1514 bytes

  Resource provider for this flow: None

  Conversation supports 1 reservations

  Data given reserved service: 3683 packets (1797304 bytes)

  Data given best-effort service: 47 packets (22936 bytes)

  Reserved traffic classified for 340 seconds

  Long-term average bitrate (bits/sec): 42201 reserved, 538 best-effort

RSVP Reservation. Destination is 10.20.20.212, Source is 10.10.10.211, 

  Protocol is UDP, Destination port is 10, Source port is 10

  Reserved bandwidth: 20K bits/sec, Maximum burst: 1K bytes, Peak rate: 20K bits/sec

  Min Policed Unit: 0 bytes, Max Pkt Size: 1514 bytes

  Resource provider for this flow: None

  Conversation supports 1 reservations

  Data given reserved service: 1556 packets (759328 bytes)

  Data given best-effort service: 0 packets (0 bytes)

  Reserved traffic classified for 364 seconds

  Long-term average bitrate (bits/sec): 16643 reserved, 0M best-effort

Note You can use debug ip rsvp traffic-control and debug ip rsvp wfq simultaneously. Use the show debug command to see which debugging commands are enabled.

Additional References

The following sections provide references related to the RSVP Scalability Enhancements feature.

Related Documents

Related Topic
Document Title

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

QoS commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples

Cisco IOS Quality of Service Solutions Command Reference

QoS configuration tasks related to RSVP

"Configuring RSVP" module


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

None

To locate and download MIBs for selected platforms, software 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

RFC 2206

RSVP Management Information Base using SMIv2


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 RSVP Scalability Enhancements

Table 1 lists the release history for this feature.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Note Table 1 lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Table 1 Feature Information for RSVP Scalability Enhancements 

Feature Name
Releases
Feature Information

RSVP Scalability Enhancements

Cisco IOS XE Release 2.6

RSVP scalability enhancements let you select a resource provider (formerly called a QoS provider) and disable data packet classification so that RSVP performs admission control only. This facilitates integration with service provider (DiffServ) networks and enables scalability across enterprise networks.

The following commands were introduced or modified: debug ip rsvp traffic-control, debug ip rsvp wfq, ip rsvp data-packet classification none, ip rsvp resource-provider, show ip rsvp installed, show ip rsvp interface, show queueing.


Glossary

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

aggregate—A collection of packets with the same DSCP.

bandwidth—The difference between the highest and lowest frequencies available for network signals. This term also describes the rated throughput capacity of a given network medium or protocol.

CBWFQ—class-based weighted fair queueing. A queueing mechanism that extends the standard WFQ functionality to provide support for user-defined traffic classes.

DiffServ—differentiated services. An architecture based on a simple model where traffic entering a network is classified and possibly conditioned at the boundaries of the network. The class of traffic is then identified with a DS code point or bit marking in the IP header. Within the core of the network, packets are forwarded according to the per-hop behavior associated with the DS code point.

DSCP—differentiated services code point. The six most significant bits of the 1-byte IP type of service (ToS) field. The per-hop behavior represented by a particular DSCP value is configurable. DSCP values range between 0 and 63.

enterprise network—A large and diverse network connecting most major points in a company or other organization.

flow—A stream of data traveling between two endpoints across a network (for example, from one LAN station to another). Multiple flows can be transmitted on a single circuit.

packet—A logical grouping of information that includes a header containing control information and (usually) user data. Packets most often refer to network-layer units of data.

PBX—private branch exchange. A digital or analog telephone switchboard located on the subscriber premises and used to connect private and public telephone networks.

PHB—per-hop behavior. A DiffServ concept that specifies how specifically marked packets are to be treated by each DiffServ router.

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 for reserving network resources to provide quality of service guarantees to application flows.

Voice over IP—See VoIP.

VoIP—Voice over IP. The ability to carry normal telephony-style voice over an IP-based internet maintaining telephone-like functionality, reliability, and voice quality.

WFQ—weighted fair queueing. A queue management algorithm that provides a certain fraction of link bandwidth to each of several queues, based on the relative bandwidth applied to each of the queues.

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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

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