Cisco Systems CISCO1751 quick start Rsvp, Multilink PPP Interleaving, Configuring RSVP

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RSVP

Configuring Voice-over-IP

RSVP

Resource Reservation Protocol (RSVP) enables routers to reserve enough bandwidth on an interface for reliable and quality performance. RSVP works well on PPP, HDLC, and similar serial line interfaces. It does not work well on multi-access LANs.

You should configure RSVP if you have a serial interface and any of the following:

•Links slower than 2 Mbps

•Links with high utilization

•Need for the best possible voice quality

Note If you configure multilink PPP interleaving, you can use the ip rtp reserve command instead of configuring RSVP. Refer to the next section on “Multilink PPP Interleaving.”

Configuring RSVP

By default, RSVP is disabled so that it is backwards compatible with routers that do not implement it. To enable RSVP on an IP network, enter the ip rsvp bandwidth command from interface configuration mode. The following example enables RSVP on serial interface 0/0 and sets the maximum bandwidth to

96 kbps and the maximum bandwidth per single request to 24 kbps:

Router(config)# interface serial 0/0

Router(config-if)#ip rsvp bandwidth 96 24

The default maximum bandwidth is 75 percent of the bandwidth available on each interface.

RSVP must be enabled at each LAN or WAN interface that voice packets will travel across. After enabling RSVP you must also use the req-qosdial-peer configuration command to request an RSVP session on each VoIP dial peer. Otherwise, no bandwidth is reserved for voice traffic.

Router(config-dial-peer)# req-qoscontrolled-load

For further information about this command, refer to the Cisco 1751 Router Software Configuration Guide.

Multilink PPP Interleaving

Multilink PPP interleaving allows large packets to be multilink-encapsulated and fragmented into smaller packets to make sure that voice packets are transmitted without delay; small real-time packets, which are not multilink-encapsulated, are transmitted between fragments of the large packets. The interleaving feature also provides a special transmit queue for the smaller, delay-sensitive packets, enabling them to be transmitted earlier than other flows.

You should configure multilink PPP interleaving if you have a dialer, ISDN PRI or BRI interface, or a virtual template, and either of the following:

•Point-to-point connections using PPP encapsulation

•Links slower than 2 Mbps

Note Do not use multilink PPP on links faster than 2 Mbps.

Cisco 1751 Voice-over-IP Quick Start Guide

 

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Contents Audience, page Conventions, page Installing WAN and Voice Interface Cards, pageConfiguring Voice-over-IP, page List of Terms, page AudienceInstalling WAN and Voice Interface Cards If You Are Installing Voice Interface CardsConventions WIC and VIC Installation Procedure Figure 2 Inserting a WIC or VIC in the Router Connecting the FXS, FXO, and E&M VICs to the NetworkSignal Connector Pinouts for FXS, FXO, and E&M VICsRJ-48S Wiring for E&M Connectors Checking FXS VIC Installation2-Port ISDN BRI Card DescriptionConnecting the 2-Port ISDN BRI Card TE Interface use Determining Voice Port NumberingISDN BRI Card LEDs NT Interface useExample Cisco Router and Security Device ManagerConfiguring Voice-over-IP Configuration ToolsCisco ConfigMaker Application Cisco IOS Command-Line Interface Major Voice over IP Configuration TasksInformation for International Users Entering Configuration ModeRouter# show startup-config Saving the ConfigurationDial Plan Wildcards and Number ExpansionWestconfig-dial-peer# port 0/0 Extension Configuring FXS InterfacesNum-Exp Command Entry DestinationDial-Peer Tag Local Dial PeersTelephone Number Voice PortThese commands are summarized in Figure 919 FXS VIC 1/0 Destination PatternFigure 14 East Router Configured for Local Dial Peers Figure 13 Basic Voice Network East RouterDestination Pattern Checking Dial Peer ConfigurationCalling Between Routers Remote Location1919555 Remote Location Configuring FXO InterfacesChecking FXS Configuration Other Routers on the NetworkWest Figure 18 FXO Gateway to PSTNsignal wink-start immediate delay-dial Configuring E&M InterfacesChecking FXO Configuration CommandFigure 20 Linking PBXs over the IP Network Remote Dial Peers Checking E&M Interface Configuration Tuning Parameters for Real-Time Voice TrafficIP Precedence Need for Quality of ServiceConfiguring RSVP RSVPMultilink PPP Interleaving RTP Header Compression Configuring Multilink PPP InterleavingConfiguring RTP Header Compression Routerconfig-if# ip rtp reserve lowest-UDP-port range-of-portsConfiguring Frame Relay for VoIP List of Terms Obtaining Documentation Cisco.comOrdering Documentation Cisco Technical Support Website Submitting a Service RequestDocumentation Feedback Obtaining Technical AssistanceObtaining Additional Publications and Information Definitions of Service Request SeverityiQ Magazine is the quarterly publication from Cisco Systems designed to help growing companies learn how they can use technology to increase revenue, streamline their business, and expand services. The publication identifies the challenges facing these companies and the technologies to help solve them, using real-world case studies and business strategies to help readers make sound technology investment decisions. You can access iQ Magazine at this URL
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