McDewey

Quality of Service for Voice over IP Resource Reservation Protocol 24 QoSVoIP.mif Deploying CAC Based on RSVP As already mentioned, you should deploy RSVP to improve VoIP QoS only where it can have a positive impact on quality and functionality. The benefits of using RSVP outweigh the costs only where bandwidth is limited. We recommend using Cisco IOS Release 12.1(5)T or a later release if you want to implement CAC for VoIP using RSVP. You need to complete the following three basic steps to configure CAC for VoIP calls using RSVP: • Enable synchronization between RSVP and the call signaling. (This synchronization is enabled by default when Cisco IOS Release 12.1(5)T or a later release is running. • Configure the voice gateways on both sides of the VoIP dial peers to request a particular QoS via RSVP. • Enable RSVP and specify the maximum bandwidth on all links that are traversed by voice packets where congestion is likely to occur. The following configuration example shows how to configure CAC for VoIP calls using RSVP: Configuration Example 10: Deploying CAC Using RSVP hostname LongBay ! isdn switch-type primary-ni call rsvp-sync ! controller T1 1/0 framing esf linecode b8zs pri-group timeslots 1-24 ! interface Ethernet0/0 ip address 10.0.152.254 255.255.255.0 ! interface Serial0/0 bandwidth 1536 ip address 10.10.1.1 255.255.255.0 encapsulation ppp ip tcp header-compression iphc-format ip rtp header-compression iphc-format ip rsvp bandwidth 1152 24 ! interface Serial1/0:23 no ip address no logging event link-status isdn switch-type primary-ni isdn incoming-voice voice no cdp enable !