McDewey

Quality of Service for Voice over IP VoIP QoS over ATM 40 QoSVoIP.mif Figure 11 VoIP QoS over ATM Links Two solutions are available for providing QoS to VoIP over an ATM network: one using separate data and voice VCs and one using shared data and voice VCs. VoIP QoS over ATM Solution Using Separate Data and Voice ATM PVCs For data and voice traffic sharing the same destination but requiring different QoS, you need to define groups of ATM VCs to form PVC bundles. In a PVC bundle, all the PVCs share the same source and destination, and each bundle is assigned to carry IP traffic with a specific IP Precedence level or range of levels. After you configure PVC bundles, you then configure each PVC with its specific ATM QoS parameters. As voice and data traffic with different IP Precedence levels arrives at the ATM interface of the router, Cisco IOS software dynamically sends it out on the appropriate PVC, effectively mapping IP QoS classes to ATM CoSs. The key benefits of implementing VoIP QoS using this method are as follows: • Automatic separation of voice and data traffic onto different PVCs. • Preservation of the differentiated services of the IP network through the ATM network. Cisco 7206 Cisco 7206 ATM switch ATM switch Ethernet switch Ethernet switch Ethernet switch Ethernet switch Ethernet switch Cisco 3640 VoIP gatekeeper Ethernet switch Cisco 3500 VoIP gateway AS5300 (8) PRI PRI Cisco 7505 Cisco 3640 VoIP gatekeeper Ethernet switch Cisco 3500 VoIP gateway AS5300 (8) PRI PRI 54743