vii Index Vindigo, 713 Voice-grade lines, 18, 22 Virtual channels, ATM, 235-236 Voice over Frame Relay. See VoFR (Voice over Virtual circuits Frame Relay) defined, 216 Voice over IP. See VoIP (Voice over IP) MPLS with, 449 Voice over Wireless Local Area Network (VoWLAN), overview of, 9-10 648-651 packet-switched networks with, 217 VoIP (Voice over IP) PVCs, 10 call-signaling protocols, 330-339 SVCs, 10 delay, 325-326 Virtual containers, 127-128 digital voice technologies, 324-325 Virtual fiber (VF), 55, 529, 636-638 error concealment, 327 Virtual forwarding instances (VFI), 363-364 VS. IPT and Internet telephony, 314 Virtual mirrors, 1 IPTV supporting, 342 Virtual paths, ATM, 235-236 jitter buffers, 326 Virtual private dial networks (VPDNs), 359 limitation of IP networks, 240 Virtual Private LAN Service (VPLS) VPNs, lower costs of, 313 371-373 PacketCable 1.0 for, 518-519 Virtual private networks. See VPNs (virtual private QoS, 328-330 networks) service provider solutions for, 324 Virtual Private WAN Service (VPWS) VPNs, 371 UDP for, 170, 257 Virtual reality, xlix-1 VoWLAN (Voice over Wireless Local Area Net- Virtual router VPNs, 365, 367-369 work), 648-651 Virtual routing forwarding (VRF), 365-366 capacity and QoS, 649-650 Virtual tributaries, 127-128 cellular carrier cooperation with, 653-654 Viruses, 374 EDCA, 650 VLANs, 191-192 handoffs, 649 VLR (visitor location register), 586-587 Polled Access, 650 Vocoders, 324-325, 576-577 security, 648 VOD (video-on-demand) support solutions, 650-651 ADSL originally for, 503 VPDNs (virtual private dial networks), 359 for future cable TV, 521-522 VPLS (Virtual Private LAN Service) VPNs, IPTV supporting, 342-343 371-373 Metadata, 520-521 VPNs (virtual private networks), 345-381. See also Vodaphone, xxxvii IP VPNs VoDSL (Multiline Voice over DSL), 502 applications of, 354 VoFR (Voice over Frame Relay) ATM networks, 231 compression standards for, 228 benefits and evolution of, 357-358 features of, 228 BGP updated for, 264 overview of, 227-228 concepts, 347 voice activity det