ctly to the network. If users can get enough bandwidth, they are ways to transmit high- quality video, and moreover, there is no compression delay. SIP can fill the gap to build a high-quality videoconferencing system (end-to-end). DVTS is software that allows encapsulating DV format from a Firewire interface for transmission over IP networks, resulting in a high-quality DV stream that consumes roughly 30 Mbps of bandwidth. UltraGrid is a high definition (HD) video conferencing and distribution system. It is also considered one of the first systems capable of supporting © 2009 by Taylor & Francis Group, LLC SIP Handbook: Services, Technologies, and Security Cubicle 1 Cubicle 2 SIP call control submodule IP network (IPv6 & QoS) CS: Capture subsystem VAC: Video and audio coding subsystem SIP_UA GRS: Graphical rendering subsystem VS: Visualization subsystem LDAP client USS: User system interface subsystem signaling TRS: Transmission and reception subsystem SCS: System control subsystem FIGURE 2.17 TRS subsystem and SIP-CMI subsystem in Tifanis project. 1: Register 1: Register 2: 200 OK 2: 200 OK 3: Invite 4: Invite SIP server (SER) SIP client SIP client Signalling plane Media plane Ultragrid Videoconference HD Ultragrid Videoconference DV xdvshow xdvshow Videoconference DV FIGURE 2.18 HD video conferencing with SIP messages. uncompressed gigabit rate high definition video over IP. In fact, an Ultragrid node converts SMPTE 292M high definition video signals into RTP/UDP/IP packets, which can then be distributed across an IP network reaching trans- mission rates to 1.2 Gbps. There are few systems with these characteristics, such as iHDTV, i-Visto gateway [36]. The i2CAT Foundation research project called MACHINE has develo- ped an open-source graphical SIP UA to establish and control high-quality © 2009 by Taylor & Francis Group, LLC Analog audio Digital audio Alternative Analog video Possibility 1 Digital video audio Conversion DB 15 to DSUB 25 Analog audio Analog audio canon (XLR) Conversion (DSUB 25) until B channe