Chapter 1 Product Overview
What is Session Initiation Protocol?
Figure 1-1 SIP Architecture
SIP Proxy and
Redirect Servers
SIP
SIP | | SIP |
SIP User | | |
Agents (UA) | | SIP Gateway |
| |
| RTP | PSTN |
IP | |
| |
| | Legacy PBX |
SIP Clients
SIP clients include:
•Phones—Can act as either a UAS or UAC. Softphones (PCs that have phone capabilities installed) and Cisco SIP IP phones can initiate SIP requests and respond to requests.
•Gateways—Provide call control. Gateways provide many services, the most common being a translation function between SIP conferencing endpoints and other terminal types. This function includes translation between transmission formats and between communications procedures. In addition, the gateway also translates between audio and video codecs and performs call setup and clearing on both the LAN side and the switched-circuit network side.
| Cisco SIP IP Phone 7960 Administrator Guide |
1-4 | 78-10497-02 |
