文档介绍：SIP
会话发起协议
信息产业部电信传输研究所
互联网协议关系
OSPF
Ping
FTP
SIP
RTSP
RSVP
S/MGCP
/NCS
RTP/
RTCP
TCP
UDP
IP
IGMP
ICMP
ARP
RARP
Link Layer
1
2
信令标准
♦媒体网关控制信令
–
♦呼叫信令
– SIP和SIP T
–
SIP,
RTCP
RTP
IP
MGCP
Call Control and Signaling
Signaling and
Media
TCP
RAS
UDP
SIP
Gateway Control
Audio/
Video
RTSP
3
♦ 1995年开始研究
♦ 1996年作为ITU标准
♦被设计用在IP网上交换多媒体信息
♦主要部件
–终端
– GK
– GW
– MCU
• Multipoint Controller (MC)
• Multipoint Processor (MP)
♦必须支持
– call control signaling.
– control channel signaling.
– RTP/RTCP protocols for media packets.
– Audio codecs.
♦视频支持可选
4
♦地址翻译
–
–使用类系邮件地址
–使用电话号码
♦管理控制
–授权
–带宽限制
–控制局域网流量
♦管理网关
♦呼叫信令
♦呼叫管理
提供补充业务多点控制等
报告日志
♦提供全球连接
–
♦映射呼叫信令()
♦映射控制
to )
♦媒体映射
速率匹配
语音编码等
MCU
♦媒体分发
–单播
–组播
–混合
♦管理Ad Hoc多点呼叫
– Join, invite,控制会议模式
♦多协议
RTP
RTCP
Gate-
keeper
Reg,
Adm,
Status
(RAS)
Control
Data
Audio
Video
A/tl Control
TCP
UDP
IP
5
(7) ALERTING (8) CONNECT (User answers)
6
messages
over RAS channel
Gatekeeper
messages over
call signaling channel
messages over
call control channel
messages
over RAS channel
(optional)
messages (optional)
Terminal
(optional)
messages (optional)
PSTN
Gateway
♦ – A protocol for capabilities advertisement, media channel establishment and conference control.
♦ - Call Control.
♦- – A protocol for call control and call setup.
♦- RAS – Registration, admission and status protocol used municating between an endpoint and
a gatekeeper.
PictureTel
PictureTel
(1) ARQ
Can I call
“Bob”?
(3) ACF
Yes, use this
Bill
Bob
GK
IP Address (4) SETUP (Create)
(2a) GK resolves “Bob”
to IP address through H.