NAT/Firewall穿越技术
常见的NAT种类
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Full Cone
Restricted Cone
Port Restricted Cone
Symmetric NAT
Full Cone
Restricted Cone(1/2)
Restricted Cone(2/2)
Port Restricted Cone
Symmetric NAT
NAT Detection Flow
防火牆造成的問題
NAT 造出的问题
NAT/Firewall穿越技术
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IPV6(Internet Protocol Version 6)
UPnP(Universal Plug and Play)
TRUN(Traversal Using Relay NAT)
ALG(Application Layer Gatewqy)
ICE(Interactive Connectivity Establish)
STUN(Simple Traversal of UDP
Through Netwoek Address Translators)
UPnP
Universal Plug and Play
It's being pushed by Microsoft
A UPnP-aware client can ask the UPnPenabled NAT how it would map a
particular IP:port through UPnP
UPnP Operation
STUN(1/2)
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Simple Traversal of UDP Through
Network Address Translators
需要在NAT外部架设 STUN Server
Client 端需有特殊的 STUN Client 功能
无法穿透 symmetric NAT
未来将被ICE整合
STUN(2/2)
TURN(1/2)
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Traversal Using Relay NAT
主要是为了解決 symmetric NATs
必须要架設 TURN Server
未来也将被包含进 ICE
TURN(2/2)
SIP using STUN
User Agent 1
NAT
10.2.1.1
192.0.2.101
STUN Server
User Agent 2
Registrar/Proxy
1 STUN SharedSecretRequest/TLS
2 STUN SharedSecretResponse/TLS
3 STUN BindingtRequest/UDP
4 STUN BindingResponse/UDP
5 REGISTER Contact:[email protected]
6 200 OK
7 INVITE Contact:[email protected]
9 100 Trying
8 INVITE Contact:[email protected]
10 200 OK
11 200 OK
12 ACK
13 ACK
RTP Media Session
SIP using TURN
User Agent 1
NAT 1
STUN/TURN Svr 1 Proxy STUN/TURN Svr 2
NAT 2
10.2.1.1
User Agent 2
192.168.1.1
1 STUN Requests
3 STUN Requests
2 STUN Responses
4 STUN Responses
5 INVITE
6 INVITE
7 180 Ringing
8 200 OK
9 ACK
10 ACK
11 Peer-to-Peer STUN Requests
12 Peer-to-Peer STUN Responses
13 Peer-to-Peer STUN Requests
14 Peer-to-Peer STUN Responses
RTP Media Session
Established using Derived Transport Addresses
ALG(1/2)
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Application Layer gateway
It Understands the signalling messages
and their relationship with the resulting
media flows.
It can modify the signalling to reflect the
public IP address and ports being used
by singalling and media traffic.
ALG(2/2)
ICE
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Interactive Connectivity Establishment
非 protocol 而是 framework
主要技术包括：STUN, TRUN, SIP
目前仍在RFC草案讨论阶段

HEIDENHAIN

ROD 600 Series

2014 - 2015 Short Course Meet Schedule