Symmetric NAT Traversal

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Tmedia supports passive NAT Traversal that addresses the need of peer VoIP endpoint having a private network address. This endpoint device is situated behind a NAT (Network Address Translation) device, e.g. Firewall, while the Tmedia VoIP port has a public IP address. For the passive mode, TMG detects the received RTP packet's source IP address and port. In response, Tmedia uses this source IP address and port as the packet destination for RTP.  
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Tmedia supports NAT (Network Address Translation) Traversal.
 
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== TelcoBridges and Passive NAT Traversal ==
 
== TelcoBridges and Passive NAT Traversal ==
Tmedia supports passive NAT Traversal starting from Tmedia release 2.6.31.
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Tmedia supports passive NAT Traversal that addresses the need of peer VoIP endpoint having a private network address. This endpoint device is situated behind a NAT device, e.g. Firewall, while the Tmedia VoIP port has a public IP address. For the passive mode, TMG detects the received RTP packet's source IP address and port. In response, Tmedia uses this source IP address and port as the packet destination for RTP.  
 
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Passive NAT traversal means the remote endpoint is behind a NAT.
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This is also called Remote NAT traversal or far-end NAT traversal.
 
This is also called Remote NAT traversal or far-end NAT traversal.
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== TelcoBridges and Active NAT Traversal ==
 
== TelcoBridges and Active NAT Traversal ==
Tmedia supports active NAT Traversal starting from Tmedia release 2.7.
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Active NAT traversal means the TMG endpoint is behind a NAT.  The Tmedia unit can advertise a public IP so that the remote device will know where to send the RTP traffic. It can also send the 'a=direction:active' in SIP SDP attribute so that the remote device puts itself in passive mode.
 
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Active NAT traversal means the TMG endpoint is behind a NAT.
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This is also called Local NAT traversal or near-end NAT traversal.  
 
This is also called Local NAT traversal or near-end NAT traversal.  

Revision as of 16:13, 11 August 2016

Tmedia supports NAT (Network Address Translation) Traversal.

Contents

TelcoBridges and Passive NAT Traversal

Tmedia supports passive NAT Traversal that addresses the need of peer VoIP endpoint having a private network address. This endpoint device is situated behind a NAT device, e.g. Firewall, while the Tmedia VoIP port has a public IP address. For the passive mode, TMG detects the received RTP packet's source IP address and port. In response, Tmedia uses this source IP address and port as the packet destination for RTP.

This is also called Remote NAT traversal or far-end NAT traversal.

TelcoBridges and Active NAT Traversal

Active NAT traversal means the TMG endpoint is behind a NAT. The Tmedia unit can advertise a public IP so that the remote device will know where to send the RTP traffic. It can also send the 'a=direction:active' in SIP SDP attribute so that the remote device puts itself in passive mode.

This is also called Local NAT traversal or near-end NAT traversal.

Typical Use Case

Passive nat traversal use case.jpg

Important Reminders

  • All devices in the path must support symmetric RTP/RTCP: RFC 4961


Configuration

External Sources

  • RFC 4961 Symmetric RTP / RTP Control Protocol (RTCP)


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