![background image](http://html1.mh-extra.com/html/3com/vcx-v7122/vcx-v7122_user-manual_440856274.webp)
274
V7122 GatewayUser Guide
On startup the gateway sends a STUN Binding Request. The information received in the
STUN Binding Response (IP address:port) is used for SIP signaling. This information is
updated every NATBindingDefaultTimeout.
At the beginning of each call, if STUN is needed (that is, not an internal NAT call), the media
ports of the call are mapped. The call is delayed until the STUN Binding Response (that
includes a global IP:port) for each media (RTP, RTCP and T.38) is received.
To enable STUN:
Set the parameter EnableSTUN to 1
Define the STUN server address using one of the following methods:
Define the IP address of the primary and (optionally) the secondary, STUN servers
using the parameters STUNServerPrimaryIP and STUNServerSecondaryIP. If the
primary STUN server isn’t available, the gateway tries to communicate with the
secondary server.
Define the domain name of the STUN server using the StunServerDomainName
parameter. The STUN client retrieves all STUN servers with an SRV query to resolve
this domain name to an IP address and port, sort the server list, and use the servers
according to the sorted list.
Use the parameter NATBindingDefaultTimeout to determine the default NAT binding
lifetime in seconds. STUN is used to refresh the binding information after this time
expires.
•
STUN only applies to UDP (doesn’t support TCP and TLS).
•
STUN can’t be used when the gateway is located behind a symmetric NAT.
•
For defining the STUN server, use either the STUNServerPrimaryIP or
STUNServerDomainName parameter, with priority to the first one.
First Incoming Packet Mechanism
If the remote gateway resides behind a NAT device, it’s possible that the gateway can
activate the RTP/RTCP/T.38 streams to an invalid IP address / UDP port. To avoid such
cases, the gateway automatically compares the source address of the incoming
RTP/RTCP/T.38 stream with the IP address and UDP port of the remote gateway. If the two
are not identical, the transmitter modifies the sending address to correspond with the
address of the incoming stream. The RTP, RTCP and T.38 can thus have independent
destination IP addresses and UDP ports.
Users can choose to disable the NAT mechanism by setting the
ini
file parameter
‘DisableNAT’ to 1. The two parameters ‘EnableIpAddrTranslation’ and
‘EnableUdpPortTranslation’ enable users to specify the type of compare operation that takes
place on the first incoming packet. To compare only the IP address, set
‘EnableIpAddrTranslation = 1’ and ‘EnableUdpPortTranslation = 0’. In this case, if the first
incoming packet arrives with only a difference in the UDP port, the sending addresses won’t
change. If both the IP address and UDP port need to be compared, then both parameters
need to be set to 1.
Summary of Contents for VCX V7122
Page 28: ...28 V7122 GatewayUser Guide ...
Page 39: ...V7122 Gateway User Guide 39 Reader s Notes ...
Page 40: ...40 V7122 GatewayUser Guide ...
Page 58: ...58 V7122 GatewayUser Guide Reader s Notes ...
Page 66: ...66 V7122 GatewayUser Guide Reader s Notes ...
Page 144: ...144 V7122 GatewayUser Guide Reader s Notes ...
Page 239: ...V7122 Gateway User Guide 239 Reader s Notes ...
Page 240: ...240 V7122 GatewayUser Guide ...
Page 246: ...246 V7122 GatewayUser Guide Reader s Notes ...
Page 270: ...270 V7122 GatewayUser Guide Reader s Notes ...
Page 287: ...V7122 Gateway User Guide 287 Reader s Notes ...
Page 288: ...288 V7122 GatewayUser Guide ...
Page 294: ...294 V7122 GatewayUser Guide Reader s Notes ...
Page 300: ...300 V7122 GatewayUser Guide Figure 88 Gateway s Startup Process ...
Page 315: ...V7122 Gateway User Guide 315 Reader s Notes ...
Page 316: ...316 V7122 GatewayUser Guide ...
Page 332: ...332 V7122 GatewayUser Guide Reader s Notes ...
Page 358: ...358 V7122 GatewayUser Guide Reader s Notes ...
Page 362: ...362 V7122 GatewayUser Guide Reader s Notes ...
Page 389: ...V7122 Gateway User Guide 389 Reader s Notes ...
Page 390: ...390 V7122 GatewayUser Guide ...
Page 398: ...398 V7122 GatewayUser Guide Reader s Notes ...
Page 406: ...406 V7122 GatewayUser Guide Reader s Notes ...
Page 408: ...408 V7122 GatewayUser Guide Reader s Notes ...
Page 409: ...V7122 Gateway User Guide 409 ...
Page 419: ...V7122 Gateway User Guide 419 Reader s Notes ...
Page 437: ...V7122 Gateway User Guide 437 Reader s Notes ...
Page 452: ...452 V7122 GatewayUser Guide Figure 137 UDP2File Utility ...
Page 453: ...V7122 Gateway User Guide 453 Reader s Notes ...
Page 459: ...V7122 Gateway User Guide 459 Reader s Notes ...
Page 475: ...V7122 Gateway User Guide 475 ...