![background image](http://html1.mh-extra.com/html/3com/vcx-v7122/vcx-v7122_user-manual_440856278.webp)
278
V7122 GatewayUser Guide
the gateway that if the PPPoE is disabled and no BootP server is activated, as required in
the gateway to use a PPPoE environment, then the gateway should use these defaults for its
IP configuration.
When
working with a PPPoE server (Access Concentrator) that does not reply to
LCP Echo messages (which by default, the gateway periodically sends) you may
want to disable the LCP Echo messages by using the ini file parameter
PPPoELCPEchoEnable. (For a description of this parameter, see
Networking
Parameters
.)
IP Multicasting
The gateway supports IP Multicasting level 1 according to RFC 2236 (that is IGMP version 2)
for RTP channels. The gateway is capable of transmitting and receiving Multicast packets.
Robust Reception of RTP Streams
This mechanism filters out unwanted RTP streams that are sent to the same port number on
the gateway. These multiple RTP streams can result from traces of previous calls, call
control errors and deliberate attacks.
When more than one RTP stream reaches the gateway on the same port number, the
gateway accepts only one of the RTP streams and rejects the rest of the streams. The RTP
stream is selected according to the following procedure:
The first packet arriving on a newly opened channel sets the source IP address and UDP
port from which further packets are received. Thus, the source IP address and UDP port
identify the currently accepted stream. If a new packet arrives whose source IP address or
UDP port are different to the currently accepted RTP stream, there are two options:
The new packet has a source IP address and UDP port which are the same as the
remote IP address and UDP port that were stated during the opening of the channel. In
this case, the gateway reverts to this new RTP stream.
The new packet has any other source IP address and UDP port, in which case the
packet is dropped.
Multiple Routers Support
Multiple routers support is designed to assist the media gateway when it operates in a
multiple routers network. The gateway learns the network topology by responding to ICMP
redirections and caches them as routing rules (with expiration time).
When a set of routers operating within the same subnet serve as gateways to that network
and intercommunicate using a dynamic routing protocol, the routers can determine the
shortest path to a certain destination and signal the remote host the existence of the better
route. Using multiple router support the media gateway can utilize these router messages to
change its next hop and establish the best path.
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 ...