IP Setup 6-33
Multicast Forwarding
Multicast is a method for transmitting large amounts of information to many, but not all, hosts over an Internet.
One common use is to distribute real time audio and video to the set of hosts which have joined a distributed
conference.
Multicast is similar to radio or TV broadcasts in the sense that only those who have tuned in to a particular
frequency receive the information. You see and hear the channel you are interested in, but not the others.
Since a gateway should not be used as a passive forwarding device, Netopia gateways use a protocol for
forwarding multicasting. This protocol is Internet Group Management Protocol (IGMP). Two versions of IGMP are
available, V1 and V2. Netopia gateways can use either one, however, Multicast Forwarding will only work if your
service provider supports it. Check with your service provider.
You configure Multicast Forwarding in two Telnet menu screens:
• First, you enable Multicast Forwarding in the IP Setup screen in the System Configuration menu,
• Then you associate it with a Connection Profile in the IP Profile Parameters screen in the
Add/Display/Change Connection Profile menus.
Navigate to the IP Setup screen.
By default, Multicast Forwarding is tuned off (None). You enable the gateway to transmit multicast data by
selecting Tx. from the pull-down menu.
If you enable Multicast Forwarding, you will see a new option IGMP Version. This lets you choose V1 or V2. If
you know you will be communicating with other hosts that are limited to V1, select V1; otherwise, allow the
default V2.
Navigate to the IP Profile Parameters screen.
IP
System Configuration
Main
Menu Setup
IP Setup
Ethernet IP Address: 192.168.1.1
Ethernet Subnet Mask: 255.255.255.0
Define Additional Subnets...
Default IP Gateway: 0.0.0.0
Backup IP Gateway: 0.0.0.0
Primary Domain Name Server: 0.0.0.0
Secondary Domain Name Server: 0.0.0.0
Domain Name:
Receive RIP... Both
Transmit RIP... +----------------+
Multicast Forwarding... +----------------+
IGMP Version... | None |
| Tx. |
+----------------+
Static Routes... IP Address Serving...
