Unicast and Multicast Transmissions over the Network
A Unicast transmission sends IP packets to a single recipient on a network. A Multicast
transmission sends IP packets to a group of hosts on a network. If the streaming video is to be
distributed to a single destination, then you would start a Unicast stream by setting the
destination IP address and port on the IPTV device equal to the destination’s values. If you want to view
the stream at multiple concurrent locations, then you would set the IPTV device’s destination IP address
to a valid Multicast IP address (126.96.36.199 – 188.8.131.52).
Note that while the Multicast IP address range is from 184.108.40.206 – 220.127.116.11, the first octet
(224.xxx.xxx.xxx) is generally reserved for administration. We recommend setting the first octet
to 225 and the remaining three octets to the IPTV device’s IP address. For example, if the IPTV device IP
address is 192.168.1.53, then set the destination IP address to 18.104.22.168 for Multicast
Since Multicasting is a relatively new technology, some legacy devices that are part of your
network might not support Multicasting.
Before using the IPTV device in Multicast streaming mode, check the functional specifications of your
network infrastructure to ensure that the Multicast stream will not create major traffic on your
network. Verify that your backbone switch supports Internet Group Messaging Protocol (IGMP)
snooping, which allows the core of your network to ignore the traffic streams that Multicasting
IGMP Querying and IGMP Snooping
IGMP is a session-layer (Layer 3) protocol used to establish membership in a Multicast group
and can register a router to receive specific Multicast traffic. (Refer to RFC 1112 and RFC 2236
for information on IGMP versions 1 and 2.)
Multicast aware switches are slowly making their way into the network cores for businesses and
universities that have heavy traffic to move through their networks. Multicast filtering is achieved
by dynamic group control management. By default, all Multicast traffic should be blocked until
requested by a Multicast group member. (Default behavior depends on switch manufacturer.)
The master of the IGMP filter lists is the router or switch that is configured to act as the IGMP
Querier. The responsibility of the Querier is to send out IGMP group membership queries on a
timed interval, to retrieve IGMP membership reports from active members, and to allow updating
of the group membership tables.
A Layer 2 switch supporting IGMP Snooping can passively snoop on IGMP Query, Report, and
Leave (IGMP version 2) packets transferred between IP Multicast routers/switches and IP
Multicast hosts to determine the IP Multicast group membership. IGMP snooping checks IGMP
packets passing through the network, picks out the group registration, and configures
Connecting to the Network
Without IGMP Querying/Snooping, Multicast traffic is treated in the same manner as a Broadcast
transmission, which forwards packets to all ports on the network. With IGMP Querying/Snooping,
Multicast traffic is only forwarded to ports that are members of that Multicast group. IGMP
Snooping generates no additional network traffic, which significantly reduces the Multicast traffic
passing through your switch.
If your network distribution core does not support IGMP Querying/Snooping, the IPTV streams
will still function as designed but your network may be subjected to high traffic loads and
condensed collision domain due to the broadcasting action used by the older switch or hub. If this
is the case, you may wish to isolate the streaming nodes within the network so that the streams
may be viewed without crossing the normal network traffic along its path.
Otherwise, for a general performance improvement, you may consider upgrading your network
core to a switch that is Multicast aware.
DHCP IP Configuration
The IPTV device has Dynamic Host Configuration Protocol (DHCP) enabled as the factory default. If
your network has a DHCP server on it, the IPTV device will automatically acquire an IP address. If
the IPTV device is not able to find a DHCP server, it will default to the IP Address, Subnet Mask and
Gateway that are configured into the unit. The factory default IP address is 192.168.1.253.
To disable or enable DHCP on the IPTV device, use either the Console Interface (refer to section 5.1
Establishing a Connection) or the Browser Interface (refer to section 6.5.3 Device Network).
To assign a static IP address for the IPTV device, refer to the following section.
Static IP Configuration (Recommended Configuration)
If the IPTV device is not able to find a DHCP server, it will default to the IP Address, Subnet Mask
and Gateway that are configured into the unit. The factory default is 192.168.1.253.
It is strongly recommended that the IPTV device be statically configured to a specific IP address.
This enables the IPTV device to be consistently found at the same address. Prior to statically
configuring the IPTV device, check with your IT department and/or make sure the IP address to be
assigned is not in use by any other device on the LAN.
To assign a static IP address to the IPTV device, follow these steps:
- Power on the IPTV device blade and connect the console (light blue) and the network cables.
- Run a terminal emulation program such as TeraTerm to communicate via console (refer to
section 5.1 Establishing a Connection). Use the following communication parameters: Bits
per second (38400), Data bits (8), Parity (None), Stop bits (1), Flow Control (None).
- Press Enter to get the login prompt.
- Log in to the unit with the valid username/password (by default admin/admin).
Chapter 3 Connecting to the Network IPTV device User’s Manual
- An unconfigured unit automatically starts the Network Configuration Wizard, and will prompt
the user to enter an IP Address, Netmask, Gateway, and DNS Server.
- Once the values have been entered, the IPTV device should reboot and be accessible at its
newly assigned address. Type the unit’s IP address into a browser (http://xxx.xxx.xxx.xxx) to
bring up the IPTV device’s Browser Interface (refer to Chapter 6 Using the Browser Interface).
- For previously configured units, press “n” and then Enter from the Console Interface to
unlock the display and start the Network Configuration Wizard (see step 5 above).
- Units can be reconfigured at any time using the Console Interface as described in the