Network Considerations; Assigning Multicast Addresses; Vbrick Accessories; Serial Port Passthrough - VBrick 9000 Series Getting Started Manual

Network Considerations

Assigning Multicast Addresses

Many factors must be considered when designing a multicast address infrastructure since
Ethernet switch implementations can significantly vary between vendors. Furthermore,
multicast addressing techniques rely on an Ethernet to IP Address mapping rule, which does
not guarantee a unique physical address. In fact, it is possible to create multicast addresses
that differ from an IP perspective, but overlap when presented to the Ethernet network.
Addresses created in this situation can cause significant network and operational problems.
Specifically, multiple IP Addresses are mapped into the same physical layer address. For
example, all IP multicast addresses with the same or differing first octet, and the second octet
differing by exactly 128, map to the same physical address (226.5.5.4, 227.5.5.4, and
228.133.5.4 all map to the same physical address). Another factor to keep in mind when
assigning multicast addresses is that 224.x.x.x is a range containing reserved addresses,
particularly in the range 224.0.0.x. For example, 224.0.0.1 is the 'all hosts' multicast address
and 224.0.0.2 is the 'all routers' reserved address. Other 224.0.0.X numbers are reserved for
RIP, OSPF, DVMRP, etc. Here are some recommended rules for multicast IP Address
assignment:
1. Do not use 224 in the first octet since many of these are reserved.
2. Use a digit between (225–239) for the first octet and standardize on it for each network.
3. In the second octet, either use numbers from 1–127, or 129–255, do not mix ranges on a
given network.

VBrick Accessories

VBrick appliances have various optional hardware accessories. These work directly with
VBrick appliances or through the use of ActiveX control software, also available from
VBrick. For information about microphones, cameras and other VBrick hardware
accessories, please contact VBrick directly. ActiveX controls for cameras and other software
accessories are also available from VBrick.

Serial Port Passthrough

When configured properly, VBricks provide full duplex, end-to-end transparent passthrough
of user data from one VBrick to another, or to other IP devices. You can use COM1 or
COM2 for passthrough. When COM1 Passthrough is enabled, the management port and CLI
are not available. The serial ports operate at the configured baud rate (e.g. 110 to 115.2K
bps). See the H.264 Admin Guide for passthrough configuration details. Some common
applications include:
• Remote control of a camera, pan-tilt-zoom.
• Remote control of a security door lock.
• Low speed data transport.
• Data collaboration between PCs.
Note Passthrough mode is used to send control information from one VBrick to another
and may not support sustained data at higher data rates.
56 © 2012 VBrick Systems, Inc.