NETGEAR ProSafe GSM7224 User Manual page 220

User Manual for the NETGEAR 7200 Series Layer 2 Managed Switch Software
Multicast Backbone
The MBONE is a virtual network. It is layered on top of portions of the physical Internet to support routing
of IP multicast packets since that function has not yet been integrated into many production routers. The
network is composed of islands that can directly support IP multicast, such as multicast LANs like Ethernet,
linked by virtual point-to-point links called "tunnels". The tunnel endpoints are typically workstation-class
machines having operating system support for IP multicast and running the "mrouted" multicast routing
daemon.
Multicasting
To transmit a message to specific recipients across a network. A simple example of multicasting is sending
an e-mail message to a mailing list. Teleconferencing and videoconferencing also use multicasting, but
require more robust protocols and networks. Standards are being developed to support multicasting over a
TCP/IP network such as the Internet. These standards, IP Multicast and Mbone, will allow users to easily
join multicast groups. Note that multicasting refers to sending a message to a select group whereas
broadcasting refers to sending a message to everyone connected to a network. The terms multicast and
narrowcast are often used interchangeably, although narrowcast usually refers to the business model whereas
multicast refers to the actual technology used to transmit the data.
Multiplexing
A function within a layer that interleaves the information from multiple connections into one connection.
MUX
See "Multiplexing" on page 12.
N
NAT
See "Network Address Translation" on page 12.
netmask
Combined with the IP address, the IP Subnet Mask allows a device to know which other addresses are local
to it, and which must be reached through a gateway or router.
A number that explains which part of an IP address comprises the network address and which part is the host
address on that network. It can be expressed in dotted-decimal notation or as a number appended to the IP
address. For example, a 28-bit mask starting from the MSB can be shown as 255.255.255.192 or as /28
appended to the IP address.
Network Address Translation
Sometimes referred to as Transparent Proxying, IP Address Overloading, or IP Masquerading. Involves use
of a device called a Network Address Translator, which assigns a contrived, or logical, IP address and port
number to each node on an organization's internal network and passes packets using these assigned
addresses.
C-12 Glossary
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