RTS EKP-632 User Manual page 105

Network Terminology
Bridges
- A bridge is a device that connects two LANs, or two segments of the same LAN that use the
same protocol. Sometimes called "transparent bridges", they work at the OSI model Layer 2.
Simply put, they are not concerned with protocols. Their main job is to pass data to a destina-
tion address that is predetermined in the data packet.
With a bridge, all you computers are on the same network subnet (see Subnet). This means
your computers can communicate with each other and have their own Internet connection. If
you assign your own IP Addresses be sure to use the same first 3 "octets" of the IP Address
(for example, 192.168.0.X).
Domain
Name Server
- A DNS Server is an Internet service that translates domain names (for example, in the URL
http://www.telex.com, the domain name is telex.com) into IP Addresses. The Internet is based
on IP Addresses which are numeric and since domain names are alphabetic, they are easier
to remember. Everytime a domain name is used it must go through the DNS server to be
translated into an IP Address.
Gateway
- A gateway is a node on a network that serves as an entrance to another network. The
gateway routes traffic from a computer to an outside network that is serving the web pages.
For example, the gateway for a home computer is the ISP provider that connects the user to
the Internet.
In a corporate environment, the gateway often acts as a proxy server and a firewall. Gate-
ways are similar to routers and switches in that they forward data to the destination and
provide the path for which the data will travel to the destination.
Hub
- A hub is a common connection point for devices in a network. A hub has multiple ports.
When a data packet arrives at a hub it is copied and distributed to all of its ports so that all
nodes on the LAN can see the packets.
These are three types of hubs:
passive hub : this hub serves as a conduit for the data, enabling it to go from one
device to another.
intelligent hub (also known as manageable hubs) : this hub includes additional fea
tures that enable administrators to monitor traffic through the hub.
switching hub : this hub reads the destination address of each packet and then
forwards the data packet to the appropriate port.
IP Address
(Internet
Protocol)
- An IP Address is an identifier or numerical name for a computer or device on a network. Data
between computers is routed over the network using these addresses to identify the computer
the message is being sent to and from.
The format of an IP address is a 32-bit numeric address written as four numbers separated by
periods. For example, an IP Address looks like 10.100.1.1.
Important: When working within an isolated network (meaning there is no Internet access), IP
addresses can be assigned at random just as long as they are unique to each computer and
device.
The four numbers in an IP address are used in different ways to identify a particular network
and host on that network. There are three classes of Internet addresses:
Class A - supports 16 million hosts on each of 127 networks.
Class B - supports 65,000 hosts on each of 16,000 networks.
Class C - supports 254 hosts on each of 2 million networks.
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