VM600 networking manual MAVM600-NET/E 1 - 9
Edition 9 - February 2018
Some networking terms and definitions
VM600 NETWORKING INTRODUCTION AND OVERVIEW
1.4.2 Connectivity within networks
The following devices may be found in networks (see also Figure 1-3):
1- Hubs
A hub is a common connection point for devices in a network. Hubs are commonly used
to connect segments of a LAN. A hub contains multiple ports. When a packet arrives at
one port, it is copied to the other ports so that all segments of the LAN can see all
packets.
The availability of low-priced network switches has largely made hubs obsolete but they
are still seen in older installations and more specialised applications.
2- Network switches
A network switch is a network device that cross-connects clients, servers and other
network devices. Also known as a frame switch, stand-alone LAN switches are common
in all Ethernet networks. A four-port switch is typically built into wired and wireless routers
for homes and small offices.
3- Routers
A router is a network device that forwards packets from one network to another. Based
on internal routing tables, routers read each incoming packet and decide how best to
forward it.
Most routers in homes and small offices do nothing more than direct Web, email and
other Internet transactions from the local network to the cable or DSL modem, which is
connected to an internet service provider and then to the Internet.
In larger companies, routers are also used to separate local area networks (LANs) into
sub networks (or subnets) for network management reasons. For example, in order to
balance traffic within workgroups or to filter traffic for security purposes.
4- Gateways
In computer networking, a gateway is a node on a network that serves as an access point
to another network. That is, a it acts as a go-between (entry/exit point) for networks or
subnets using the same protocols. (A router can be considered a special type of
gateway.)
The default gateway is a node on a network that is used when an IP address does not
match any other routes in the routing table. That is, a default gateway typically connects
internal networks and outside networks (for example, the Internet). See 5.5 Gateways
and 5.6 Adding a default gateway to a CPUM card for additional information.
NOTE: A network gateway, also known as a protocol translation/mapping convertor,
is a different device that converts packets from one protocol to another. That
is, a network gateway connects networks with different network protocol
technologies by performing the required protocol conversions.
5- Firewalls
A firewall allows or blocks traffic in and out of a private network or a user's computer.
Firewalls are widely used to give users secure access to the Internet as well as to
separate a company's public Web server from its internal network. Firewalls are also
used to keep internal network segments secure. For example, the accounting network
might be vulnerable to snooping from within an organisation.
In homes, a personal firewall is typically software that is installed on the user's computer.
In larger organisations, a firewall can be software in a router or server, or a stand-alone
machine. It can be as simple as a single router that filters out unwanted packets, or it may
comprise a combination of routers and servers each performing a specific type of firewall
processing.
To Next Page
Loading...
Need help?
General
