TOPEX Bytton (HSPA+ / LTE)
ByttonLTE(full)_genericUsermanual_sw306FAS_revN.1.docx
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Why use VLANs?
- to minimize the broadcast domain. Broadcasts are required for the normal function of a network. Many
protocols and applications depend on broadcast communication to function properly.
But certain network devices will send out large amounts of broadcast traffic that can really slow down the
network, especially when it reaches a certain size, usually 600 devices or more. A layer 2 switched
network is in a single broadcast domain and the broadcasts can reach the network segments which are so
far where a particular broadcast has no scope and consume available network bandwidth. A layer 3
device (typically a router) is used to segment a broadcast domain.
VLANs may be used to segment a network, thus limiting the amount of broadcast: by segmenting a large
LAN to smaller VLANs, the broadcast traffic will / can be reduced as each broadcast will be sent on to
the relevant VLAN only. With VLAN, there will be less ARP messages and broadcasts!
- for Security. VLANs can be used as a security device to prevent specific hosts from seeing other hosts.
The VLAN technique may help to restrict sensitive traffic originating from an enterprise department within
itself. In a VLAN network environment, with multiple broadcast domains, the network Administrators have
control over each port and user. Now malicious user can no longer just plug their workstation into any
switch port and sniff the network traffic using a packet sniffer. The network administrator controls each
port and whatever resources it is allowed to use. Usage of VLAN means an increase in security, since the
information is encapsulated in an additional level and possibly analyzed.
VLANs can separate traffic logically within a switch or station, son one VLAN can not communicate
directly with stations on another VLAN. You can may also restrict which are allowed to communicate with
other VLANs, thus improving security. For instance, you could set up a guest VLAN that only allows
access to the Internet, not to other machines in the local network. Another “VoIP phone VLAN” may be
created especially for IP phones only. Generally, inside a company, different sections, departments,
buildings, floors, or even individual computers may be set up into their own networks, as large pr small as
really required!
- Much greater flexibility in usage and more flexibility in administration.
Use
: A VLAN has the same attributes as a physical local area network (LAN), but it allows for end stations
to be grouped together even if they are not located on the same network switch or even in the same
building. To physically replicate the functions of a VLAN, it would be necessary to install a separate,
parallel collection of network cables and equipment which are kept separate from the primary network.
Compared to this hardware approach, when you use VLANs, a new logical subgroup within a local area
network may be simply created via software, fast and with low costs, instead of manually moving Ethernet
cables in the network switches.
Since Virtual LANs are location-independent, the VLAN of a certain department may be all over the
building. Users can move to another office or another building while remaining in the same LAN.
One of the greatest advantages of VLANs is precisely this: when a computer is physically moved to
another location, it can remain logically in the same VLAN without any need for hardware reconfiguration.
Management
: LAN membership is easily defined by the network manager. All modifications to the
network are easier to perform, since all the architecture can be changed by simple parametering of the
switches via the Web configuration interface of Bytton.
VLAN membership can be configured through software instead of physically relocating devices or
connections.
- Costs: Any software implementation is cheaper than its hardware counterpart. Segmenting a large VLAN
to smaller VLANs costs less than creating a routed network with routers because normally routers are
more expensive than simple switches!
Also, since traffic between different LANs is routed, it is better to keep all traffic in a single LAN and avoid
WAN links, which are expensive!
