Subnetting Vs VLAN

yama_palla

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Dec 5, 2010
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___Narakadiya___
hey guys.i want sum clarifications about above two words.

01 What is main difference between Subnetting and VLAN ?
02 What are advantages of subnetting ?


Help me, if u know please.thanks.
 

navodth

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Nov 29, 2006
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Negombo
Subnets are subdivisions of a Class A, B, or C network. They allow a single Class A, B, or C network to be used instead of multiple networks.

VLAN's are simply devices that are connected logically rather than physically (either through the port they are connected to or their MAC address).

The way VLANS communicate depends on a couple of different things. If multiple devices are in the same VLAN and are on the same switch, Layer 2 switching occurs, which pretty much means the switch handles it. If one device on one switch needs to communicate with another device on a separate switch (and they are in the same VLAN), a trunking protocol is used (ISL or 802.1q). This simply adds an extra piece to the header that clarifies what the VLAN ID is.

Now, if a device on VLAN A needs to talk to a device on VLAN B, a router or a layer 3 switch is needed (a switch with built in routing features).

VLANs are useful for administrative ease, security, reduced broadcasts, and to separate specialized traffic from each other (by department, group, etc)


Source - http://www.proprofs.com/forums/index.php?showtopic=4452
 

::neXGen::

Well-known member
  • Jun 24, 2010
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    1. The major difference is that joining a subnet is based on client side IP configuration. Therefore the client can use any subnet he wants. For a VLAN the configuration is done on server side (e.g. based on LAN port) and the client can not change it. From a security perspective this is a big difference.
    ______________________________
    2.

    advantages are:
    1. Security – A particular subnet might only need access to a limited number of network resources. Another part might only need access to a local workgroup.
    2. Performance – A particular subnet might need to have higher network priority than others. For example, a Sales department might need to host web casts or video conferences.
    3. Establish a DMZ – Many companies house their own web server. Subnetting would allow a company to create a subnet that would send/receive web server traffic, but nothing else.
    disadvantages are:
    1. Costs – Reliable network equipment such as routers, switches, hubs, bridges, etc are very pricey. They have come down in price over the last few years, but the good stuff is still expensive.
    2. Support – Subnetting and network management in general requires an experienced network administrator. This adds to the overall cost as well. The average salary of a network administrator in the Sacramento area is $60,000 per year.
     

    ins

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    Dec 21, 2006
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    SUBNETTING-
    its to divide an ip block(class a,b,c ..) into smaller networks.the reason to subnet is
    because a router or a network device can only hold onto less than 500 hosts(PCs).more than 500 hosts create heavy load and the routing will be effected due to high traffic.
    so for an class A address there are thousands of free addresses (10.0.0.0 -10.255.255.255.)and a router only can work with 500,so teh rest addresses are wasted..we can subnet the ip address and use it efficiently without wasting valuable ip adresses.

    its like separating an ip block like class A,B,C logically.

    vlan-
    its done in switches.each Vlan have be be assigned into different subnets,
    a switch is a broadcast device,and its not very secure coz when a pc Asends a message to another pcB,all pcs which are conected into every port inthat switch gets the message pcA a sent.but only pc b will open since its derected to pcb.so nothing in a switched environment is private
    and company may have several departments, like accounts,hr,managements etc..and each dept must be private.or the company can fall into huge trouble.so there are two options..the company can have a switch per deptartment so tyhat it will have 3 different switches (very expensive and a silly step)or it can use VLAN(very cost effective)

    vlans logically breaks up the switch into different switches,so a switcg can have many vlans which would act as many switched
    eg- 3 vlan=3 switches but actally its done in 1 switch
     

    dole

    Active member
  • Jun 1, 2008
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    එක එක තැන
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    yama_palla

    Member
    Dec 5, 2010
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    ___Narakadiya___
    SUBNETTING-
    its to divide an ip block(class a,b,c ..) into smaller networks.the reason to subnet is
    because a router or a network device can only hold onto less than 500 hosts(PCs).more than 500 hosts create heavy load and the routing will be effected due to high traffic.
    so for an class A address there are thousands of free addresses (10.0.0.0 -10.255.255.255.)and a router only can work with 500,so teh rest addresses are wasted..we can subnet the ip address and use it efficiently without wasting valuable ip adresses.

    its like separating an ip block like class A,B,C logically.

    vlan-
    its done in switches.each Vlan have be be assigned into different subnets,
    a switch is a broadcast device,and its not very secure coz when a pc Asends a message to another pcB,all pcs which are conected into every port inthat switch gets the message pcA a sent.but only pc b will open since its derected to pcb.so nothing in a switched environment is private
    and company may have several departments, like accounts,hr,managements etc..and each dept must be private.or the company can fall into huge trouble.so there are two options..the company can have a switch per deptartment so tyhat it will have 3 different switches (very expensive and a silly step)or it can use VLAN(very cost effective)

    vlans logically breaks up the switch into different switches,so a switcg can have many vlans which would act as many switched
    eg- 3 vlan=3 switches but actally its done in 1 switch
    1. The major difference is that joining a subnet is based on client side IP configuration. Therefore the client can use any subnet he wants. For a VLAN the configuration is done on server side (e.g. based on LAN port) and the client can not change it. From a security perspective this is a big difference.
    ______________________________
    2.

    advantages are:
    1. Security – A particular subnet might only need access to a limited number of network resources. Another part might only need access to a local workgroup.
    2. Performance – A particular subnet might need to have higher network priority than others. For example, a Sales department might need to host web casts or video conferences.
    3. Establish a DMZ – Many companies house their own web server. Subnetting would allow a company to create a subnet that would send/receive web server traffic, but nothing else.
    disadvantages are:
    1. Costs – Reliable network equipment such as routers, switches, hubs, bridges, etc are very pricey. They have come down in price over the last few years, but the good stuff is still expensive.
    2. Support – Subnetting and network management in general requires an experienced network administrator. This adds to the overall cost as well. The average salary of a network administrator in the Sacramento area is $60,000 per year.
    Subnets are subdivisions of a Class A, B, or C network. They allow a single Class A, B, or C network to be used instead of multiple networks.

    VLAN's are simply devices that are connected logically rather than physically (either through the port they are connected to or their MAC address).

    The way VLANS communicate depends on a couple of different things. If multiple devices are in the same VLAN and are on the same switch, Layer 2 switching occurs, which pretty much means the switch handles it. If one device on one switch needs to communicate with another device on a separate switch (and they are in the same VLAN), a trunking protocol is used (ISL or 802.1q). This simply adds an extra piece to the header that clarifies what the VLAN ID is.

    Now, if a device on VLAN A needs to talk to a device on VLAN B, a router or a layer 3 switch is needed (a switch with built in routing features).

    VLANs are useful for administrative ease, security, reduced broadcasts, and to separate specialized traffic from each other (by department, group, etc)


    Source - http://www.proprofs.com/forums/index.php?showtopic=4452


    All answers helped to solve my mind.thank u guys.
     

    ins

    Member
    Dec 21, 2006
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    An 1 more thing.Is subnetted networks can communicate with each others.i know,its impossible in the VLAN's.

    both subnetetd and vlan networks can communicate only if there is a layer 3 device which is a router or a layer 3 switch.

    for vlan connectivity its called router on a stick and subnetting connectivity is called routing

    no router=no routing(no communication above the network).