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VLAN Justifications for a LAN Newbie

                   All,

All,

I know the need for vlans for voice and data and usually for wireless.  Can someone give me some insight on what the need might be to have separate VLANS for servers, PCs and printers as well?  I'm not sure if thre is a performance gain or some other "general" justification.  I'm sure that each network is different but just loking for high level opinion/best practice.

Thanks in advance!  Replies rated.

5 REPLIES
Super Bronze

Re: VLAN Justifications for a LAN Newbie

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Basically the same reasons; either for performance and/or security.  There's another, though, as servers and/or printers often have static IPs.  If you mix static IPs within a subnet also supporting dynamic IPs, the statics can be an issue if you want to resize/migrate the subnet for the dynamics.

New Member

Re: VLAN Justifications for a LAN Newbie

Thanks.  I know wireless is due at least in part to  security issuesCan you tell me what the performance gain might be if we separate servers and PCs into their own VLANs?

Re: VLAN Justifications for a LAN Newbie

"Can you tell me what the performance gain might be if we separate servers and PCs into their own VLANs?"

Depending on the size of your flat network (all in the same vlan), you may see no improvement at all. The advantage of separating them though is address management. It would be easier to maintain a user pc vlan, printer, and server vlan. Each vlan are their own broadcast domain, so heavy broadcast/multicast traffic shouldn't affect the server vlan if it's coming from the pc vlan etc.

HTH,
John

*** Please rate all useful posts ***

HTH, John *** Please rate all useful posts ***
Hall of Fame Super Blue

VLAN Justifications for a LAN Newbie

Scott

The other issue which is related to security somewhat is if a client NIC is faulty for example and starts flooding the vlan with broadcasts etc. it does not affect the servers or other clients in different vlans because broadcasts are contained within vlans.

Jon

Super Bronze

Re: VLAN Justifications for a LAN Newbie

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

As John and Jon have already described, VLANs often allow for smaller broadcast domain but besides broadcasts, if your have multicast, and your switches don't support IGMP snooping, VLANs might contain their traffic too.

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