• 11/17/2015
    8:30 AM
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VLAN Implementation Guide: The Basics

Virtual LANs are core to enterprise networking. This guide covers VLAN trunks, VLAN planning, and basic VLAN configuration.



Hi Andrew -- Thanks for this great guide! I'm curious if there's a common misstep that organizations make when it comes to VLANs? Is there a basic concept that gets overlooked?


Hi Marcia - The most common mistep that I come across is poor VLAN planning. Make sure you have a sound VLAN strategy for segmenting users/servers/wireless/guests etc into separate VLANs. This strategy should work well for future growth and any mergers/acquisitions.


Good one, adding little more to blog about LAN switching...

Hub can only work in half duplex mode for its need to replicate the electrical signal received on port x on all other ports.
This should be the only effect of the introduction of an hub between two switches.
Hub works at OSI layer 1 and it doesn't know what is the difference between: an Ethernet frame, an ISL frame or an 802.1Q tagged Ethernet frame.
Having an half duplex trunk is something to be avoided for performance and stability reasons.
Connecting multiple switches to an hub would be again a performance and a stability problem defeating MAC address filtering capability of switches.


@virsingh211 -- Thanks for adding some additional depth to the explaination of a hub. Much appreciated.

Andrew and The Community: VLAN Confusion Please Help !

Hi Andrew - 

Please help me understand this.  I have recently been entrusted with a network with no true DC, and the workstations are getting their IP's as soon as they hit the network through DHCP.

I have found that the router seems to be pushing these out even though I have yet to understand how they were entered.

Is this type of setup considered a VLAN ?

Re: Andrew and The Community: VLAN Confusion Please Help !

Routers can be setup to operate as DHCP servers. If you can login to the router, you should be able to see this configuration, make changes, or disable it, if you want.

Re: Andrew and The Community: VLAN Confusion Please Help !

@Andrew   Thanks !   I am discovering that as we speak, this is the first network I have ever seen constructed this way.   

I must say though the router approach seems to be more stable than the traditional DC approach.

Learn something everyday ( or at least one should).