Link to home
Start Free TrialLog in
Avatar of anthony_hurley
anthony_hurleyFlag for United Kingdom of Great Britain and Northern Ireland

asked on

Guest VLAN using Netgear and Draytek

Hi all,

Please excuse my lack of knowledge here, but VLAN's are totally new to me.

I have the following hardware setup was using Windows 2008R2 as a DHCP server.

Draytek 2960 (GW) <-------> Netgear GS748TP <-----------> Netgear WNAP 320

I would like to add a wireless Guest network, however I totally confused in what I need to do to set this up. For example, does the main network (for employees) need to be a VLAN?

If any one could point me in the right direction it would be much appreciated.

Thanks
Anthony
Avatar of hypercube
hypercube
Flag of United States of America image

I'd recommend that you start with the question: "What is a VLAN?"  Then parse it to "Virtual Local Area Network" and then consider what does "Local Area Network" intend to mean?  

It's hard to find definitions which convey this notion that I find suitable.  So here is my own definition (while I take no credit for it).
"A Local Area Network" is an interconnected system of (generally) Ethernet cables which may be interconnected with layer 2 switches to extend and connect those cables.  It's a "copper" network.  By extension, it might include wireless links."
This is to be contrasted with the term "subnet" because one can carry multiple / distinct subnets on the same copper wires.

So, I would say that a *vritual* LAN or VLAN is one that will carry distinct and multiple subnets *as if* it were an interconnected distinct copper network.

Consider how a switch works:
The LAN ports are functionally all connected together.  If it's a smart switch then dynamic data paths are formed between switch ports (device MAC addresses) in order to increase switch total bandwidth and to avoid packet collisions.  This way, pairs of ports (and the computers connected to them) can communicate with each other without interference from traffic between other ports (computers).
Anyway, this idea of "connection" is a bit fuzzed up in a smart switch.
But, the idea of a smart switch rather helps us understand the idea of a VLAN implementation.
It's a way to segregate traffic.

Consider an 8-port Layer 2 switch.  It can handle the traffic of multiple subnets (even though in practice it usually doesn't handle more than one).  So, it's a reasonable component of a LAN.
Now consider that the switch is separated into two 4-port segments.  It's like having two separate switches in the same box.
One segment of ports handles a LAN.  The other segment of ports handles an entirely different LAN.  This is because the switch implements complete isolation between the two.  
Because the two LANs are supported in the same switch and are isolated (in firmware), we call these LANs "virtual".
And that can be pretty handy.

Further, using networking conventions, these VLANs can be handled in bundles by use of packet tagging.  But I think that's beyond your concern right now.

Another perspective is that you never need to use VLANs at all if you are content with simply adding physical LANs.  
This brings up another important topic:  "How do VLANs get connected to other VLANs or the internet?"

Imagine a simple network, without an internet gateway at all, and we want to communicate between LANs.
In this case we could add a router as an inter-LAN gateway which would route packets between the two.
Similarly, we could use a router as an internet gateway:

Here is a simple text diagram of a 2-LAN network with an internet gateway.

LAN1 <> LAN Router <> LAN2 <> Internet Gateway Router.

Here, the LAN router provides inter-LAN connectivity and provides LAN1 with a path to the internet via LAN2.
There are only physical LANs here, no VLANs - and the internet traffic for LAN2 flows through LAN1.

Here's another:

LAN1 <> Internet Gateway Router <> LAN2

In this case we have to assume that the Internet Gateway Router is capable of handling 2 LANs on separate ports.  Some such routers *will* call these VLANs and that's OK as long as we understand that they really are just separate LANs.  Well, that model works until one uses more advanced capabilities.  And, in this case we can assume that the Internet Router is capable of routing between the LANs just as was accomplished in the first case.  But here the LAN1 internet traffic no longer flows through LAN2 wires.

But, most often, a router won't have enough ports.  So we need to add a switch.
If we don't use VLAN capabilities then we'd use two switches; one for each LAN.

LAN1 <> Switch1 <> Internet Router LAN1port(s)
LAN2 <> Switch2 <> Internet Router LAN2 port(s)

But, if we *do* use VLAN capabilities, we could do the same thing in a single switch like this:

LAN1 <> Switch1 VLAN1 ports <> Internet Router LAN1port(s)
LAN2 <> Switch1 VLAN2 ports <> Internet Router LAN2 port(s)
[note that there is now only Switch1 and it's ports are separated into 2 VLANs.  And there are still 2 wires going to the router.]

As you work with various different equipments, the terminology will vary a bit and the capabilities will certainly vary.  But this is a quick overview of what VLANs are and aren't.....

I hope this helps.
ASKER CERTIFIED SOLUTION
Avatar of Frosty555
Frosty555
Flag of Canada image

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
SOLUTION
Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
Avatar of anthony_hurley

ASKER

Guys,

Many thanks for your detailed explanations. Whilst this confirmed my understanding of VLAN's, I find  implementing of them is a different thing. Unfortunately I only had a limited time to test/implement, therefore I will revisit this during my next visit in July.  

Many thanks for your help.