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| cloclo 2004-05-11, 7:30 am |
| Hi all,
At work we have 4 floors and each floor is on a different subnet each separated by a swtitch and all 4 switches are connected to a router.(it think!)
Floor 1 is on 172.25.10.x
Floor 2 is on 172.25.20.x
Floor 3 is on 172.25.30.x
Florr 4 is on 172.25.40.x
/24
They refer to the above as Vlans. Sureley they are not vlans but just lans... Or have i got my big fat knickers in a big fat twist?
Thank you
PS: If i'm a total idiot, explain why as well | |
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| cloclo 2004-05-11, 1:04 pm |
| Hey darthfeces,
Tell me, have you ever read something and you still can't understand? Then you try and read from another source and you still can't understand? Then you go and ask someone...
If someone posts a question, i should hope that he or she has at least first done a bit of research and then take time to explain as opposed to throwing a book on his desk or telling him to google!!!
Thank you. | |
| darthfeces 2004-05-11, 1:16 pm |
| this should help ....
http://www.linktionary.com/v/vlan.html
http://www.networkmagazine.com/shar...ticleID=8702678
if you still don't get it maybe a basic understanding of internetworking is warranted ?
rather than imposing blame for the inability to grasp a concept?
N+ maybe ?
THE VLAN ARRIVES
As switches have become cheap and easy tools for segmenting flat networks, vendors have looked for ways for network managers to contain broadcasts without having to install routers on every segment. Virtual LANs, or VLANs, can best be thought of as logical broadcast domains, as opposed to the "physical" broadcast domains we have been discussing. Without VLANs, the traditional way to break up flat networks is to insert a router between the subnets you want to define. The IP addressing scheme supports subnetting in a way that many sites have managed to make work, though it would be hard to claim this method is flexible or easy to grasp. (NetWare networks are somewhat easier to configure as subnets because file servers with multiple network interfaces are routers by default.) | |
| cloclo 2004-05-11, 2:29 pm |
| Thank you darthfeces.
I passed N+ only 4 weeks ago and N+ does not go into internetworking a great deal and certainly not lan/vlan.
My question was:
...4 floors and each floor is on a different subnet each separated by a swtitch and all 4 switches are connected to a router.(I think!)
Floor 1 is on 172.25.10.x /24
Floor 2 is on 172.25.20.x /24
Floor 3 is on 172.25.30.x /24
Florr 4 is on 172.25.40.x /24
Are these vlans or just lans or not enough info? The question is pretty straight forward. (as straight forward as a yes or a no.)
When you learn something new you try and establish what environmetn you work in 10mbps,100mbps,ethernet star ring bus cat 5, cat3 lans vlans.
Get my drift, all i want is:
Yes the above scenario is 4 vlans or
No the above scenatio is 4 lans...
If you don't have enough info to establish if lans or vlans, then say so and tell me why
Thank you
PS: I am only just starting CCNA and i have not reached the VLAN chapter yet...
Say a student who is studying to become a doctor ask in his first year 2nd week, his lecturer the difference between a viral, a fungal and a bacterial infection.
- Surely you shoudl know that!
- No, this is my first year
- Ho sorry, i thought you were 5th year... | |
| forbesl 2004-05-11, 2:52 pm |
| quote:
Originally posted by cloclo
If you don't have enough info to establish if lans or vlans, then say so and tell me why
Thank you
Not enough information is given about your network topology. | |
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| forbesl 2004-05-11, 3:27 pm |
| quote:
Originally posted by cloclo
So what would be a good indicator as to wheather we are dealing with 4 lans or 4 vlans?
...your network topology (how your network devices are interconnected).... | |
| cloclo 2004-05-11, 3:36 pm |
| A switch on each floor. All computer on each floor connected to their switch and all 4 switches connected to either a router or daisy chained.... not sure! | |
| forbesl 2004-05-11, 4:27 pm |
| quote:
Originally posted by cloclo
A switch on each floor. All computer on each floor connected to their switch and all 4 switches connected to either a router or daisy chained.... not sure!
If you're not sure, no one can answer your question. The fact that you have four switches, one on each floor, with computers connected to them doesn't tell us anything. Are they daisy chained? Are they all connecting to one central switch on a single router interface? Are they connecting on separate router interfaces? Is the switch configured for separate VLANs? This is all part of your topology.
Have you asked any of your network techs or network admins at work the same question about VLANs? | |
| darthfeces 2004-05-11, 4:30 pm |
| if the hubs are physically seperate and each connected to a physical router port, then your network is flat.
if your switches are connected together by trunks (trunks carry vlan traffic)
then it's vlan's .....
if the network staff there is referring to vlans that i think that's a pretty big clue
you're working in a vlan enviornment. | |
| cloclo 2004-05-11, 6:24 pm |
| Thanks mate,
I am beginning to understand what vlans are about now.
No, i have not asked the people i work for because they are like me, they know jack crap. Yes they know jack crap. Why? because we don't maintain the the lan and wan and that's why i'm getting out.
Thank you. | |
| edmonds_robert 2004-05-11, 10:49 pm |
| A VLAN is not a physical thing, hence the "V" meaning "Virtual." A VLAN is a logically seperated LAN, rather than a physically seperated LAN. What this means is, a networking device (a switch) performs the seperation of the LANS, as opposed to actually physically seperating them by putting them on physically seperate, non-connected networks.
Without any layer 3 devices between them, VLANs would remain seperated, logically, permanently. Add a layer 3 device, (whether it is a layer 3 switch, or a router) configure routing between the VLANs, and they are no longer seperate.
What you have demonstrated, with the subnet addresses that you have listed, is a typical setup of IP subnets used to identify each VLAN. The layer 3 device on your network (which is surely present if these devices are able to talk to each other, or to servers on your network) performs the routing function between the devices on these VLANs.
Hopefully that clears things up a little for you. Good luck. | |
| cloclo 2004-05-12, 8:51 am |
| I have asked 2 of them.
1 tells me that they are vlans the other one tells me that they are not vlans but they could be configured as vlans.
I would have thought that if subnets are physically segregated (floor)and all computers on the same subnet connected to the same switch then they are not vlans but if you had say machines here and there at random places and connected to different switches on the same subnets then they could be vlans... | |
| HOOLIGAN 2004-05-14, 7:53 am |
| Its not that complicated. Think of it as breaking your switch up into a number of hubs. And these 'hubs' on your switch ( like real hubs ) are giving you four seperate LANS (virtual-LANS). Remember VLANs are a layer two concept and they are ignorant of IP packets and subnets. You need the router so the differnt lans can communicate with each other. | |
| Goldorak 2004-05-17, 2:32 pm |
| Hooligan says:
quote:
Think of it as breaking your switch up into a number of hubs. And these 'hubs' on your switch ( like real hubs ) are giving you four seperate LANS (virtual-LANS)
Hooligan,
Surely you are not turning your switch into, say, 4 hubs!(that would be a bit counter productive (i think!))
More like one switch seperated into 4, giving 4 virtual switches... | |
| HOOLIGAN 2004-05-19, 11:19 am |
| quote:
Originally posted by Goldorak
Hooligan says:
Hooligan,
Surely you are not turning your switch into, say, 4 hubs!(that would be a bit counter productive (i think!))
More like one switch seperated into 4, giving 4 virtual switches...
Of course not.
I Just gave as simple an answer as I could to emphasize that Vlans are used to create seperate Networks; LANS; broadcast domains or what ever you would like to call them.
But no, they are not broken up into hubs where I work. We have them configured into many more VLANS then four.Employing a whole range of interesting features found on CIsco switches. |
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