VLAN config Newbie

[HodgeHi]

Hello All,

 

I am dipping my toe in to plan configuration. I think i sort of know how they work but am now starting to configure them and struggling to work out the requirements for that network side of things. Let me try and explain further:

 

I have a single layer 3 switch (Neatgear) and would like to set up perhaps 3 VLANs for testing.

I configure the switch with an IP address of 192.168.0.200

I have a Virgin Media internet connection on 192.168.0.1

I configure the 3 vlans with IDs 3 (Server) IP range 192.168 0.0/24, 4 (Staff) IP range 192.168.1.0/24 and 5 (Students) IP range 192.168.2.0/24.

I then assign the ports to the VLANs (pts 1-5 = VLAN3), Pts 6-10 = VLAN4, pts 11-15 VLAN5)

When I go to set the VLAN routes, this is where I get confused. I configure default gateway for the staff as 192.168.1.1/24 and the students is 192.168.2.1/24 But since the switch is on the same subnet range as the server VLAN it says there is an overlap since it already exists as a default route.

 

So my question is how is the ip addressing configured to get this all working? I have gone through the manual but it never states how he switch IP addressing is configured. Is it in the default network range as the server, or the default gateway and so the rest need to be on different subnets. Will the default route carry the data anyway even if it has not been set.

 

I probably have many more questions but my brain is a bit bamboozled at the moment. I am probably over-thinking it but cannot get my head around the way it needs to be configured to allow me to think about how it all works together.

 

My understanding is that each plan needs to have a default gateway set so that the switch can route the data between them, which means that the server VLAN will also need a default gateway too?

 

If you need any more info to help then please let me know.

 

Thanks all.

[lostsoul]

It looks like you are nearly there. You could change the gateway of your server vlan to the last usable address of the subnet, to stop the conflict. For tidiness you could change the other vlans to use the same convention.

 

After that, as long forwarding is enabled you should be good to go.

[HodgeHi]

Thanks for the reply lostssoul. Since my original post I have shifted the default gateways for all VLANS over to .250 and created a 10.0.0.0/24 network for the switch management. This seems to resolve most setup issues I think. I have now just got to work out how to set a DHCP relay so I can get an IP on the other VLANs

[lostsoul]

Glad you've made some progress. DHCP helper should be easy to set up, you are simply telling the switch the ip address of your dhcp server, so it can forward requests from other subnets. Stick with it, VLANS are actually much simpler that you think.

[HodgeHi]

Hi I'm back,

 

I think I spoke too soon when I said i think I'm making progress. I cannot ping any gateway addresses (even when connected directly to a port on that VLAN). It must be something that Im doing wrong, although I find the manual on how to do this for the switch next to useless. Burning it might be a more useful purpose if it wasn't a PDF. I think it is the routing and VLAN interfaces that aren't working as they should but I don't know enough about VLANs or the way in which this switch is configured to work it out.

 

I have looked at forum posts online relating to an M4100 switch but this is a M5300 series. I assume that the process is the same but I don't understand what the documentation is doing to follow it with any idea as to whats going on.

 

I think I just need to know:

 

A) Do the ports need to be set to T (tagged) or U (Untagged). I have removed the U from the ports for VLAN 1. Is this right?

B) Routing. The guide goes through every kind of routing one after the other. So I don't know which one is supposed to do what I need. Is VLAN routing enough or do I need to enable RIP as well?

C) Do I specify that the Acceptable Frame types is Admit All or VLAN only?

D) Do I need to specify an IP address on the port interfaces for the Gateway addresses as well, or is this done through the VLAN virtual interfaces.

 

I'm ranting a bit now but I've been banging my head at this for over 2 weeks now and am ready to just forget it completely.

 

Hope someone can save the remaining hair on my head.

 

TIA.

[lostsoul]

Don't worry, I went through similar when I was learning.

 

A) you want untagged, it means any untagged frame that enters the port belongs to the vlan that you have set as untagged on that port. Think of it like this, you want to plug a pc into that port, the pc has no knowledge of what vlan it is going to be on. The frames coming from the pc will not have vlan data. I.e. It will be untagged. You have configured the switch so that untagged frames coming in on that port will belong to the untagged vlan. You can only have one untagged vlan per port.

 

Setting a tagged vlan on a port is for devices that are able to understand tagging. Things like VoIP phones, access points, nics on virtual hosts where virtual machines need to be on different vlans, and vlan trunks between switches. For example when you first plug in a phone, it might initially connect to the untagged vlan, the dhcp server may be configured to detect the phone and send back details of the vlan it should be on. The phone then connects to the tagged voice vlan. You can have many tagged vlans configured on a port.

 

B) I don't know that brand of switch, but basic vlan routing should be fine. Turn rip off.

 

C) I think you want admit all, otherwise untagged frames will be dropped..

 

D) the ip that you give the vlan on your layer 3 device, Is normally the address that is then used for routing once you have enabled it. The ip is set once per vlan. When you configure your client the default gateway is the address you gave the vlan on your switch. Don't use the Virgin media router address, that would probably work for getting the Internet on your server vlan, but not on the others, and routing between vlans would not work. With the default gateway on your client set to the vlan address on the switch, traffic not destined for the local subnet will be sent to the routing interface for the vlan. If the switch does not have knowledge of a local destination to send the packet, it will use the default route, which I hope you have set on your switch as you Virgin media router. If the switch knows the network, it will send it out of the interface for the appropriate vlan.

 

I hope someone can explain better that me, I'm a very visual thinker, what is clear in my head is surprisingly hard to put into words.

 

It's not just vlan theory you need, you need a basic understanding of how routing works too.

 

Good luck.

Edited May 26, 2015 by lostsoul

[HodgeHi]

Lostsoul,

 

Thanks for all your time and patience with this matter. You (and I) would be pleased to know that with your help I now have a fully functioning layer 3 switch with 3 VLANS and dhcp relayed IP assignment.

 

Once again thanks for all your help. You are testament to why this site goes from strength to strength. Enjoy your day and the rest of the week.

 

May the sun shine upon you always (too much?) 😊

[lostsoul]

Great stuff, glad you got it working.