Hybrid meshed network topology

[sandrock]

I am hosting a 100+ person lan party in October and am trying to finalize a network topology.

I will have 5 nodes of 24 people each. Each node will have a 24 port switch w/ 2 gigabit uplinks (D-Link DES-1026G - Newegg Link (http://www.newegg.com/app/ViewProductDesc.asp?description=17-111-014&depa=1) )

For the backbone, we have two full gigabit switches, the first is an 8-port (Netgear GS108 - Newegg Link (http://www.newegg.com/app/ViewProductDesc.asp?description=33-122-111&depa=1))
The other is a 5-port (Intellinet Desktop Gigabit - Product Link (http://www.intellinet-network.com/html/522298.htm))

Normally, we use the 8-port netgear as the backbone switch in a star topology, and just use the 5-port as a staff gigabit switch.

http://gblan.com/ki/multimedia/starnetwork.jpg

But I figured, can't we use both gigabit uplink ports on the 24 port switches, and just hook them up to each gigabit switch respectively?

http://gblan.com/ki/multimedia/meshnetwork.jpg

This should add a bit of speed and redundancy as well, correct? What does everyone think of this setup for a 100+ person lan party?

The next step is management :attn:

[XWRed1]

Hooking up both gig switches wouldn't accomplish anything I don't think.

Think about it. Say the blue switches are marked 1 through 5. If a port on switch 2 wants to talk to a port on switch 4, what path does it take? Its ambiguous.. could take either one. It probably doesn't know which gig switch is least loaded, you need smart switches for that.

At best it'd be as if there was only one gig switch hooked up, at worst they would interfere with each other. Or I could be confused.

[Xenocide]

well in wisconsin we are having a lan in october also, ~150+ people i think. gonna be october second,

[sandrock]

Wouldn't happen to be Midwest Lan in Waukesha? I'm running Kick It Lan up in Green Bay. Funny coincidence there :)

[Xenocide]

yea its midwest lan :)

[su root]

That setup won't work, it will end up in broadcast storms. (if you need the technical reason why, ask and I'll explain it)

If you are looking for a non-blocking solution (where no one will suffer bandwidth loss because the network's uplink ports are busy), then you will need 10gigabit uplinks. (Expensive)

Another solution is to get equipment that has Channel Bonding (aka Etherchannel), which will allow you to connect 2 links between the switches that acts like one 2Gig link. However, with 24 hosts on each, it's still blocking. (switch can create a max of 2.4gigs of traffic, while the uplink can only handle 2gigs)

You can also do it with 3 channels bonded, which is non-blocking, but rarely do you find a switch with that.

Personally, I don't think you will have a problem with the 1gig uplink setup. Games don't take up that much bandwidth, and there will always be people sitting out, or playing games, and thus not using their full 100mbits.

[sandrock]

I should mention, I only have one of the D-Link switches currently. We were planning on purchasing the remainder shortly before the event to finalize the network. After seeing some responses here, and doing some research, I think we would be better off not getting the D-Link switches.

su root, I believe I've heard of channel bonding before. Would this be the same concept as trunking? If so, the TrendNet TEG-2224WS (http://www.newegg.com/app/ViewProductDesc.asp?description=17-111-473&depa=0) says it supports trunking. And for nearly the same price as the 'dumb' D-Link switches, I think those would be a much better buy. Even if we cant use the trunking for this lan, we can get a new 16-port gigabit switch for the backbone that supports trunking for our next lan event.

I agree with you, we should be fine with just a single gigabit backbone, but we have access to two gigabit ports, so naturally I want to take advantage of both. ;)

Continuing on, I've been reading about the concept of the spanning-trees protocol (802.1d). I found an interesting article on How Stuff Works (http://computer.howstuffworks.com/lan-switch14.htm). I don't suppose this is something any of these switches could handle.

[su root]

Trunking is not the same as Channel Bonding. Trunking allows multiple VLANs (Virtual Lans) to travel through a single port. VLANning a Lan Party switch is not a great idea.

I personally have never had any problems with my D-Link switch (it's a consumer 8-port switch though).

Spanning tree will run on the DES-1026G, but wasn't mentioned on any of the others. Which means it's fairly useless if only one switch supports it. For a Lan Party, it's fairly redundant anyway. It provides loop-free failover links between switches.

[sandrock]

Ok, so the D-Link switches I was originally planning on buying support spanning tree. And according to that article I linked to:

Essentially, a spanning tree uses the spanning-tree algorithm (STA), which senses that the switch has more than one way to communicate with a node, determines which way is best and blocks out the other path(s). The cool thing is that it keeps track of the other path(s), just in case the primary path is unavailable.

So, in theory, my setup going to two switches should work if I go with the D-Link switches that support spanning tree. Blue being the d-link switches

http://gblan.com/ki/multimedia/meshnetwork.jpg

Each d-link switch will see there is two possible routes it could take. It would calculate the best route and block the other path. So theoretically, it should use both lines simultaneously (someone is using ~60mbit on one line, it would see the other is not as congested as use that for the next user). It should also provide redundancy should one link go down, but without creating any loops and avoiding a broadcast storm, which would majorly congest the network. Does that sound about right?

Now what about the two backbone switches. As far as they are concerned, each switch only sees the 5 D-Link switches. The two backbone switches aren't connected together. So I shouldn't need spanning tree on the backbone switches.

I will be testing all of this before the lan anyways, I'm just trying to find out possible configurations and what to expect. :cool:

[su root]

Close, but no cigar.

You need the Red and green switches to also support STP. If they don't, then you'll just get broadcast loops.

When STP is running, it choses a "Root Bridge", which is one switch on the network that every switch should have one, and only one path to. In this situation, the red switch is the root switch:
http://ocimg.blackpacket.net/sandrock.jpg
As you can see, it will shut down all the links that will cause loops, basically turning off your 2nd switch.

In another scenario, say one of the dlinks gets chosen:
http://ocimg.blackpacket.net/sandrock2.jpg
In this case, some switches have chosen to use the red switch, while others have chosen the green one as their path to the root bridge. (Note that from each switch, there is only one path to the root bridge. In this case, traffic that wants to go from the far left D-link switch to the far right d-link switch will have to go to the red one, then through the root switch, then to the green one, then finally to the other switch. This means the links at the root switch will get overloaded.

Now, the neat thing about STP is that, in the last diagram, should the green switch die for some reason, the red one will take over all the connections, providing a path to the root bridge.

There is no need for STP at a LAN Party.