Questions about mixing hubs and swtiches in a network...

[spoon805]

Short Version

If a switch is plugged into a hub, will it operate worse/same/better as if it was just the hub alone? Will it operate worse/same/better as if it was just a hub plugged into another hub?

Long Version

I have a very odd and rare case for you all. The goal is to decide what is the best solution for my scenario. As a newbie network guy, I may be asking really weird and dumb questions. I searced the forum, but nothing really came up with much. So here goes...

THE SITUATION
I've been building a small DSL-sharing network in my apartment complex using a Netgear RT314 (w/ integrated 4 Port switch) Router and various 10/100 NICs. Currently, one apartment (we'll call it apt. A) is the main "gateway". It has the DSL modem and the router. Additionally it has one PC plugged into the router. Another apartment (we'll call it apt B) has two PCs plugged into a 10mb hub that is uplinked to the router. However, the hosts in Apt. B have a poor connection to the router. Apt B is connected to apt A by a series of connection breaks and reconnections. (routerw/switch-> cable-> walljack-> cable-> walljack-> cable(outdoors)-> walljack-> cable-> walljack-> cable-> hub-> PC) With the 10mb hub, everything is fine. However, when the hub is removed and a PC (host) is directly connected cable that leads to the wall jack, this poor connection has made it impossible to connect at 100mb. Without the hub, the network only fully functions when the host's NIC is set at 10mb speed.

Now the story unfolds with even more complications. Apt B. is in plans to be a like a "subnet hub" for other hosts in other apartments in the complex. A swtich is arguably the best device for this. However, since all switches on the market are 10/100 auto sensing, I'm kinda screwed. Why? Well, one of the hosts in apt. B can connect at 100 mb, BUT all packets are eventually lost/dropped. Only when it is set at 10 mb will packets flow smoothy. Well, this problem cascades down to switches as well. We had a netgear 10/100 Autosensing switch. We placed this in Apt. B hoping it would connect succesfully at 10 mb. However, it attempted to connect at 100 mb and continually failed, rendering the switch useless.

THE QUESTION
In light of things, my new goal is to force the connection to 10 mb right after the router, before reaching Apt B. I am thinking about uplinking a 10Base Hub directly into the router (in Apt A.) and then uplinking a 10/100 switch in Apt. B into one of the ports of the hub.

Router(w/switch)-> 10Base Hub -> outside cable (with mutiple breaks and reconnections)-> switch -> 4-6 PCs (hosts)

Theoritically, I would have succesfully forced the line to 10 mb so the switch can now succsfully connect at 10 mb as well. However, I have a questions about possible design flaws.

How bad will the collisions be?
Could all hosts connected to the swtich enjoy a internet game of Counter Strike at once?
Would I just be better off with the following design? Would if be the same as?
Router-> outside cable (with mutiple breaks and reconnections)-> 10Base Hub -> 4-6 PCs (hosts)

If you read this far,..thanks...really...thanks... you've had to put up with my bad writing skills.

Please advise. Thanks in advance for any help.

 

[Garion]

The more half-duplex (hub) links you put in, the more delays you are going to create in your network. In your router -> 10M Hub -> 10/100Hub you're just adding hops and aren't really getting anything out of it. You would be much better to go straight from the router to a 10Mb hub.

If there's a PC with a problem NIC that won't connect, why don't you just spend $20 on a new NIC and get one that autodetects correctly? That would be far easier than trying to design around it.

One thing to keep in mind.. Your Internet connection is going to be WAY slower than a 10Mb/s hub link. You don't need to go out of your way to create a high-speed link to the router when that's just overkill.

If, however, you wanted to get maximum performance WITHIN your network (and all the apartments) you would be well off just going straight for switches and link them together. Should work fine and they are very cheap nowadays. (Assuming you swap the offending NIC).

- G

 

[spoon805]

<< If there's a PC with a problem NIC that won't connect, why don't you just spend $20 on a new NIC and get one that autodetects correctly? That would be far easier than trying to design around it >>



I wish it was just a NIC problem. I've tested this these lines with multiple laptops and desktops with nics ranging from Intel, Linksys, to Xircom... none of them can correctly detect the connection. Its definetly those wall jacks that are creating some screwed up shorting or something.

Many of you might wonder why i don't just redo the wall jacks and cabling... well, that's pretty time consuming, and I'd prefer just designing around that.

 

[spoon805]

from what people have told me today in person, I have come up with another question ...

If I use this design:

Router(with integrated 4 port switch) -> hub -> switch

... the switch should then succesfully drop connection speeds and link up at 10 mb

However, we all know that hubs broadcast to every address, right? Well, if the switch was the only device plugged into the port, would all the broadcasts go to that one port? And if so, would the switch then take over and broadcast the packets directly to the destination host?

 

[dowser]

Um, why not just buy a switch where you can change the port speed/duplex settings via software management?

Costs a bit more, but then anything using you're shoddy structured cabling (was it designed for data, or just voice, lol?!) can be set to 10/half operation.

Any uplink connections (hub-switch or switch-switch) should be 100/full (if they're needed. As should the routers connection to the LAN.

Broadcast traffic goes everywhere there's a valid connection into a hub or switch port - you're just talking about a flat L2 segment.....as long as there are no VLAN's set-up on your switches....but if there were then it means you've got s/w management and can change port settings

Good Luck
Richard

 

[Jhhnn]

Not like I'm some kind of Guru on the subject, but it seems to me that there's never been any solution to a cabling problem other than fixing the stuff, pure and simple. &quot;Designing around it&quot; is futile, pounding sand into a rathole, to use one of the nicer euphemisms that come to mind.

Reminds me of the people I work for at a public transit &quot;Maintenance Facility.&quot; They structure their thinking to maintain problems at a low level of functionality. If we were supposed to solve problems, it would be a &quot;Solution Facility,&quot; right?

 

[Zach]

I had the exact same problems with a line, a couple wires in one end of a cable were swapped. You could just fix your wire ends.. chances of the wires being bad is slim, you'd really have to mess up a cable. I've seen cables being bent through doorways, squashed by the door at every shutting into somethign 1/8&quot; high and 1/2&quot; wide, and still do fine at 100baseT. I soldered a splice into a cable, it runs fine (for me, it does about 50mbit, and I don't know what real world 100baseT should be). Assuming you are using real Cat5?

Other then that, use hubs to link the bad cables, they'll be forced to operate at 10/half. THen the good lines get direct connections to the switch, and plug the hubs into the switch.