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/ 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. (router w/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/ intgrated 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.


[Edited by spoon805 on 06-26-2001 at 12:19 AM]

[clutchy]

i didn't read your whole post but basically i was just reading about this and the only diff between a hub and a switch is that a switch sends the info to a specific destination whereas a hub sends it to everything that is connected to it. switches are better but they do the same thing.

[Jeffbx]

You really want to go Router ==> switch ==> hub for the best connection. The switch can decide where traffic needs to go rather than broadcasting it everywhere. The more hubs you have (especially in a single subnet) the more collisions you'll have. You can avoid a majority of this traffic by making the switch the center of the network.

You're probably getting too much interference from somewhere - likely the outside cable. Can you replace it with a shielded, continuous wire?

Also, have you considered setting the NICs to 10Mb rather than the switch? You can also try setting them to half duplex rather than full. Or really simplify - dust off some old 10Mb NICs & plug them in....

[spoon805]

Originally posted by Jeffbx
You're probably getting too much interference from somewhere - likely the outside cable. Can you replace it with a shielded, continuous wire?

Also, have you considered setting the NICs to 10Mb rather than the switch? You can also try setting them to half duplex rather than full. Or really simplify - dust off some old 10Mb NICs & plug them in....



I think the majority of the inteference is from the wall jacks. It was my first time doing such installations, so i probably messed up somewhere. Instead of taking it apart or attempting to install a continous wire (I wanted a clean install, not a rogue cable jutting out of a drilled hole or a wire squished into the crack of a door), I want to design something around that to make it most efficient. I don't know if I'm making any sense or not.

As far as I know the NICs are not the problem in installing the switch. The trouble comes up when the switch attempts to autosense the connection to the router and becomes confused. It attemtps to connect at 100mb but cannot, and will not drop down to 10 mbs, much like a laptop I used using a Xircom 10/100 Realport2. The Xircom modem would indicate a connection at 100mb, but no packets could be sent at all. Only when it was "manually" set to 10 mbs would packets transfer.

The solution would be to have a 10/100 managed switch, opposed to auto sensing. OR even a 10Base Switch. However, the consumer level market has neither... So i'm pretty much screwed, unless I change out the cable/walljacks... or find out a way around things in a most efficient manner.

[Edited by spoon805 on 06-26-2001 at 12:18 AM]

[spoon805]

from what people have replied, I have come up with another question ...

If I use this design:

Router(w/ 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?

[Edited by spoon805 on 06-26-2001 at 12:17 AM]

[ragerdl]

As far as I know, it is unwise to connect hubs to hubs, but it is not a big deal to use switches. The key is to not connect a hub to a hub.

As long as your router is a switch too (which I think they are), you should be fine. :)

[Leon]

Originally posted by spoon805
from what people have replied, I have come up with another question ...

If I use this design:

Router -> 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?


By your description, you just want to use the hub as a repeater, right? Well, if that's the case I don't think it would hurt too much. I seriously doubt your Internet connection is going to exceed 10Mbps, so your setup should be fine. Going from PC to PC file transfers should be at a full 100Mbps because they are on a switch.

But Jeffbx is correct. Router --> Switch --> Hub --> PCs is the ideal way to go usually, UNLESS you plan to do a lot of PC to PC transfers within your subnet. If your subnet sees a lot of Internet action (online games, FTP, streaming) then you will get some collisions.

See if you can't minimize the number of breaks in your setup. That's probably where all your EMI is coming from.

So there's no way to go:
Router --> Switch --> PCs? Forget about making the place look pretty and get a 100 meter cable from the router to the switch. From there you can have 4-6 100 meter ethernet cables from the switch to the PCs.

[spoon805]

Originally posted by Leon
[QUOTE]Originally posted by spoon805


By your description, you just want to use the hub as a repeater, right?

I think I know what you mean, but can explain what you mean by "repeater"... Thanks Leon

[Leon]

Originally posted by spoon805
I think I know what you mean, but can explain what you mean by "repeater"... Thanks Leon [/B]


When you run data through a cable, you will get signal degradation called attenuation. This usually isn't a big deal because you can run 100 meters of cable before the data gets too bad. If you want to run the cable longer than 100 meters you need a repeater. A repeat basically strengthens the digital signal running through the cable. All powered hubs and switches can be used as a repeater.

[ragerdl]

Good definition Leon.

The repeater also "realigns" the signal, as it reads in the semi-jumbled (from interference) and weaker (from attenuatoin) signal and sends it out again without the jumbled stuff.

Oh how cool it would be to be a computer engineer,
Corsair

[Grimm]

Just remember not to get caught. Every person you add to your network increases the chance some idiot will blab. All it takes is one moron who is not happy about his connection speed to rat you out. Then all your hard work nad hardware is for nothing when they terminate your service.

Keep it small, keep it quiet.

[verve247]

Last summer, i did something similar to you, wiring an apartment, so maybe i can help.

Everytime there is a break and reconnection in a cable (cable-> walljack->cable) your connection speed is going to go down. The more breaks you have, the slower it is going to get when reaching your final destination (router to pc). I think it is really essentially to have one continuous backbone. I'm thinking there is just too much degradation from the cables to maintain a 100mb connection

quote:
--------------------------------------------------------------------------------
Originally posted by spoon805
Instead of taking it apart or attempting to install a continous wire (I wanted a clean install, not a rogue cable jutting out of a drilled hole or a wire squished into the crack of a door), I want to design something around that to make it most efficient.
--------------------------------------------------------------------------------

I hate to say this, but in my opinion, if you plan to expand, i think your going to have to redo the setup and put in one continuous wire. And you can do this as a clean install. Just buy a stud finer and a very long drill bit (i have to say this is the most fun part, drilling holes in walls with an 18in drill bit. heh). And then there are panels (similar to light switch panels) that can cover the holes up.

My setup went modem->router->switch->jack in rooms. The only reason you may want a hub is if you want to only send one wire to a room (making the setup cleaner and more streamline.) Then attach the hub in the apartment from the jack.

Hope this is a help. Just rememeber to cut down on breaks and reconnections if you want a fast network.

[spoon805]

Thanks verve247

I talked to one of my friends on the network... and we are gonna seriously thinking about spending a few days in the next months doing what you and many other advised. We will most likley not even use any jacks at all.

Anyone know of a good place to get Cat 6 (hehe, over board... but oh well, gonna get this right)