Daisychaining hubs to switches

[eltigre15]

Is it a bad idea to daisy chain 1 layer of hubs to switches in an enterprise network? I feel that it probably is but cannot come up with an explanation. I would think that the switch would just send any packets to the hub and then the hub would broadcast to any computers connected to it and any slowdown would result on that end of the network and not affect everything. Any thoughts?

 

[jlazzaro]

you're correct. I wouldnt go ahead and put a 12 port hub on every switch port, but here and there it's all good. I do it a lot when I only have a single network drop and need multiple connections.

hub = $15
5 network drops = $800

just make sure you or someone else doesnt plug 2 switch connection into the same hub...loopty loop.

 

[dphantom]

Buy a low end switch like the 5 port Linksys EZXS55W. For less than $25, you get a dedicated switch port and don't have to wory about broadcast traffic. I would never put a hub in my network anymore today.

 

[spidey07]

The year is 2007. There is no such thing as a hub anymore. They have ceased to exist.
😉-

 

[James Bond]

To answer your originally question: it is not advisable to be using hubs all over your network.

However, would plugging in some hubs into your switchports kill your network? No. Thanks to microsegmentation, the switch won't be broadcasting everything that comes at it. As you mentioned, your hubs are going to broadcast everything to the PC's, though.

As long as you don't have too many hubs, or hubs linked with hubs, you should be okay.

But like dphantom said, you can get some cheap switches for under $30 now.

 

[spidey07]

Just to point out....

Swichtes do indeed flood broadcasts and multicasts.

I know some folks have been to class, but hubs operate at layer1, switches operate at layer2. All switches send broadcasts to all ports, just like every bridge ever in existence does.

 

[nweaver]

Originally posted by: spidey07
The year is 2007. There is no such thing as a hub anymore. They have ceased to exist.
😉-

shhh....I still bust out my hubs for sniffing, when I don't want to be bothered to config a port mon

 

[nweaver]

Originally posted by: spidey07
Just to point out....

Swichtes do indeed flood broadcasts and multicasts.

I know some folks have been to class, but hubs operate at layer1, switches operate at layer2. All switches send broadcasts to all ports, just like every bridge ever in existence does.

If you don't understand this post, then google OSI model please!!

 

[cmetz]

spidey07, actually, hubs do exist. They've gone the way of the turntable - if you need one, you NEED one, and you will buy the high-end one. It's only the cheap hubs that are off the market.

And remember that good switches (usually the managed ones, and if you want it to work *right* the higher-end ones) do a decent job of filtering multicast, and can rate shape or storm protect broadcast.

eltigre15, unless your switch is stupid or operating way out of capacity, once it has learned where a station's MAC address is, it will only send things out the port that it thinks that station is down from. So it will not normally send a lot of excess traffic down the other switch ports. Cascading hubs off of a switch in the middle is exactly how things were done when switches first came out - this provided a way to keep your L1 collision domain under control as your network grew, and thusly helped performance a lot (collisions are *bad* for performance). As time went on the price premium for a switched port dropped dramatically, and now, today, you have to deliberately look for and pay more for a hub, because it's a specialty item.

An all-switched network is usually easier for a non-expert IT staff to build and maintain a working network out of. There are many headaches associated with a true CSMA/CD network that you just avoid. There are downsides to switches, but most home and business environments won't be hurt by the downsides, and benefit from the upsides - so for most folks switches are the better choice.

 

[cmetz]

Tizyler, you can chain hubs to hubs. They become one big collision domain. You do have to watch the propogation delay limits though (5-4-3).

nweaver, if you insert a hub into a random place on a random network to do sniffing, you can do *a lot* of damage. Get a real tap. They're cheap compared to potentially hard to diagnose harm.