Network hub vs. switch?

[RobyG]

What's the difference between a network hub and a network switch? Has switches replaced hubs?

[Chris]

The following links should help explain the differences.

http://www.stanford.edu/group/networking/lnaguide/docs/hubs-vs-switches.html

http://www.draytek.co.uk/products/hubvsswitch.html

Hope the above helps.

[Jack Frost]

Nice links very informative... ;D

[CISSPaskme]

Remember the OSI model? In what layer do hubs fall into?
The answer is layer 2. The data link layer.

A bridge also falls into layer 2. Both devices connect different LAN segments, right?

A switch combines the functions of a repeater and the functions of a bridge. So it also falls into layer 2.

A switch amplifies the electrical signal, like a repeater but it has the intelligence of a bridge.

There are some switches that are high functioning they are called multilayered switches. These fall into layers 2 and 3.

Routers fall into layer 3. Layer 3 inserts information into the packet's header so that it can be properly routed.

I hope this helps. :)

[odsamuels]

Not counting mulit-layered switches, wouldn't you say a bridge is more intelligent than a switch though?

Just a quick quest.
L8r

[CISSPaskme]

When a frame comes to a bridge, the bridge looks at it and determines if the MAC address is on the local network or not. It the MAC address is not on the local segment, the bridge will forward it to the next segment. It forwards it to the port that the destination network segment is connected to.

When a frame comes to a switch, it sends the frame directly to the destination COMPUTER. It is faster. A switch is a high speed bridge. This reduces collisions on the network.

A switch is a multiport bridging device. There are 3 layer switches and 4 layer switches. The higher the up you go on the OSI, the more intelligent. :)

[Dutch]

off the bat a Switch is better a hub broadcasts packets across all ports the switch doesnt thus cutting down on network traffic which is important to people like me

[kknight]

Yes.. A hub does broadcast packets across all ports. A switch memorises the MAC addresses and will only accept packets sent to specific addresses. Hence, switches cut down on network traffic whilst hubs are less/not efficient at doing this.

[wheelman]

Switch over a hub anyday.

[Xenocrates]

Excellent explanations of the differences CISSPaskme, but RobyG's question is only partially answered.

Switches have not completely replaced hubs. Yes, switches are faster and more powerful devices than hubs (for reasons already eloquently exhibited by our friend CISSPaskme), but you'd only implement a switch in a corporate environment. Switches are prohibitively expensive when compared to hubs. Hubs are just fine if you only want to connect a few people - like about up to 10 people tops.

However, if you are implementing an enterprise scale lan with many subnets (we're talking about up to hundreds of people now), a switch is a more sensible (and cost-effective) choice.

In summary:
For casual home and small office uses for a few ppl: Use Hubs
For performance dependent business applications: Use Switches

There are a few cases where using both devices can be used in tandem. But that's kinda lengthy to explain here.

Good job CISSPaskme.

- Xeno

[Chris]

Switches are prohibitively expensive when compared to hubs. Hubs are just fine if you only want to connect a few people - like about up to 10 people tops.

Xeno, the prices of switches are not as prohibitive as when they first hit the market. You can also get as low as a 8-port switch. My recommendation would be to get a switch even for home use, you can never tell what that home network can grow into ;)

[Xenocrates]

They make switches for home use as well? Can you imagine hosting an Unreal Tournament match across the net on that baby with friends connecting via internet and locally?

Wicked sick! :o ;D

I'll add that to my memory engrams: "Home based switches" - nice...

[finni03]

Switches give you full 100/1000 MB on every port. Plus switches facilitate management systems via http and telnet. Swithes can also do V-Lans as well as packet filtering based on mac addresses. Hubs on the other hand only accept a signal on one port and rebroadcast it on the rest. thus only one person can transmit an recieve on a hub. I this day and age Hubs and swithes are close to the same price. Thus in the words of Cisco Systems: Why buy hubs when u can buy switches?

[deakie]

i love switches more than hubs because you can basically shove any network cable in it and it works. no more worrying if its a patch xover or standard.
buy di switch :)

netgear does 4 and 5 port switches cheap and they have never given me any probs.

[matronyx]

There is more a chance of packet collision with hubs than with switches. This may not be a big deal for persons who want to run a small lan-party, but in a environment where precision is important, go with a switch.

[kknight]

A hub broadcasts packets all over the network. A switch memorizes the MAC addresses and sends packets to the right nodes. Hence, a switch cuts down on network traffic and saves bandwidth. Replacing hubs with switches will give your network a real performance boost...

[Chris]

Ok, I'm curious about something.

Yes, I know that switches are faster and in many ways better than a hub. But tell me something guys. I have a small 8-port 10/100 hub on my home LAN. I have up to 4 PCs connected to the hub along with my ADSL modem/router. Question - will I really recognize a performance increase if I replace by hub with a switch?

[Xenocrates]

You probably won't notice a performance difference unless you have at least two subnets on your network each running at least 4 PCs each and you're running some HARDCORE network based application like a LAN game.

Note that I said earlier in this same thread (if not here, then elsewhere) if it's for home purposes, a hub is far more cost effective. Buying a switch for your home is like buying a high powered semi-automatic rifle with a top mounted scope with 500x amplification to kill a house fly. It's simply overkill.

Ofcourse people still do it anyways. There are actually idiots who buy 21" monitors to sit at home with, or overclock their pcs to 3.06 Ghz just so that they can read e-mail and surf the net, or buy a 250Gb hard drive to store pictures from their wedding. It's overkill Chris. That's all I'm saying.

Unless you live in a big freaking mansion with several hundred feet of cat5 all over the place with two pcs for every guest room, helper's quarters and for your dog scruffy, stick with the hub. Switches are and will always be for hardcore home network people. For that reason, Switches will never replace hubs. ;)

[deakie]

yes but if you have loads of collisions then the switch reduces that. depends if your hub is being thoroughly used innit.

[Xenocrates]

For a home network of 4 PCs... collisions if any, are negligable.

[jamrock]

Switches are faster so all things being equal, a switch should result in faster throughput.

It may be more important to review the type of data that is being sent and the nature of the existing bottlenecks.

If people are surfing the web, the speed of the internet connection may be the real bottleneck. Speeding up data transfer on the LAN will not make a difference if the hub is currently transferring data more quickly than the ADSL connection.

I have even seen where the real bottleneck was the 10 MPS network cards that had been purchased x years ago.

[Nemesis G4]

It is good to note that a hub and a swith does basically the same job. What you must consider is the use thereof. For instance, if you are sharing a ADSL connection across a couple of computers, there won't be much of a difference whether you use a hub or switch as the computers are all fighting for access to one port i.e the one with the active ADSL connection. But if it is a case where there are more than one resource to be accessed, for instance a printer, a shared folder on another machine and internet connection, then different users will require different resources at any one time. This is where the switch would prove to be more usefull than the hub.

Just a thought in making a better choice.

[matronyx]

Hub
10/100 Ethernet Hubs are only half duplex - each client can only send OR receive data at a particular time.*
Total network bandwidth is limited to the speed of the hub, i.e. a 10Base-T hub provides 10Mb bandwidth max, no matter how many ports it has. Bandwidth is also shared between the connected PCs.

Switch
A switch has multiple broadcast domains and can be 10/100/1000mbs.
They operate at full duplex allowing your computers to send and receive at the same time.
It is intellegent in that it looks at the mac address contained in the header of the packet. It is able to build and retain a mac address table so that it can send the packet to exactly the correct port and not all the ports. This is what makes it faster then a hub.

[Spawn]

Hub
10/100 Ethernet Hubs are only half duplex - each client can only send OR receive data at a particular time.
Total network bandwidth is limited to the speed of the hub, i.e. a 10Base-T hub provides 10Mb bandwidth max, no matter how many ports it has. Bandwidth is also shared between the connected PCs.


Just to add, if a hub and a switch is broadcasting information at 10mbs, the hub will appear to be much slower because unlike switch is intellegent enough to know which network device to talk to, the hub talks to every device in the network until it gets a response but then as a result, there are a lot of collisions and therefore the hub retransmits info until that particular device responds and during this retranmission of data, time is wasted.