Talk:Ethernet hub

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Inaccurate statement[edit]

I don't believe the statement "Hubs remain a very popular device for small networks because of their low cost" is accurate. Especially when this article also states that "The availability of low-priced network switches has largely rendered hubs obsolete but they are still seen in older installations and more specialized applications." Hubs are fairly obsolete and mostly used for specialized situations such as packet captures. I am considering deleting this sentence. Switches are cheap. —Preceding unsigned comment added by Daprofessor (talkcontribs) 01:09, 13 February 2009 (UTC)

Article title[edit]

I renamed this from "Hub (computer)" to "Ethernet hub" since there are many different types of computer hubs completely unrelated to Ethernet hubs (e.g., USB hub, application hub, Token Ring hub). --Rick Sidwell 23:13, 19 Jun 2005 (UTC)

I move this article from "Ethernet hub" to "Network hub" because the hub can be used not only in Ethernet physical layer, and the hub can be used in Wi-Fi physical layer. QQ 23:57, 1 December 2007 (UTC)
Excuse me? How does an Ethernet hub operate in a Wi-Fi network? This page should be moved back to "Ethernet hub". Herbert Xu 01:14, 25 June 2008 (UTC)
If there was something special about Ethernet hubs that set them apart from network hubs in general, then, yes, perhaps it would be warranted to have a specific Ethernet hubs section within a Network hub article, or even an Ethernet hub article. However, I do not see any content in this article that does not apply to non-Ethernet network hubs for other Layer 1 protocols, such ATM hubs.
Therefore, I recommend renaming this article Network hub, unless someone can show why something in this article makes it Ethernet-specific, in which case, the article should be renamed anyway, and what little Ethernet-specific content there is moved to an Ethernet hub section within it. SixSix (talk) 21:24, 14 October 2008 (UTC)
Sorry, your conclusion doesn't follow from the above conversation. Reread the comment at the top of this section. Despite the fact that "Network" is sprinkled in front of "hub" a few places, this article currently covers the Ethernet repeater hub. If you feel strongly about this I suggest you create a new Network hub article and tie it in with the existing Hub articles. --Kvng (talk) 05:21, 17 October 2008 (UTC)

Switching hub[edit]

I encountered the term "switching hub" but I was never sure what it means. It should probably be explained here, or does it require a separate article? aditsu 22:02, 22 February 2006 (UTC)

Speaking as a cynic - it was probably a salesman thinking that his product would sell better if it had "switch" in its name :-)
Speaking more serioiusly... it's likely to be a device that operates like a hub in that it sends all incoming packets out through all links, but is implemented like a switch in that it uses store-and-forward handling. Such a device can have advantages - for one, it's capable of connecting both 10-Mbit and 100-Mbit ports at the same time, something that a "passive" hub can't do.
But these terms are often used very loosely - if it's on the web, paste a link to it. --Alvestrand 07:12, 23 February 2006 (UTC)
Well, several pages, such as [1], [2] and [3], seem to describe "switching hub" being the same thing as "switch".
I had the impression that there was a difference. More exactly, I (vaguely) thought "switching hub" meant one of these two things:
  • a 10/100 hub, as opposed to a 100-only (or 10-only) hub, or
  • a hub that has one special "link" port with a separate collision domain (but I'm not sure if such a thing really exists)
If it is actually the same thing as a switch, then this should be mentioned at network switch, and perhaps create a switching hub redirect to it. aditsu 08:11, 23 February 2006 (UTC)
The references seem to indicate that it's indeed a switch, and the only difference between "network switch", "switch" and "switching hub" is that you can tell that the "switching hub" is an Ethernet switch, and not one of the million other things that are called "switch".... I stand corrected, thanks! --Alvestrand 08:30, 23 February 2006 (UTC)

I have a question: Can you connect a dualspeed(10/100) ethernet hub to a singlespeed(10) hub?

I assume you're doing this in a museum somewhere because it is hard to find this equipment anymore. But yes, the dualspeed hub should detect that it is connected to a 10 Mbit port and operate appropriately. --Kvng (talk) 05:21, 17 October 2008 (UTC)

Layer 1 switch, concentrator, repeater hub[edit]

I've never heard the term "Layer 1 switch" before in networking. It does show up (sparsly) in an internet search as a synonym for "Physical layer switch" but both appear to refer to a crossbar switch or relay bank, not specifically networking equipment. I've removed the reference.

"Concentrator" is usually used to describe a patch panel. Part of the cable plant, not the network gear described by this article. I've removed this as an alternate name for hub.

In my experience, hub is a sloppy term for this device. The term sometimes refers to network switches as in "switching hub" as discussed above. "Repeater hub" is more precise and preferred term for the device described by this article. —Preceding unsigned comment added by Kvng (talkcontribs) 21:21, 11 August 2008 (UTC)

Yes, the term should be "repeater" or "repeater hub." Hub describes the topology, not the electrical function. As the first hubs were repeaters, the term tended to get used as it was shorter, but it is incorrect now that there are "switching hubs" (technically "bridging hubs" with more than two ports). Gah4 (talk) 19:58, 11 September 2010 (UTC)

Would you support renaming the article Ethernet repeater hub? --Kvng (talk) 21:08, 11 September 2010 (UTC)
I do not see a need for a rename. The common term is (or was) "hub" and that is the appropriate name. A "switching hub" is just a switch; people sometimes used the longer expressions to avoid confusion with newcomers, or for precision because many simple switches are identical in appearance to a hub. Johnuniq (talk) 01:56, 12 September 2010 (UTC)
If an "Ethernet hub" can mean either a repeater or a switching hub (as Gah4 (talk · contribs) corroborates), this article is misnamed becacuse, as written, it describes only the repeater hub. --Kvng (talk) 17:05, 12 September 2010 (UTC)

In the beginning of 10baseT there were only repeaters, and "hub" was a conveniently short form for the name. As it describes the topology, but not the function, it is also misleading. Repeating hub, or just repeater, is much better (but longer). I would vote for a separate hub page (or disambiguation page) with links to repeater (or repeater hub), and switch (or switching hub). (Even though technically a switch or switching hub is an ethernet bridge.) Gah4 (talk) 01:28, 20 September 2010 (UTC)

Words like "hub" in an industry like networking are rarely precisely defined, and are subject to change as trends move technology in new directions. In my world, a "hub" has never been a "switch", although there are plenty of confused people who use all combinations of the terms. Per WP:COMMONNAME, the title of an article should be its commonly known name. Note that "commonly known" may not agree with what is written in some "encyclopedia of networking". My experiences may not be typical, so my understanding of what the common name is may be out of date, but I think some sources other than our opinions would be useful before renaming the article. Johnuniq (talk) 01:16, 13 September 2010 (UTC)
Sounds reasonable. We'll let this one lie for now. --Kvng (talk) 01:34, 13 September 2010 (UTC)

Description of the Parameters Added in the WikiProject Computing Template.[edit]

Computer Networking WikiProject Support and Importance: This article was already supported by the Computer Networking WikiProject, marked with unknown importance, so I kept this article under the project's support, as it seems befitting, but marked it with top importance because ethernet hubs enable basic connections, the fundamental components of networks.

Class: I rated this article as a stub-class article because it has absolutely no sources. According to the WikiProject Computing assessment page (http://en.wikipedia.org/wiki/Wikipedia:WikiProject_Computing/Assessment#Grades), if an article has no listed sources, it is a stub, regardless how informative, well-written, or long it is. This is simply because such articles are not verifiable, which Wikipedia holds in very high regard.

Importance and Portal: The article falls under the description of low importance from the WikiProject Computing assessment page (http://en.wikipedia.org/wiki/Wikipedia:WikiProject_Computing/Assessment#Grades). The Computing WikiProject is concerned with fundamental components for computation, not networking connections. However, the article is not completely unrelated to the very general Computing WikiProject and falls under many subcategories of the Computing WikiProject (which is why I added this Computing WikiProject template and the computing portal).

Infobox: This article is technically lacking an infobox, so I noted that.

Computer Hardware task force WikiProject Support and Importance: An ethernet hub is obviously a piece of hardware, so I marked this article as falling under the Computer Hardware task force WikiProject. Since this piece of hardware is the sole object that allows for computer networks, I marked this article with High-importance under the Computer Hardware task force Wikiproject.

Computer science WikiProject Support and Importance: This article obviously falls under the general category of computer science since it is related to computers and allows computer networking. However, since ethernet hubs do not form the basis of any general concepts in computer science, this article seems to be of low importance with respect to this science.

WikiProject Websites Support and Importance: Since network sites can be accessed from ethernet hubs, it seems that this article relates to the Websites WikiProject. However, the relation is very indirect, since ethernet hubs, being hardware, are qualitatively different from websites and any of the components required for the creation of websites. Hence, I rated this article as being of low importance in this area. --Some Old Man (talk) 01:24, 21 May 2009 (UTC)

Is a hub a node?[edit]

See the node (networking) article. Mange01 (talk) 23:15, 5 June 2009 (UTC)

No. A hub is part of the network infrastructure and thus it's not a node.-- Zac67 (talk) 22:29, 26 September 2009 (UTC)
Yes. A hub is a place where more than two network devices are interconnected. Definitely a node. --Kvng (talk) 04:12, 27 September 2009 (UTC)
After rereading the node article it seems I've got to adjust my definition of "node". Template:Zac67

Packets in layer 1 context[edit]

The article repeatedly talks about hubs forwarding network packets. However, packets are entities of layer 3 and don't exist from the very limited POV of a simple hub. A hub/repeater operates on the physical layer which consists solely of bits. One advantage of this is the reduced latency of hubs in contrast to switches. I'll try to incorporate that into the article. -- Zac67 (talk) 22:28, 26 September 2009 (UTC)

The terms "packet" and "frame" are generally used interchangeably in networking. Packets and frames exist at layers 1, 2, 3 and higher. A layer 3 packet passing through a router is not the same thing as the layer 1 packet passing through a hub but they're both packets. --Kvng (talk) 04:12, 27 September 2009 (UTC)
Even though the terms "packet" and "frame" are commonly mixed up, the correct terms are "frame" for layer 2 and "packet" for layer 3, see Data Link Layer for details. However, in the Physical Layer there are neither frames nor packets, just raw bits: "The Physical Layer defines the means of transmitting raw bits rather than logical data packets over a physical link connecting network nodes."
Depends on the layer 1 technology I think. On all Ethernet variants, there is a layer 1 mechanism that identifies the beginning of a frame. On 10 Mbit is is presence of carrier. On higher-speed Ethernet the carrier is always present and a non-data symbols are used to indicate idle and start of frame. Do you have a citation for packets vs. frames? I have always assumed it is along the same lines as octets vs. bytes - different words for different folks. --Kvng (talk) 02:14, 28 September 2009 (UTC)
It is not true that the terms "packet" and "frame" are "generally used interchangeably". A frame is a frame, a packet is a packet. A frame resides in the data link layer, a packet resides in the network layer. If you call a packet a frame or vice-versa any competent network engineer will correct you. Additionally with respect to this article, FRAMING IS ALL LAYER 2. Nitpicking about Layer 1 and framing is just going to confuse people trying to learn something. — Preceding unsigned comment added by 68.38.197.76 (talk) 03:57, 5 May 2013 (UTC)
AFAIK the physical layer is responsible for recovering the bit clock and synchronisation to code symbol (byte) boundaries. The Start Frame Delimiter provides synchronisation to a frame boundary, thus should be part of layer 2. Actually it does provide synchronisation to the symbol boundary as well, so it also belongs to layer 1 - thanks for pointing me to this.
As to frames vs packets - probably I'm a bit overly exact here. "Packet" is a rather general term, but imho when it comes to Ethernet, it often simplifies things if everyone knows which layer you're referring to (but even I wouldn't use "frame switching" or "frame radio"). ;-) -- Zac67 (talk) 20:52, 28 September 2009 (UTC)
As I undersand it Ethernet it is the PHY's job to detect the start and end of frames (which is a media dependent task) and inform the next layer up (either a MAC or a repeater) of this fact. MACs need that information to assemble frames. Repeaters need it to decide which direction to repeat data in, to detect collisions and to inform the outgoing PHY so it can generate a valid start and end for the outgoing frame.
You could build a protocol in which the physical layer only handled bits but ethernet is not such a protocol, it is a protocol based on using a preamble and start of frame indicator to indicate to all layers that a packet has started (and IIRC the design allows repeaters to lose some preamble when they forward the packet). Plugwash (talk) 13:27, 6 January 2012 (UTC)

Rename this page?[edit]

Anyone up for giving this the proper name of "Ethernet Repeater" with a redirect from the common name of "Ethernet Hub".

Technically, hub describes the topology, not the function. The fact that repeaters were the first hubs does not make it correct. Gah4 (talk) 21:45, 29 April 2011 (UTC)

I oppose renaming. Per WP:COMMONNAME, calling it "hub" like everyone else does (or did) is correct. If necessary (I don't see why it would be), the article could explain that the name is wrong (with sources). Johnuniq (talk) 01:09, 30 April 2011 (UTC)
I oppose renaming. Repeaters are used to extend the physical reach of segments (esp. 10Base2/5), hubs are used to build star topology networks (10BaseT/100BaseTX). While they are technically the same (hubs are multiport repeaters), the scope of this article concentrates on the hub function. Zac67 (talk) 10:42, 30 April 2011 (UTC)
That is exactly the difference. A hub, as either a repeater or switch/bridge, is used to build a star network, yet this article only describes the repeater. While many networking books might make this mistake, one might hope that it is done correctly here. It seems to me a combination of the fact that the first hubs were repeaters, and that hub is shorter to write, led to this situation. Gah4 (talk) 00:14, 27 September 2011 (UTC)
I agree that "repeater" is considered proper now but back when these things were in common use, everyone called them hubs and so that's probably still the WP:COMMONNAME. --Kvng (talk) 13:30, 2 May 2011 (UTC)

Hmm. Originally they were hubs as the ethernet repeater was the only technology available. Considering WP:COMMONNAME, though, it seems that Reliable Source is an important part of the distinction. What is a Reliable Source in the case of Ethernet? Is it the standards documents, books written by writers of the standard, books by professional network engineers, or any old networking book? Gah4 (talk) 09:03, 26 September 2011 (UTC)

"Any old networking book" doesn't necessarily qualify - many authors were/are wildly imprecise when it comes to naming things (from what I read). BTW, should we integrate network switch into network bridge as well since a switch is nothing else than a multiport bridge device? -- Zac67 (talk) 20:33, 26 September 2011 (UTC)
My favorite are the books by Rich Seifert, who wrote much of the original ethernet standard, and still works on newer standards. Two are "Gigabit Ethernet" which, despite the name, covers slower ethernet standards, and "The Switch Book." Yes, switch and bridge should be appropriately linked. Note that Rich mentions more than once as regard to multiport bridge, the converse being the single port bridge isn't very useful. (It seems that there is no English word meaning "more than two." Gah4 (talk) 00:14, 27 September 2011 (UTC)
When switches were introduced they were not called hubs. They still are not called hubs. There are other non-Ethernet network devices called hubs but there is no ambiguity in calling what is techincally known as a multiport repeater an Ethernet hub. --Kvng (talk) 00:54, 29 September 2011 (UTC)
"it's not a car it's a volkswagen" Note that marketing people don't like to call a product by its ordinary name, they want their product to stand out as special and different. Note that even the "switch" name was invented by marketing instead of the normal ethernet term, bridge. (and note that there are no single port repeaters, bridges, or switches.) Gah4 (talk) 06:00, 30 September 2011 (UTC)
Perhaps true, but I don't understand how this argues for a title change. --Kvng (talk) 18:23, 30 September 2011 (UTC)
Oppose at least capital letters implying it was a proper noun seems totally misleading. There were all kinds of them. Much better would be to point out the ambiguity of the term in the body, with links to other related topics. For example, I see multiport repeater is an article about the general concept, which is fine, except it has zero citations and does not even mention the word "Ethernet" or any of the other kinds of repeaters there are (wireless ones of all sorts). Similarly, network hub redirects here, which covers up all the other kinds of hubs in networks (logical ones as well as physical ones). Especially as wireless networks are becoming so common at the ends compared to wired ones (and bridged hybrid nets), this seems just a stopgap. Perhaps eventually network hub would become a disambig page to articles on the various kinds, perhaps even relevant to broadcast communication network for example, or star network. W Nowicki (talk) 17:16, 17 October 2011 (UTC)

There are (I still have one, though I haven't used it lately) LocalTalk repeater hubs. LocalTalk is the hardware layer for what was originally called AppleTalk, the network hardware built into many Apple Macintosh computers. I used to have a GatorStar which is a 24 port LocalTalk repeater attached to a LocalTalk to EtherTalk Router.Gah4 (talk) 11:39, 6 January 2012 (UTC)

Will a hub also forward the signal to "inactive" ports?[edit]

E. g. will it forward to ports where no network device is connected or where a network device is connected but not active ("Link" LED not lit)? 91.61.243.161 (talk) 13:54, 10 August 2012 (UTC)

If a tree falls in a forest...
Seriously, a 100BASE-T connection doesn't have any data signal until link is established. A 10BASE-T port is less intelligent so might attempt to forward data even if nothing connected. --Kvng (talk) 13:36, 12 August 2012 (UTC)

did a third grader write this?[edit]

The grammar is atrocious..

"There are plenty of features of an Ethernet hub which the people need to be aware of. It is basically used in the LAN systems"

Either that or written by someone of which English is not their native language.

This is English Wikipedia..right? — Preceding unsigned comment added by 68.38.197.76 (talk) 03:49, 5 May 2013 (UTC)

Hub "types" and "explanations"[edit]

Sorry, I have to revert this. There are so many issues it's very hard to salvage

  • passive Ethernet hubs do not exist
  • stackable hubs are not necessarily manageable, they've only got a special stacking port (to circumvent 5-4-3 problems)
  • a switching hub is a network switch, no repeater hub
  • the 'intelligent hub' text is nonsense, please read up on CSMA/CD and Ethernet in general
  • text formatting was totally off

Zac67 (talk) 21:07, 15 July 2013 (UTC)

6-5-4-3-2-1[edit]

According to this article, the 5-4-3 rule applies to 10baseT. It does't. The 5-4-3 rule applies to coaxial (10base5 and 10base2) ethernet, along with FOIRLs. For 10baseT, you can have up to six segments of (about) maximum 150m length, as long as your transceiver cables (if you have them) aren't too long. (Normally you don't have transceiver cables, but the rules don't know that.) Gah4 (talk) 02:32, 18 May 2015 (UTC)

The 5-4-3 rule applies to all repeated 10 Mbit/s varieties, regardless of medium. Don't forget that it's a rule of thumb and not the exact science it's commonly sold for. --Zac67 (talk) 17:30, 21 May 2015 (UTC)
No, the rule is based, in part, on the collision detection method for coaxial ethernet. But there is an important reason for wanting 5 repeaters: it allows a central repeater, attatched to some repeaters, each attached to more repeaters. You can't do that with only four. [1] For 10baseT, you can have five repeaters, six segments, with a total of about 1900m of cable. Six segments of 150m (cat 5 cable for 10baseT) is only 900m. Gah4 (talk) 05:29, 22 May 2015 (UTC)