Talk:Network switch

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edit·history·watch·refresh Stock post message.svg To-do list for Network switch:

Here are some tasks awaiting attention:
    • Remove repetition
    • Merge content to Multilayer switch
    • Improve organization
    • Add historical information

    Industry Analysis[edit]

    This section simply makes no sense. It is very ungrammatical, but impossible to correct as its meaning and intention are obscure. Maybe somebody who knows what it's trying to say can help.

    Section no longer exists. -—Kvng 04:23, 6 January 2013 (UTC)

    Incorrect revenue figure[edit]

    "There are currently 6 major players competing for market share of the $3.659 Billion Dollar networking and telecommunications industry. According to a Dell'Oro report for 1Q06 the market leaders in descending order are Cisco, Nortel, Hewlett-Packard, Foundry Networks, 3Com, and Extreme Networks."

    This figure is obvious nonsense - Cisco alone has an annual revenue of $24 billion. Maybe the wrong thousands separator was used? Furthermore, using a currency symbol in combination with a currency name is redundant (both are commonly understood to refer to the United States Dollar). Other issues: capitalization and the fact that it doesn't state whether the figure pertains to the national (US) or international market. Maybe someone who has correct numbers could fix this, else it should be removed. Aragorn2 13:50, 24 August 2006 (UTC)
    Statement no longer exists in article. -—Kvng 04:25, 6 January 2013 (UTC)

    Marketing vs. technical terminology[edit]

    Ethernet data forwarding entities as per the standards organizations that define these things:

    • Repeater (802.3)
    • Bridge (802.1)
    • Router (IETF)

    "Switch" does not appear in this list.

    Types of "Switches" you can buy:

    • "Switch" that is not 802.1D compliant. This is sometime given the technical designation "Buffered Repeater".
    • A "Switch" compliant with 802.1D is typically seen as a multi-port Bridge.
    • Many "Switches" feature varying levels of Router functionality in addition to their Bridging capability.

    "Switch" can mean many things. It is not a precise term (I call it a marketing term). That's what I am trying to convey in my contributions to this article. --Kvng (talk) 16:55, 22 January 2009 (UTC)

    collisions[edit]

    Switch with 4 ports, for example: As the article notes, A & B can communicate (in full duplex even) without disrupting simultaneous communication between C & D, unlike a hub which merely repeats the raw signal from any node to all (other) nodes (so a hub can only have one node communicating in half duplex before collisions begin being observed by at least some nodes, although perhaps full duplex is possible if all but two nodes silently ignore everything?). But what about if instead, B & C both want to individually communicate with A (leaving D idle) using a switch? In such a case, will a switch repeat both signals (to A from B and from C) such that they collide, or will it cache and reorder the packets (to prevent any possibility of collisions)? And is this possibly what distinguishes a mere switch from a router? Cesiumfrog (talk) 05:52, 19 September 2010 (UTC)

    Connections to a hub always operate half-duplex. On a switch, data sent from multiple ports to a single port will be buffered by the switch. If the pattern persists, the switch can run out of buffer space and packets will be discarded. --Kvng (talk) 06:15, 19 September 2010 (UTC)

    De-facto meaning[edit]

    While WP drowns in technical details, the current article doesn't describe what's the difference between a switch, a hub and a bridge. The devices are different de facto, my CompTIA Network+ book (ISBN 978-0-7897-3796-0) claims that switches are smart hubs that redirect a traffic session only to the intended host. A bridge is, according to the book, more limited: it decides whether to block or let through data traffic from one network to another.

    I think the intro and Function section are confused about the function. Functionally a switch is used as a junction connecting computers in a network, while a bridge is used to connect (usually only) two networks. Rursus dixit. (mbork3!) 16:12, 7 August 2011 (UTC)

    Clarifying myself: those things are mentioned, but not initially where they should be, and mostly drowning in techspeach ("operating at OSI 2 layer") obscuring the essence of the usage. The text needs shuffling, so that the article starts with the function and the usage, then the jargon can escalate step-by-step to make us nerds drool. Rursus dixit. (mbork3!) 16:21, 7 August 2011 (UTC)
    I agree that there is too much jargon in the lead. I do not, however, see any technical issues. The idea of a bridge as a two-port device dates back to when Ethernet networks were built with coax or hubs. Now that these are gone, we have to update our terminology. The 802.1Q standard defines layer 2 switch behavior and "bridge" is the terminology used throughout. --Kvng (talk) 16:19, 11 August 2011 (UTC)
    I agree that terminology has to be updated, but jargon sometimes evolves into common technical meaning different to the technical standards. Can a non-blocking packet switch be fairly described as a bridge, or even a switching hub? "Switching hub" is as obsolete as the original thin-net bridges -- and both terms belong in a history section instead of the intro. "Bridge" is still used to describe point-to-point wireless devices, which could be a useful comparison since they don't switch packets they just send them through to the other end of the link. A laymans description of the Layer 2 concept should still be in the intro because thats the core of its definition. Maybe intro could say: "Switches send data between devices physically connected to them, with basic ones being unaware of the data's final destination or internet address". Webwat (talk) 03:34, 13 October 2013 (UTC)
    I think we'd all need to take a look on how these devices do their job – simply looking at what they do quickly blurs the distinction between repeaters, bridges and routers. What is commonly called "switch" is per definition (IEEE 802.3) a multiport bridge. What does a bridge do? A bridge takes a decision based on the destination's MAC address. A simple two-port device just decides whether it forwards a given frame or not. A multiport bridge makes this decision for each port it's got, essentially deciding where to forward it to.
    In this line of thought, a repeater (hub) does not take any decision, and a router's decision is based on layer 3 information (commonly the IP address). Zac67 (talk) 10:16, 13 October 2013 (UTC)