Talk:Data link layer

From Wikipedia, the free encyclopedia
Jump to: navigation, search
WikiProject Computing / Networking (Rated C-class, Mid-importance)
WikiProject icon This article is within the scope of WikiProject Computing, a collaborative effort to improve the coverage of computers, computing, and information technology on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
C-Class article C  This article has been rated as C-Class on the project's quality scale.
 Mid  This article has been rated as Mid-importance on the project's importance scale.
Taskforce icon
This article is supported by Networking task force (marked as High-importance).


  • IMHO I Don't see what should need cleanup here. propose cleanup tag removal Ppchailley 08:30, 29 June 2006 (UTC) ppchailley

vandalism on para 3[edit]

So in social contact, one needs to know at least one other person, but not necessarily know Fred Bob, Canada.

who is bod from canada...anyway shame on u boob. -- 05:31, 5 August 2006 (UTC)

OSI Data Link Layer mixed with TCP/IP one.[edit]

It doesnt exist an exact part where the differences are stated. As far as i know OSI is not the same as TCP/IP. -- 02:54, 23 October 2006 (UTC)

Radio Link Control sublayer[edit]

is used in some wireless systems. It should be mentioned here somehow. Mange01 (talk) 22:12, 18 March 2009 (UTC)

Perhaps you should write a section in a UMTS article first and give the term better context. Kbrose (talk) 00:07, 19 March 2009 (UTC)
Good idea. I have not found any good source however. Mange01 (talk) 16:27, 19 March 2009 (UTC)
Perhaps, when you do, you will discover that this is not a Data Link Layer issue, belongs to physical layer, well, or somewhere in between. Kbrose (talk) 18:11, 19 March 2009 (UTC)
Hmm. Perhaps you have Radio resource management in mind, which often concerns the physical layer. Mobility management (handover and roaming) taken care by the MAC sublayer if it is packet switched - and I don't know where it is situated if it is circuit switched. But RLC is something else. It was introduced in GPRS, and to my understanding it is about transferring packet data (i.e. data link layer) over a system that partly is based on circuit switched channel access. In the sources I have seen, it is placed above the MAC layer and below the LLC layer (the latter is not always mentioned). See
[,M1 George Aggelou, Mobile Ad Hoc Networks: From Wireless LANs to 4G Networks, McGraw-Hill Professional, 2005
ISBN 0071413057, 9780071413053, figure 1.22, page 45],
Keiji Tachikawa, W-CDMA Mobile Communications System: Mobile Communications System, John Wiley and Sons 2002, ISBN 0470847611, 9780470847619, Figure 3.3, page 98.. LLC frames are segmented into RLC data blocks, which are embedded in MAC frames. To my understanding, the LLC layer is responsible for the communication between the GGSN node (the "GPRS router" or "packet switch") and the mobile station. This communicaiton is mediated by the base station (BSS) and the base station controlling switching point (BTS). The RLC layer is responsible only for the communication over the radio link between the base station and the mobile station.Mange01 (talk) 22:55, 19 March 2009 (UTC)

Ghastly Second Paragraph[edit]

Parts of this article are atrociously written, such as this non-stellar opening to the second paragraph: "The data link is all about getting information from one place to a selection of other close, local places." The quality does not improve soon enough.

This is a poorly-worded jumble built on specious conceptions. I will try to clarify and correct some of this. --Talinus (talk) 00:30, 8 April 2009 (UTC)

Use of the Term LAN[edit]

"The Data Link Layer is concerned with local delivery of frames between devices on the same LAN." This statement might suggest to a casual reader that the Data Link Layer" is specific to Local Area Networks. That would be incorrect. All networks (LAN, MAN, & WAN) make use of frames to deliver the network layer PDU between devices. —Preceding unsigned comment added by (talk) 14:22, 2 June 2009 (UTC)

Error detection and error correction[edit]

"The uppermost sublayer is Logical Link Control (LLC). This sublayer multiplexes protocols running atop the Data Link Layer, and optionally provides flow control, acknowledgment, and error recovery." The use of the term "error recovery" in this statement might cause confusion between the concepts of error detection and error correction. Layer 2 provides error detection or error notification, not error correction. —Preceding unsigned comment added by (talk) 14:30, 2 June 2009 (UTC)

"Software" and "Hardware" Layers[edit]

"The Data Link Layer is often implemented in software as a "network card driver"." This statement is incorrect and confusing. The driver can only implement the functionality of the hardware. It can never implement layer two functionality independently of the hardware. The upper three layers (5, 6 and 7) of the OSI model are referred to as "Software Layers" because they are fully implemented in software. The bottom four layers of the OSI model are referred to as "Hardware Layers" because they are heavily dependent on hardware devices. —Preceding unsigned comment added by (talk) 14:46, 2 June 2009 (UTC)

Plagiarised from ...?[edit]

What's all the "Figure 4-39" stuff in the huge chunk of unattributed text in the "Data Link Layer Switching" section? Where's that been lifted from? —Preceding unsigned comment added by Gordonjcp (talkcontribs) 10:59, 5 January 2010 (UTC)

Misleading pedagogy[edit]

Section Media Access Control sublayer, second paragraph:

If two people speak at the same time, they will back off and begin a long and elaborate game of saying "no, you first".

No, that's not Media Access Control. The explanation is outright stupid. The real explanation should be:

If two people speak at the same time, they will pick up a 1000 sided die from their respective pocket, and throw it, observing the number that comes up. Then both of them will take up their stop watch and wait for that number of /seconds (or other time unit)/ and after that try to speak up again.

Rursus dixit. (mbork3!) 09:02, 27 July 2011 (UTC)

Your 1000-sided die and stopwatch sounds elaborate to me. Also, rolling the die and running the stopwatch has the intended effect of letting someone else go first most of the time... — Dgtsyb (talk) 09:20, 28 July 2011 (UTC)

Move discussion in progress[edit]

There is a move discussion in progress which affects this page. Please participate at Talk:Physical Layer - Requested move and not in this talk page section. Thank you. —RM bot 03:45, 19 October 2011 (UTC)

'The uppermost sublayer, LLC, multiplexes protocols running atop the data link layer, and optionally provides flow control, acknowledgment, and error notification.'[edit]

'error notification' and later 'error control'.. correct term would be 'error detection'. And actually this is false because CRC is added by MAC sub-layer. The Frame Check Sequence (FCS) field in the Trailer is used to determine if errors occurred in the transmission and reception of the frame, and thats where CRC is placed. Error detection is part of Data Encapsulation, next to frame delimiting and addressing. And data encapsulation is one of primary responsibilities of MAC. - that should be fixed

"Stretched" Layer 2[edit]

I came accross this term today. Refers to methods to "virtually" extend a datalink layer accross WAN links I assume. Can't seem to find any related information on Wikipedia currently? Might be a good addition if it is not yet available.