> For the complete documentation index, see [llms.txt](https://mudassirs46.gitbook.io/network-fundamentals/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mudassirs46.gitbook.io/network-fundamentals/data-link-layer-standards.md).

# Data-Link Layer Standards

* The Entire family of IEEE LAN Standards Standards that together define the Physical Layer & the Data-Link Layers of the Wired LAN technology is referred to as an [Ethernet](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ8l67L5MHnaQIEh9W/an-ethernet).
* Because Physical Layer focuses on sending bits over different types of Physical cables with different types of Length, Medium, etc. Hence there are various types of Physical Layer Standards.
* But [Data-Link Layer](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ8l67L5MHnaQIEh9W/data-link-layer) focuses on sending an Ethernet Frame (Header+Data+Trailer) from the Source Ethernet Node to the Destination Ethernet Node. Hence it uses the same Data-Link Layer Standard over all these different Physical links (within that Ethernet LAN).
* So a LAN may be using Copper+Fiber with different speeds on each link still it will be using one same Data-Link Layer Standard over the entire LAN.

## Reference:

CCNA 200-301 OCG, Volume 1, Pg. 38 - Wendell Odom .


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