> 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.md).

# Data-Link Layer

From amongst the [TCP-IP Layers](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ8l67L5MHnaQIEh9W/tcp-ip-layers), the Second Layer is the Data-Link Layer.

* HTTP asks for the Web pages from a Web Server, TCP provides guaranteed delivery through Error recovery feature, Network Layer's IP provides Addressing & Routing feature for Intra-Network connectivity & Data Link-Layer's Ethernet provides Inter-Network Connectivity with the help of [Ethernet ](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ8l67L5MHnaQIEh9W/an-ethernet)Headers & Trailers (encapsulated by Data-Link Layer).
* Data-Link Layer uses the same [Data-Link Layer Standard ](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ8l67L5MHnaQIEh9W/data-link-layer-standards)over all these different Physical links (within that Ethernet LAN).
* The most commonly used [LAN Data-Link Layer protocol](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ8l67L5MHnaQIEh9W/lan-data-link-layer-protocols) is **Ethernet** & [WAN Data-Link Layer protocols](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ8l67L5MHnaQIEh9W/wan-data-link-layer-protocols) are High-Level Data Link Control (**HDLC**) and Point-to-Point Protocol (**PPP**). 

## Reference:

CCNA 200-301 OCG, Volume 1, Pg. 25 - Wendell Odom .