# TCP-IP Layers

[TCP/IP Model](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ4cjfS8UXyANv_uLC/tcp-ip-networking-model) (like all the other models) breaks the functions into small TCP-IP Networking Layers with each layer describing a category of functions which includes Standards & Protocols.&#x20;

[**Physical Layer**](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ4cjfS8UXyANv_uLC/physical-layer)**:**

* Focuses on Bits transmission over each Link using Protocols like Ethernet, 802.11 (Wi-Fi).&#x20;

### [Data Link-Layer](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ4cjfS8UXyANv_uLC/data-link-layer):

* Focuses on sending Data over one type of Physical Link (E.g. Ethernet, WLAN, etc.) using Protocols like Ethernet 802.3, 802.11 (Wi-Fi)&#x20;

### [Network Layer](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ4cjfS8UXyANv_uLC/network-layer):

* Focuses on delivering the Data from the original sending Computer to the final destination Computer using Protocols like IP & ICMP

### [Transport Layer](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ4cjfS8UXyANv_uLC/transport-layer):&#x20;

* Focuses on the Applications needed for sending & receiving the Data using Protocols like TCP & UDP.

### [Application Layer](https://app.gitbook.com/@mudassirs46/s/network-fundamentals/~/drafts/-MRZ4cjfS8UXyANv_uLC/application-layer):

* Focuses on the Applications needed for sending & receiving the Data using Protocols like HTTP, POP3, SMTP.

## Reference:

CCNA 200-301 OCG, Volume 1, Pg. 18-19 - Wendell Odom .
