The network access layer is also called the host-to-network layer. The network access layer is the layer that is concerned with all of the issues that an IP packet requires to actually make a physical link to the network media. It includes the LAN and WAN technology details, and all the details contained in the OSI physical and data-link layers.

Drivers for software applications, modem cards and other devices operate at the network access layer. The network access layer defines the procedures for interfacing with the network hardware and accessing the transmission medium. Modem protocol standards such as Serial Line Internet Protocol (SLIP) and Point-to-Point Protocol (PPP) provide network access through a modem connection. Because of an intricate interplay of hardware, software, and transmission-medium specifications, there are many protocols operating at this layer. This can lead to confusion for users. Most of the recognizable protocols operate at the transport and Internet layers of the TCP/IP model.

Network access layer functions include mapping IP addresses to physical hardware addresses and encapsulation of IP packets into frames. Based upon the hardware type and the network interface, the network access layer will define the connection with the physical network media.

A good example of network access layer configuration would be to set up a Windows system using a third party NIC. Depending on the version of Windows, the NIC would automatically be detected by the operating system and then the proper drivers would be installed. If this were an older version of Windows, the user would have to specify the network card driver. The card manufacturer supplies these drivers on disks or CD-ROMs.

Interactive Media Activity Drag and Drop: The Network Access Layer After completing this activity, the student will be able to identify the protocols used in the network access layer.

   

Web Links Network Access Layer http://www.pku.edu.cn/academic/research/ computer-center/tc/html/ TC0200.html