what is the media access layer for a mac

If the CRC it calculates is different from the CRC checksum in the CRC checksum field, the CRC check has failed.

The MAC address is most frequently represented as 12 hexadecimal digits.

The MAC address uniquely identifies a specific network device and MAC addresses must be unique on a given LAN (a network of computing devices in a single subnet of IP addresses).

The first 12- bit portion of the MAC address identifies the vendor of the network device, the last 12- bit portion identifies the unique id of the device itself.

When looking at a hexadecimal representation of the MAC address, the first six hexadecimal digits identify the vendor and the last six hexadecimal digits identify the specific network interface card.

There is some difference in how they are displayed on different types of computers.

The hexadecimal digits are the same, but they are separated or grouped differently when displayed.

Different companies like to show MAC addresses different ways.

The 24 bits used to identify a host allows for up to 16.7 million unique card addresses on one network.

Since there are more than 16.7 million computers in the world, this clearly isnt enough addresses for every computer on earth, is it.

See ARP and RARP on how IP addresses are tranlated into MAC addresses and vice versa.

If two devices have the same MAC address (which occurs more often than network administrators would like), neither computer can communicate properly.

On an Ethernet LAN, this will cause a high number of collisions.

Duplicate MAC addresses separated by one or more routers is not a problem since the two devices wont see each other and will use the router to communicate.

Not all protocols provide for establishmentteardown, flow control and error recovery.

The content of this field is dependent upon the specified standards for that particular data link layer protocol ( Ethernet, Token Ring, FDDI etc.).

In other words, the source MAC in the frame received becomes the destination MAC in the frame transmitted as a response.

For Ethernet and Token Ring the Data Link layer is described as being broken into two sub-layers, the MAC sublayer (for the MAC address and Media Access Control functions) and the Logical Link Control sublayer LLC.

Ethernet, FDDI, Token Ring etc.).

The LLC information is used to keep track of which piece of data is sent to which IP address and application.

For example, the LLC information helps a web browser keep track of which data being received is part of an image in a web page, and which data is the text in the body of the web page itself.

A CRC check is a mathematical forumula that uses the data as input and produces a numeric result that is almost as unique as the input data.

Using the CRC checksum value it is possible to verify the the integrity of the frame.

Before transmitting the frame, the source computer calculates the checksum and places the checksum value in this field.

The receiving computer looks at the same data in the frame and also calculates the checksum.

What Is The Media Access Layer For A Mac