Token Bus (IEEE 802.4) is a popular standard for the token passing LANs. In a token bus LAN, the physical media is a bus or a tree and a logical ring is created using coaxial cable. The token is passed from one user to other in a sequence (clockwise or anticlockwise). Each station knows the address of the station to its “left” and “right” as per the sequence in the logical ring. A station can only transmit data when it has the token. The working of token bus is somewhat similar to Token Ring.
The above diagram shows a logical ring formed in a bus based token passing LAN. The logical ring is shown with the arrows.
The various fields of the frame format are:
- Preamble – It is used for bit synchronization. It is 1 byte field.
- Start Delimiter – These bits marks the beginning of frame. It is 1 byte field.
- Frame Control – This field specifies the type of frame – data frame and control frames. It is 1 byte field.
- Destination Address – This field contains the destination address. It is 2 to 6 bytes field.
- Source Address – This field contains the source address. It is 2 to 6 bytes field.
- Data – If 2 byte addresses are used than the field may be upto 8182 bytes and 8174 bytes in case of 6 byte addresses.
- Checksum – This field contains the checksum bits which is used to detect errors in the transmitted data. It is 4 bytes field.
- End Delimiter – This field marks the end of frame. It is 1 byte field.
Attention reader! Don’t stop learning now. Get hold of all the important CS Theory concepts for SDE interviews with the CS Theory Course at a student-friendly price and become industry ready.
- Difference between Token Bus and Token Ring Network
- IEEE 802.6 (DQDB)
- Inter-Switch Link (ISL) and IEEE 802.1Q
- IEEE 802.11 Mac Frame
- Difference between IEEE 802.3, 802.4 and 802.5
- Efficiency Of Token Ring
- Token Ring frame format
- Problems with Token Ring
- Minimum length of Token Ring
- Implement Token Authentication using Django REST Framework
- Difference between Token ring and Ethernet
- Difference between Early and Delayed Token Release
- Difference between Tree Topology and Bus Topology
- Universal Serial Bus (USB) in Computer Network
- Three-State Bus Buffers
- Difference between Ring Topology and Bus Topology in Computer Networks
- Difference between Star topology and Bus topology
- Difference between Mesh Topology and Bus Topology
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to firstname.lastname@example.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.