What is LLC in Ethernet frame?

In the IEEE 802 reference model of computer networking, the logical link control (LLC) data communication protocol layer is the upper sublayer of the data link layer (layer 2) of the seven-layer OSI model.

What is IEEE Standard explain 802.2 standards in detail?

The IEEE 802.2 standards for Logical Link Control define a programming interface between that part of the communications software that controls the network interface card (the Media Access Control and Physical Medium Dependent components) and the overlying protocol stack (IP, NetBIOS, NetWare, etc.).

What are the fields in an LLC PDU?

LLC protocol data units (PDUs) contain addressing information. This addressing information consists of two fields; the Destination Service Access Point (DSAP) address field, and the Source Service Access Point (SSAP) address field. Each of these is an 8-bit field and each is made up of two components.

What is LLC snap?

The Subnetwork Access Protocol (SNAP) is a mechanism for multiplexing, on networks using IEEE 802.2 LLC, more protocols than can be distinguished by the 8-bit 802.2 Service Access Point (SAP) fields.

What is the format of LLC header?

The LLC Header consist of DSAP (Destination Service Access Point), SSAP (Source Service Access Point) and the Control field. The two 8-bit fields DSAP and SSAP allow multiplexing of various upper layer protocols above LLC.

What is LLC in data link layer?

The Logical Link Control (LLC) sublayer provides the logic for the data link; thus it controls the synchronization, flow control, and error-checking functions of the data link layer.

Why is 802.2 necessary?

802.2 is concerned with managing traffic over the physical network. It is responsible for flow and error control. The Data Link Layer wants to send some data over the network, 802.2 Logical Link Control helps make this possible. It also helps by identifying the line protocol, like NetBIOS, or Netware.

What is frame format of Ethernet?

Ethernet (IEEE 802.3) Frame Format – This is a pattern of alternative 0’s and 1’s which indicates starting of the frame and allow sender and receiver to establish bit synchronization. Initially, PRE (Preamble) was introduced to allow for the loss of a few bits due to signal delays.

What is an LLC header?

How does an LLC protocol work?

The LLC sublayer at the receiving end keeps up with the LLC frames it receives (these are also called protocol data units (PDUs)), and if it detects that a frame has been lost during the transmission, it can send back a request to the sending computer to start the transmission over again, beginning with the PDU that …

What is LLC and MAC?

Logical link control (LLC) and media access control (MAC) are the two sublayers that form the data link layer of the OSI (Open Systems Interconnection) model.

WHAT ARE LLC and MAC?

The data link layer (Layer 2) of the OSI model actually consists of two sublayers: the Media Access Control (MAC) sublayer and the Logical Link Control (LLC) sublayer. The MAC sublayer controls device interaction. The LLC sublayer deals with addressing and multiplexing.

Is LLC compulsory for IEEE 802?

Using LLC is compulsory for all IEEE 802 networks with the exception of Ethernet. It is also used in Fiber Distributed Data Interface (FDDI) which is not part of the IEEE 802 family.

Is the IEEE 802 sublayer used in FDDI?

It is also used in Fiber Distributed Data Interface (FDDI) which is not part of the IEEE 802 family. The IEEE 802.2 sublayer adds some control information to the message created by the upper layer and passed to the LLC for transmission to another node on the same data link.

How many frames per second does an LLC2 session have?

Each of the PUs maintains an independent LLC2 session. If each one sends a keepalive every ten seconds, there are 20 frames of overhead every second. If you increase the idle time to 30 seconds, the amount of overhead frames reduces to 6.67 frames per second.

What is IEEE 8802-2 LCC?

IEEE 802.2. IEEE 802.2 is the original name of the ISO/IEC 8802-2 standard which defines logical link control (LLC) as the upper portion of the data link layer of the OSI Model. The original standard developed by the Institute of Electrical and Electronics Engineers (IEEE) in collaboration with the American National Standards Institute…