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What is SSAP and DSAP?
SSAP (Source SAP) is an 8-bit long field that represents the logical address of the network layer entity that has created the message. DSAP (Destination SAP) is an 8-bit long field that represents the logical addresses of the network layer entity intended to receive the message.
What is DSAP in computer?
Short for Destination Service Access Point, DSAP is the individual or group address for the address into the upper layers of the network protocol stack.
What is the Ethernet version developed by Dix?
The standard was superseded in 1982, by DIX 2.0, the current Ethernet standard, also known as Ethernet II (or Ethernet Version 2). In 1983, the IEEE (Institute of Electrical and Electronics Engineers, Inc.) introduced the 802.3 Ethernet standard, named after the committee responsible for its development.
What is the frame format of Ethernet?
Ethernet frame format is a continuous pattern of alternative occurring 0’s and 1’s which indicates when the frame is starting and creates synchronization among the sender and receiver. Ethernet frame exist in data link layer of the OSI model (which has 7 layers in it) and is a PDU (aka protocol data unit).
Why LLC and SNAP headers are used?
On other network types, the LLC and SNAP headers are required in order to multiplex different protocols on the link layer, as the MAC layer doesn’t itself have an EtherType field, so there’s no alternative framing that would have a larger available payload.
What is a SNAP header used for?
The SNAP header is used when the LLC protocol carries IP packets and contains the information which would otherwise have been carried in the 2-byte MAC frame type field.
What is the minimum and maximum size of the Ethernet frame field?
To recap, Ethernet has a minimum frame size of 64 bytes, comprising an 18-byte header and a payload of 46 bytes. It also has a maximum frame size of 1518 bytes, in which case the payload is 1500 bytes.
What is the role of SSAP and DSAP in Ethernet?
But, the role of SSAP (Source Service Access Point) and DSAP (Destination Service Access Point) in IEEE802.3 Ethernet frame is confusing and always expressed in high profile. What do these actually help? Each data-link header has a field in its header with a code that defines the type of protocol header that follows.
Is the length of DSAP and SSAP only 8 bits?
But in IEEE 802.2, the length of DSAP and SSAP address is only 8 bits Yes, you are right here. This is related to the history of Ethernet evolution and its subsequent standardization in IEEE. Originally, the Ethernet was invented in Xerox and put forward by Digital, Intel and Xerox (hence the name DIX Ethernet).
What was the role of DSAP in 802.2?
Well, when the IEEE created 802.2, it saw the need for a protocol type field that identified what was inside the field called “data” in an IEEE Ethernet frame. The IEEE called its Type field the destination service access point (DSAP).
What does the address field in DSAP mean?
The DSAP Address field identifies one or more Service Access Points (SAPs) for which the LLC Protocol Data Unit (PDU) is intended. The DSAP address field contains 7 bits of actual address and 1 Address Designation bit to indicate whether that address is an individual (I) destination address or a group (G) destination address.