Data Link Layer 2 Basic Services
Data Link Layer 2 Basic Services
At each hop the received frame is examined for errors, if an error is found in a frame, then the frame is ____
Discarded
The technique used for getting the frame on and off media is called_____
the media access method or MAC Method
Control information can describe the following
The data link layer frame includes the following elements:
Data, Header, Trailer
The packet from the network layer
____ link layer addressing is contained within the frame header and specifies the frame destination node on the local network.
Data
The control information, such as addressing, located at the beginning of the PDU
The frame ____ contains the control information specified by the data link layer protocol for the specific logical topology and media used.
Header
The control information added to the end of the PDU
Data link layer protocols add a ____ to the end of each frame.
Trailer
Typical field types include:
The beginning and end limits of the frame
Start and stop indicator fields
The destination and/or source devices
Addressing or naming fields
The type of PDU contained in the frame
Type field
The control fields
Quality
The frame payload (network layer packet)
Data field
the data link layer is embodied as a physical entity, such as an Ethernet ______, which inserts into the system bus of a computer and makes the connection between running software processes on the computer and the physical media.
network interface card (NIC)
The two common LAN sublayers are as follows:
Logical Link Control (LLC)
MAC
places information in the frame that identifies which network layer protocol is being used for the frame.
Logical Link Control (LLC)
provides data link layer addressing and delimiting of data according to the physical signalling requirements of the medium and the type of data link layer protocol in use.
MAC
Engineering organisations that define open standards and protocols that apply to the data link layer include:
Controlled Access for Shared Media
Contention-Based Access for Shared Media
in Contention-Based Access, Uses a _____ process
to first detect whether the media is carrying a signal
carrier sense multiple access (CSMA)
CSMA is usually implemented in conjunction with a method for resolving the media contention.
The two commonly used methods are:
CSMA/Collision Detect (CSMA/CD)
CSMA/Collision Avoid (CSMA/CA)