1: Main knowledge points (this part does not need to be clearly understood at present, it is roughly covered)
Link Layer Overview, Error Detection and Correction Techniques, Multiple Access Links and Protocols, Switched Local Area Networks, Link Virtualization: Networking as a Link Layer, Data Center Networks.
Two: Link Layer Overview
A: Any device running a link layer protocol is called a node. Nodes include hosts, routers, switches and wifi access points.
B: A communication channel connecting adjacent nodes along a communication path is called a link
C: When passing through a specific link, the transmission node encapsulates the datagram in a link layer frame and transmits the frame to the link
1: Services provided by the link layer
A: Framing, link access, reliable delivery, error detection and correction.
2: Where is the link layer implemented
A: The bulk of the link layer is implemented in a network adapter, which is sometimes called a network interface card. At the heart of the network adapter is the link-layer controller, which is typically a dedicated chip that implements many link-layer services.
Three: Error detection and correction technology
A: Detect and correct for proportional impairments in link layer frames sent from one node to another physically connected adjacent node.
1: Parity check
2: Inspection and Methods
3: Cyclic redundancy detection
Four: Multiple Access Links and Protocols
A: A point-to-point link consists of a single sender at one end of the link and a single receiver at the other end of the link.
B: Broadcast Link: It enables multiple senders and receivers to be connected to the same, single, shared broadcast channel.
1: Channel Division Protocol
2: Random Access Protocol
3: Rotation agreement
4: DOCSIS: Link Layer Protocol for Cable Internet Access
Five: Switch LAN
1: Link Layer Addressing and ARP
2: Ethernet
3: Link layer switch
4: Virtual LAN
Six: Link Virtualization: Network as Link Layer
Seven: data center network
1: load balancing
2: Hierarchical Architecture
3: The development trend of data center network