User:Becha/InternetPlumbing/Layers

Description of OSI layers

Borrowed from: https://en.wikipedia.org/wiki/OSI_model

The recommendation X.200 describes seven layers, labeled 1 to 7. Layer 1 is the lowest layer in this model

MODIFIED!!!

TCP/IP Model	OSI Model
	Layer	Protocol data unit (PDU)	Function<ref>Template:Cite web</ref>	Examples
Application	7. Application	Data	High-level APIs, including resource sharing, remote file access, directory services and virtual terminals	TLS, FTP, HTTP, HTTPS, SMTP, SSH, Telnet
	6. Presentation		Translation of data between a networking service and an application; including character encoding, data compression and encryption/decryption	CSS, GIF, HTML, XML, JSON
Transport	5. Session		Managing communication sessions, i.e. continuous exchange of information in the form of multiple back-and-forth transmissions between two nodes	RPC, SCP, NFS, PAP,
	4. Transport	Segment (TCP) / Datagram (UDP)	Reliable transmission of data segments between points on a network, including segmentation, acknowledgement and multiplexing	NBF, TCP, UDP
Network / Internet	3. Network	Packet	Structuring and managing a multi-node network, including addressing, routing and traffic control	AppleTalk, ICMP, IPsec, IPv4, IPv6
Link layer	2. Data link	Frame	Reliable transmission of data frames between two nodes connected by a physical layer	IEEE 802.2, L2TP, LLDP, MAC, PPP, ATM, MPLS
	1. Physical	Bit	Transmission and reception of raw bit streams over a physical medium	DOCSIS, DSL, Ethernet physical layer, ISDN, USB

Layer	Example	Practically	Owner	Developed by	Vulnerabilities/Dangers	Securing	Alternatives
Physical	HW - end user equipment	Computer, tablet, phone...	User	Commercial companies: Apple, Siemens, Samsung...	Un-ethical manufacturing, security backdoors, pollution caused by e-waste disposal,	Hard:	Open HW movement; fair-phone; DIY, Repair Cafes, fair-trade...