Chapter 3: Protocols and Models
Message Timing
Includes the following : -Flow control -Response Timeout -Access method
Internet- 2nd layer TSI/IP Model
Determines the best path through the network.
Access method
Determines when someone can send a message. -There may be various rules governing issues like "collisons". This is when more than one device sends traffic at the same time and the messages become corrupt. -Some protocols are proactive and attempt to prevent collisons, other protocols are reactive and establish a recovery method after the collison occurs.
Internet Engineering Task Force (IETF) Internet Standard Organization
Develops, updates and maintains internet and TCP/IP technologies. This includes the process and documents for developing new protocols and updating existing protocols.
Standards-based protocol suite
It has been endorsed by the networking industry and approved by a standards organization. This ensures that products from different manufacturers can interoperate successfully.
Open standard protocol suite
It is freely available to the public and can be used by any vendor on their hardware or in their software.
Data Link example by me as Follows: PC1->home router-> Server Router-> Server
MAC addressing segment hops: 1st: Source (PC1 NIC) sends frame Destination- (1st router- Default gatewayDGW interface) receives frame 2nd: Source- (1st Router- exit interface) sends frame Destination- (Secound Router) recieves frames Last: Source- (Second Router- Exit interface) sends frame Destiantion- (Server NIC) recieves frames
Response Timeout
Manages how long a device waits when it does not hear a reply from the destination.
Flow control
Manages the rate of data transmission and defines how much information can be sent and the speed at which it can be delievered.
Message Delivery Options
Message delivery may be one of the following methods: -Unicast-one to one communication -Multicast- one to many, typically not all -Broadcast- one to all
Role of the Data link layer addresses: Different IP Networks
EX:PC1 - 192.168.1 Web Server- 172.16.1 When the final destination is remote, Layer 3 will provide layer 2 w/ the local default gateway ip address. Basically, PC1 will send MAC addres of destination to router that then router will comunicate to another router and then send to server.
Network Security Protocols
Secure data to provide authentication, data integrity, and data encryption. Examples of secure protocols include Secure Shell (SSH), Secure Sockets Layer (SSL), and Transport Layer Security (TLS).
Transport -3rd layer TCP/IP Model
Supports communication between various devices across diverse networks.
De-encapsulation
This process moves up the stack -When a layer completes its process, that layer strips off its header and passes it up to the next level to be processed. This is repeated at each layer until it is a data stream that the application can process. -Received as Bits(Bit stream)->Frame->Packets->Segments-> Data (data stream)
Role of the Data Link layer Addresses: Same IP Network NOT vocab
When devices are on the same Ethernet network the data link frame will use the actual MAC address of the destination NIC. -MAC addresses are physically embedded into the Ethernet NIC and are local addressing
Devices on the sameNetwork Not vocab
When devices are on the same network the source and destination will have the same number in the network portion of the address. EX: PC1- 192.168.1.110 FTP Server - 192.168.1.9
Sequencing Messages
the process of numbering the segments so that the message may be reassembled at the destination. *TCP is responsible for sequencing the individual segments.
Service Discovery Protocols
used for the automatic detection of devices or services. Examples of service discovery protocols include Dynamic Host Configuration Protocol (DHCP) which discovers services for IP address allocation, and Domain Name System (DNS) which is used to perform name-to-IP address translation.
Functions of Protocols
-Addressing -Reliablility -Flow control -Sequencing -Error Detection -Application Interface
Communications Protocols (Not vocab)
-All communications are governed by protocols -Protocols are the rules that communications will follow -There rules will vary depending on the protocol
Benifits of using a Layered Model
-Assist in protocol design because protocols that operate at a specific layer have defined information that they act upon and a defined interface to the layers above and below -Foster competition because products from different vendors can work together -Prevent technology or capability changes in one layer from affecting other layers above and below. -Provide a common language to describe networking functions and capabilities.
Message Encoding
-Encoding is the process of converting information into another acceptable form for transmission. -Decoding reverses this process to interpret the information.
HTTP- Hypertext Transfer Protocol
-Governs the way a web server and a web client interact -Defines content and format
Two benefits of Segmenting
-Increases speed: Large amounts of data can be sent over the network without tying up a communications link. -Increases efficiency: Only segments which fail to reach the destination need to be retransmitteed, not the entire data stream
TCP - Transmission Control Protocol
-Manages the individual conversations -Provides guaranteed delivery -Manages flow control
Various types of protocols
-Network communications protocols -Network security Protocols -Routing Protocols -Service Discovery Protocols
Two parts of IP address
-Network portion (IPv4) or Prefix (IPv6) - The left-most part of the address that indicates the network in which the IP address is a member. All devices on the same network will have the same network portion of the address. -Host portion (IPv4) or Interface ID (IPv6) - The remaining part of the address that identifies a specific device on the network. This portion is unique for each device or interface on the network.
Message Formatting and Encapsulation
-When a message is sent, it must use a specific format or structure. -Message formats depend on the type of message and the channel that is used to deliver the message.
Novell NetWare
A short-lived proprietary protocol suite and network operating system developed by Novell Inc. in 1983 using the IPX network protocol. In 1995, Novell adopted TCP/IP to replace IPX.
AppleTalk
A short-lived proprietary protocol suite released by Apple Inc. in 1985 for Apple devices. In 1995, Apple adopted TCP/IP to replace AppleTalk.
TCP/IP layer -> Protocol stack
Application-> HTTP Transport -> TCP Internet -> IP Network Access -> Ethernet
Internet Protocol (IP)
Delievers messages globally from the sender to the receiver
Network Protocol Requirements
Common computer protocols must be in agreement and include the following requirements: -Message encoding -Message formatting and encapsulation -Message size -Message timing -Message delivery options
Ethernet
Delivers messages from one NIC to another NIC on the same Ethernet LAN
Layer 3 Logical Address
Contains two IP address: -Source IP address: The IP address of the sending device, which is the original source of the packet. -Destination IP address - The IP address of the receiving device, which is the final destination of the packet.
Network Access -1st layer TCP/IP Model Layer
Controls the hardware devices and media that make up the network.
Network Communication Protocols
Enable two or more devices to communicate over one or more networks. The Ethernet family of technologies involves a variety of protocols such as IP, transmission Control Protocols (TCP), HyperText transfer Protocols (HTTP) and more
Message Size
Encoding between hosts must be in an appropriate format for the medium. -Mesages sent across the network are converter to bits. -The bits are encoded onto a pattern of light, sound, or electrical impulses. -The destination host must decode the signals to interpret the message.
Internet Research Task Force (IRTF) Internet Standard Organization
Focused on long-term research related to internet and TCP/IP protocols such as Anti-spam research group (ASRG)
International Telecommunications Union-Telecommunication Standardization Sector (ITU-T) Electronic and Communications Standards Organization
One of the largest and oldest communication standards organizations. The ITU-T defines standards for video compression, Internet Protocol Television (IPTV), and broadband communications, such as a digital subscriber line (DSL).
Electronic Industries Alliance (EIA) Electronic and Communications Standards Organization
Organization is best known for its standards relating to electrical wiring, connectors, and the 19-inch racks used to mount networking equipment.
Institute of Electrical and Electronics Engineers (IEEE, pronounced "I-triple-E" (focus on this on) Electronic and Communications Standards Organization
Organization of electrical engineering and electronics dedicated to advancing technological innovation and creating standards in a wide area of industries including power and energy, healthcare, telecommunications, and networking. Important IEEE networking standards include 802.3 Ethernet and 802.11 WLAN standard. Search the internet for other IEEE network standards.
Telecommunications Industry Association (TIA) Electronic and Communications Standards Organization
Organization responsible for developing communication standards in a variety of areas including radio equipment, cellular towers, Voice over IP (VoIP) devices, satellite communications, and more.
Routing Protocols
Protocols enable routers to exchange route information, compare path information, and then to select the best path to the destination network. Examples of routing protocols include Open Shortest Path First (OSPF) and Border Gateway Protocol (BGP).
Rule establishment
Protocols must account for the following requirements.: -An identified sender and receiver -Common language and grammar -Speed and timing of delivery -Confimation or acknowledgement requirements.
Application 4th layer TCP/IP Model
Represents data to the user, plus encoding and dialog control.
Network layer source and destination addresses
Responsible for delivering the IP packet from the original source to the final destination, which may be on the same network or a remote network.
Data link layer source and destination addresses
Responsible for delivering the data link frame from one network interface card (NIC) to another NIC on the same network.
Internet Architecture Board (IAB) Internet Standard Organization
Responsible for the overall mangement and development of internet standards
Internet Society (ISOC) Internet Standard Organization
Resposible for promoting the open development and evolution of internet use throughout the world
PDU- Protocol data unit
The form that a piece of data takes at any layer. (PDU name , TCP layer location) Bits=Physical layer 1 Frames= Data Link Layer 2 Packets= Network Layer3 Segments= Transport layer4 Data = Application layer7
Segmenting
The process of breaking up messages into smaller units
Encapsulation
The process where protocols add their information to the data -This is a top to down process -The level above does its process and then passes it down to the next level of the model. This process is repeated by each layer until it is sent out as a bit stream.
Multiplexing
The processes of taking multiple streams of segmented data and interleaving them together.
Communication Fundamentals (this is not a vocab word
There are three elements to any communication: There will be a source (sender) There will be a destination (receiver) There will be a channel (media) that provides for the path of communications to occur
Application Interface Function of Protocols
This function contains information used for process-to-process communications between network applications. For example, when accessing a web page, HTTP or HTTPS protocols are used to communicate between the client and server web processes.
Error Detection Function of Protocols
This function is used to determine if data became corrupted during transmission. Various protocols that provide error detection include Ethernet, IPv4, IPv6, and TCP.
Reliability Function of Protocols
This function provides guaranteed delivery mechanisms in case messages are lost or corrupted in transit. TCP provides guaranteed delivery.
Sequencing Function of Protocols
This function uniquely labels each transmitted segment of data. The receiving device uses the sequencing information to reassemble the information correctly. This is useful if the data segments are lost, delayed or received out-of-order. TCP provides sequencing services.
Addressing Function of Protocol
This identifies the sender and the intended receiver of the message using a defined addressing scheme. Examples of protocols that provide addressing include Ethernet, IPv4, and IPv6.
Open Systems Interconnection (OSI) protocols
This is a family of protocols developed in 1977 by the International Organization for Standardization (ISO) and the International Telecommunications Union (ITU). The OSI protocol also included a seven-layer model called the OSI reference model. The OSI reference model categorizes the functions of its protocols. Today OSI is mainly known for its layered model. The OSI protocols have latrgely been replaced by TCP/IP
Internet Protocol Suite or TCP/IP
This is the most common and relevant protocol suite used today. The TCP/IP Protocol suite is an open standard protocol suite maintenained by the Internet Engineering Task Force (IETF)
Data Link Layer -2nd layer OSI Model
This layer protocols describe methods for exchanging data frames between devices over a common media
Physical Layer -1st layer OSI Model
This layer protocols describe the mechanical, electrical, functional, and procedural means to activate, maintain, and de-activate physical connections for a bit transmission to and from a network device.
Transport Layer- 4th layer OSI Model
defines services to segment, transfer, and reassemble the data for individual communications between the end devices.
Application Layer- 7th layer OSI Model
layer contains protocols used for process-to-process communications.
Presentation Layer - 6th layer OSI Model
layer provides for common representation of the data transferred between application layer services.
Session Layer- 5th layer OSI Model
layer provides services to the presentation layer to organize its dialogue and to manage data exchange.
Networking Layer - 3rd Layer OSI Model
provides services to exchange the individual pieces of data over the network between identified end devices.
