Protocols and Models Flashcards
What are the three main elements of communication methods?
1) Message source: sender
2)Message destination:receiver, the destination receives the message and analyzes it
3)Channel: media which provides the message’s pathway
What should the devices do prior to communicating?
Must agree on how to communicate and must also format he message in an understandable way
What are the requirements protocols must account for in order to successfully send a message that is understood by the receiver?
1) An identified sender and receiver
2) Common language and grammar
3) Speed and timing of the delivery
4) Confirmation or acknowledgement requirements
What are the requirements computer protocol include?
1) Message encoding
2) Message formatting and encapsulation
3) Message size
4) Message timing
5) Message delivery options
Explain message encoding
Encoding is the process of converting information into another acceptable form. Decoding reverses this process to interpret the information.
Encoding between hosts must be in an appropriate format for the medium, messages sent into the network are first converted into bits by the host. Each bit is encoded into patterns of voltages on copper wires, infrared lights in optical fibers or microwaves for wireless systems. The destination host receives and decodes the signal to interpret the message.
Explain message format and encapsulation
Message format depend on the type of message, and the channel that is used to deliver the message.
A message that is sent over a computer needs to follow specific format rules in order to be delivered.
IPv6 identifies the source of the packet and it’s destination.
IP is responsible for sending a message from message source to destination over one or more networks.
Explain message size
The size restrictions (very strict) of frames require the source host to break a long message into individual pieces to that meets size requirements. The long message will e sent in separate frames, each contain a piece of the original message and its own addressing info. At the destination host, the individual pieces of messages will be reconstructed into the original message.
Note: Rules also depend on the channel used
Explain message timing
1) Flow Control
2) Response Time out
3) Access Method
Explain flow control
The process of managing the rate of data transmission. Flow control defines how much data can be sent and the speed at which it an be delivered. In network communication, there are network protocols used by the source and destination devices to negotiate and manage the flow of information.
Explain Response Time out
Hosts on the network use network protocols that specify how long to wait for responses and what action to take if a response timeout occurs.
Explain Access method
This determines when someone can send a message. When a device wants to transmit on a wireless LAN, it is necessary for the WLAN network interface card (NIC) to determine whether the wireless medium is available.
Explain message delivery options
1) Unicast - Information is being transmitted to a single end device.
2) Multicast - Information is being transmitted to a one or more end devices.
3) Broadcast - Information is being transmitted to all end devices.
Explain Node Icon
Networking documents and topologies often represent networking and end devices using a node icon. Nodes are typically represented as a circle.
Define Network Protocols
a common format and set of rules for exchanging messages between devices.
They are implemented by end devices and intermediary devices in software, hardware or both.
What are the protocols needed to enable communications across one or more networks?
1) Network Communication Protocols
2) Network Security Protocols
3) Routing Protocols
4) Service Discovery Protocols
Define Network Communication Protocols
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 Protocol (TCP), HyperText Transfer Protocol (HTTP)…
Define Network Security Protocols
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).
Define 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).
Define Service Discovery Protocols
Protocols are 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.
What are the functions of the agreed-upon protocols that are used to communicate between computers and network devices?
1) Addressing
2) Reliability
3) Flow Control
4) Sequencing
5) Error Detection
6) Application Interface
Define Addressing
Identifies the sender and the intended receiver of the message using a defined addressing scheme (Ethernet, IPv4, and IPv6)
Define Reliability
This function provides guaranteed delivery mechanisms in case messages are lost or corrupted in transit (TCP)
Define Flow control
This function ensures that data flows at an efficient rate between two communicating devices (TCP)
Define Sequencing
Uniquely labels each transmitted signal 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
Define Error Detection
This function is used to determine if data became corrupted during transmission (Ethernet, IPv4, IPv6, and TCP)
Define Application Interface
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.
Define HTTP
Hyper Text Transfer Protocol; governs the way a web server and a web client interact, it defines the content and formatting of the requests and responses that are exchanged between the client and the server. Both the client and the web server implement HTTP as a part of the application. HTTP relies on the protocols to govern how the messages are transported between the client and server.
Define TCP
Transmission Control Protocol; manages the individual conversations, it is responsible for the reliable delivery of the information and managing flow control between the end devices.
Define IP
Internet Protocol; responsible for delivering messages from sender to receiver, it’s also used in routers to forward the message across multiple networks.
Define Ethernet
Responsible for the delivery of messages from one NIC to another on the same Ethernet local area network (LAN)
Define Protocol Suites
A protocol suite is a group of inter-related protocols necessary to perform a communication function.
Define a protocol stack
shows how the individual protocols within a suite are implemented. The protocols are viewed in terms of layers, with each higher-level service depending on the functionality defined by the protocols shown in the lower levels. The lower layers of the stack are concerned with moving data over the network and providing services to the upper layers, which are focused on the content of the message being sent.
In the middle is the rules layer that stipulates the requirements of communication including that a common language must be chosen. At the top is the content layer and this is where the content of the communication is actually spoken.
Define Internet Protocol Suite (TCP/IP)
An open standard protocol suite maintained by the Internet Engineering Task Force.
Define the ISO protocols
Open Systems Interconnections Protocol
Includes a seven-layer model called the ISO reference model. It categorizes the functions of its protocols. Its replaced by TCP/IP
Which layers are TCP/IP protocols available for?
Application
Transport
Internet
There are no protocols for Network access layer
What are the most common network access layers?
LAN protocols are Ethernet and WLAN (wireless LAN) protocols
What are the two important aspects for vendors and manufacturers?
1) Open standard protocol suite: it’s freely available to the public and can be used by any vendor on their hardware or software.
2) Standard-based protocol suite: it has been endorsed by the networking industry and approved by a standards organization. This ensures that the products from different manufacturers can interoperate successfully.
What are the layers of the TCP/IP protocol suite?
1) Network Access Layer
2) Internet Layer
3) Transport Layer
4) Application Layer
Talk about Network Access Layer
1) Address Resolution
a) ARP: address resolution protocol, provides dynamic access mapping between IPv4 address and hardware address
2) Data Link Protocols
a) Ethernet: defines the rules for wiring and signaling standards in the network access layer
b)WLAN: defines the rules for wireless signaling across 2.4 GHz and 5 GHz radio frequencies.
What are the three protocols in the Internet Layer?
1) Internet Protocol
2) Messaging
3) Routing Protocol
Talk about Internet Protocol
1) IPv4: Internet protocol version 4. Receives message segments from the transport layer, packages messages into packages, and addresses packages for end-to-end delivery on a network. IPv4 uses a 32-bit address.
2) IPv6: similar to IPv4 but uses a 128-bit address.
3) NAT: Network Address Translation; Translates IPv4 addresses from a private network into globally unique public IPv4 addresses.
Talk about Messaging
1) ICMPv4: Internet Control Message Protocol for IPv4; Provides feedback from a destination host to a source host about errors in-packet delivery.
2) ICMPv6: Similar functionality to ICMPv4 but for IPv6.
ICMPv6 ND: ICMPv6 Neighbor Discovery; Includes four protocols that are used for address resolution and duplicate address detection.
Talk about Routing Protocols
1) OSPF: Open Shortest Path First; The link-state routing protocol uses a hierarchical design based on areas. It’s an open standard interior routing protocol
2) EIGRP: Enhanced Interior Gateway Routing Protocol; An open standard routing protocol developed by Cisco uses a composite metric based on bandwidth, delay, load, and reliability.
3) BGP: Boarder Gateway Protocol; An open standard exterior gateway routing protocol used by internet service providers (ISPs). BGP is also commonly used between ISPs and their large private clients to exchange routing information.
Talk about Transport Layer
1) Connection Oriented:
TCP: Transmission Control Protocol; Enables reliable communication between processes running on different hosts and provides reliable, acknowledged transmissions that confirm successful delivery.
2) Connectionless:
UDP: User Datagram Protocol; Enables a process running on a host to send packets to a process running on a different host. However, UDP does not confirm successful datagram transmission.
Talk about Application Layer
1) DNS
2) Host Config
3) E-mail
4) File Transfer
5) Web and Web services
Talk about DNS
Domain Name System: responsible for name-to-IP translation.
Talk about Host Config
1) DHCPv4: Dynamic Host Configuration Protocol for IPv4. A DHCPv4 server dynamically assigns IPv4 addressing information to DHCPv4 clients at start-up and allows the addresses to be re-used when no longer needed.
2) DHCPv6: A DHCPv6 server dynamically assigns IPv6 addressing information to DHCPv6 clients at start-up.
SLAAC: Stateless Address Auto Configuration; allows a device to obtain it’s IPv6 addressing information without using a DHCPv6 server.
Talk about E-mail
- SMTP - Simple Mail Transfer Protocol. Enables clients to send email to a mail server and enables servers to send email to other servers.
- POP3 - Post Office Protocol version 3. Enables clients to retrieve email from a mail server and download the email to the client’s local mail application.
- IMAP - Internet Message Access Protocol. Enables clients to access email stored on a mail server as well as maintain email on the server.
Talk about File Transfer
- FTP - File Transfer Protocol. Sets the rules that enable a user on one host to access and transfer files to and from another host over a network. FTP is a reliable, connection-oriented, and acknowledged file delivery protocol.
- SFTP - SSH File Transfer Protocol. As an extension to Secure Shell (SSH) protocol, SFTP can be used to establish a secure file transfer session in which the file transfer is encrypted. SSH is a method for secure remote login that is typically used for accessing the command line of a device.
- TFTP - Trivial File Transfer Protocol. A simple, connectionless file transfer protocol with best-effort, unacknowledged file delivery. It uses less overhead than FTP.
Talk about Web and Web server
Web and Web Service
* HTTP - Hypertext Transfer Protocol. A set of rules for exchanging text, graphic images, sound, video, and other multimedia files on the World Wide Web.
* HTTPS - HTTP Secure. A secure form of HTTP that encrypts the data that is exchanged over the World Wide Web.
* REST - Representational State Transfer. A web service that uses application programming interfaces (APIs) and HTTP requests to create web applications.
