Week 2 Protocols and Models.docx

**Week 2 Protocols and Models** **The Rules** **Communications Fundamentals** - Networks can vary in size and complexity. It is not enough to have a connection device must agree on "how" to communicate. - There will be a source (sender) - There will be a destination (receiver)...

**Week 2 Protocols and Models** **The Rules** **Communications Fundamentals** - Networks can vary in size and complexity. It is not enough to have a connection device must agree on "how" to communicate. - 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 **Communication Protocols** - All communications are governed by protocols. - Protocols are the rules that communications will follow - These rules will vary depending on the protocol A screenshot of a computer Description automatically generated **Rule Establishment** - Individuals must use established rules or agreements to govern conversation. - Protocols must account for the following requirements: - An identified sender and receiver - Common language and grammar - Speed and timing of delivery - Confirmation or acknowledgment requirements **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 **Message Encoding** - Encoding is the process of converting information into another acceptable form for transmission. - Decoding reverses this process to interpret the information. **\ 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. *IP HEADER: A packet header is a \"label\" of sorts, which provides information about the packet\'s contents, origin, and destination.*  **Message Size** - Encoding between hosts must be in appropriate format for the medium. - Messages sent across the network are converted to bits - The bits are encoded into a pattern of light, sound, or electrical impulses. - The destination host must decode the signals to interpret the message **Message Timing** - Message timing includes the following: - **Flow Control** -- Manages the rate of data transmission and defines how much information can be sent and the speed at which it can be delivered. - **Response Timeout** -- Manages how long a device waits when it does not hear a reply from the destination - **Access Method** -- Determines when someone can send a message. **\ ** **Message Delivery Options** - Message delivery may one of the following methods: - **Unicast --** one to one communication - **Multicast --** one to many, typically not all - **Broadcast** -- one to all ***Note:** Broadcast are used in IPv4 networks but are not an option for IPv6.* A computer network diagram with blue and yellow computers Description automatically generated **A Note About the Node Icon** - Documents may use the node icon, typically a circle, to represent all devices. - The figure illustrates the use of the node icon for delivery options. **\ ** **Protocols** **Network Protocol Overview** - Network protocols define a common set of rules. - Can be implemented on devices in: - Software - Hardware - Both - Protocols have their own: - Function - Format - Rules **Protocol Type** **Description** ------------------------ ---------------------------------------------------------------------------------------------- Network Communications Enable two or more devices to communicate over one or more networks Network Security Secure data to provide authentication, data integrity, and data encryption Routing Enable routers to exchange route information, compare path information, and select best path Service Discovery Used for the automatic detection of devices or services **Network Protocol Functions** - Devices use agreed-upon protocols to communicate. - Protocols may have one or more functions **Function** **Description** ----------------------- ---------------------------------------------------------------- Addressing Identifies sender and receiver Reliability Provides guaranteed delivery Flow Control Ensures data flows at an efficient rate Sequencing Uniquely labels each transmitted segment of data Error Detection Determines if data became corrupted during transmission Application Interface Process -- process communications between network applications **\ ** **Protocol Interaction** - Networks require the use of several protocols. - Each protocol has its own function and format. +-----------------------------------+-----------------------------------+ | **Protocol** | **Function** | +===================================+===================================+ | Hypertext Transfer Protocol | - Governs the way a web and a | | (HTTP) | web client interact | | | | | | - Defines content and format | +-----------------------------------+-----------------------------------+ | Transmission Control Protocol | - Manges the individual | | (TCP) | conversations | | | | | | - Provides guaranteed delivery | | | | | | - Manages flow control | +-----------------------------------+-----------------------------------+ | Internet Protocol (IP) | - Delivers messages globally | | | from the sender to the | | | receiver | +-----------------------------------+-----------------------------------+ | Ethernet | - Delivers message from one | | | NIC(Network Interface Card) | | | to another NIC on the same | | | Ethernet Local Area Network | | | (LAN) | +-----------------------------------+-----------------------------------+ **Protocol Suites** **Network Protocol Suites** - Protocols must be able to work with other protocols. - Protocol Suite: - A group of inter-related protocols necessary to perform a communication function - Sets of rules that work together to help solve a problem - The protocols are viewed in terms of layers: - Higher Layers - Lower Layers -- concerned with moving data and provide services to upper layers. A diagram of two people Description automatically generated **Evolution of Protocol Suites** - There are several protocol suites. - **Internet Protocol Suite or TCP/IP** - The most common protocol suite and maintained by the Internet Engineering Task Force (IETF) - **Open Systems Interconnection (OSI) protocols** - Developed by the International Organization for Standardization (ISO) and the International Telecommunications Union (ITU) - **AppleTalk** - Proprietary suite release by Apple Inc. - **Novell Netware** - Proprietary suite developed by Novell Inc. **TCP/IP Protocol Example** - TCP/IP protocols operate at the application, transport, and internet layers. - The most common network access layer LAN protocols are Ethernet and WLAN (wireless LAN). A computer screen shot of a cloud Description automatically generated **TCP/IP Protocol** **Suite** - TCP/IP is the protocol suite used by the internet and includes many protocols. - TCP/IP is: - An open standard protocol suite that is freely available to the public and can be used by any vendor - A standards-based protocol suite that is endorsed by the networking industry and approved by a standards organization to ensure interoperability. **TCP/IP Communication Process** - A web server encapsulation and sending a web page to a client.A computer screen shot of a computer Description automatically generated - A client de-encapsulating the web page for the web browser.  **Reference Models** **The Benefits of Using a Layered Model** - Complex concepts such as how a network operates can be difficult to explain and understand. For this reason, a layered model is used. - Two Layered models describe network Operations: - **Open System Interconnection (OSI) Reference Model** **OSI Model Layer** **Description** --------------------- ------------------------------------------------------------------------------------------------ APPLICATION Contains protocols used for process -- to process communications PRESENTATION Provides for common representation of the data transferred between application layer services. SESSION Provides services to the presentation layer and to manage data exchange. TRANSPORT Defines services to segment, transfer, and reassemble the data for individual communications NETWORK Provides services to exchange the individual pieces of data over the network. DATA LINK Describes methods for exchanging PHYSICAL Describes the means to activate, maintain and de-activate physical connections. - **TCP/IP Reference Model** **TCP/IP Model Layer** **Description** ------------------------ ------------------------------------------------------------------------- APPLICATION Represents data to the user, plus encoding and dialog control. TRANSPORT Supports communication between various devices across diverse networks. INTERNET Determines the best path through the network. NETWORK ACCESS Controls the hardware devices and media that make up the network. Other benefits 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 **OSI and TCP/IP Model Comparison** - The OSI model divides the network access layer and the application layer of the TCP/IP model into multiple layers. - The TCP/IP protocol suite does not specify which protocols to use when transmitting over a physical medium. - OSI Layers 1 and 2 discuss the necessary procedures to access the media and the physical means to send data over a network **Data Encapsulation** **[Segmenting Messages]** - **Segmenting** -- the process of breaking up messages into smaller units. - **Multiplexing** -- the processes of taking multiple streams of segmented data and interleaving them together. - **Increases speed --** Large amounts of data can be sent over the network without typing up a communications link. - **Increases efficiency** -- Only segments which fail to reach the destination need to be retransmitted, not the entire data stream. **[Sequencing]** - **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. **[Protocol Data Units (PDU)]** - **Encapsulation** -- the process where protocols add their information to the data - At each stage of the process, a PDU has a different name to reflect its new functions. - There is no universal naming convention for PDUs, in this course, the PDUs are named according to the protocols of the TCP/IP suite. - PDUs passing down the stack are as follows: - Data (Data Stream) - Segment - Packet - Frame - Bits (Bit Stream  **Encapsulation Example :** - Encapsulation is a top-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. A computer screen shot of a diagram Description automatically generated **De-encapsulation Example:** - Data is de-encapsulated as it 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 - Packet - Segment - Data (Data Stream  **\ ** **Data Access** **Addresses** - Both the data link and network layers use addressing to deliver data from source to destination. - **Network layer source and destination addresses** - Responsible for delivering the IP packet from original source to the final destination. - **Data link layer source and destination addresses** - Responsible for delivering the data link frame from one NIC to another NIC on the same network. A diagram of a network Description automatically generated **Layer 3 Logical Address** - The [IP packet] contains two IP addresses: - **Source IP address** - The IP address of the sending device, original source of the packet. - **Destination IP address** - The IP address of the receiving device, final destination of the packet. - The IP address contains two parts: - **Network portion (IPv4) or Prefix (IPv6)** - The left-most part of the address indicates the network group which the IP address is a member. - Each LAN or WAN will have the same network portion. - **Host portion (IPv4) or Interface ID(IPv6)** - The remaining part of the address identifies a specific device within the group - This portion is unique for each device on the network.  **Devices on the Same Network** - When devices are on the same network, the source and destination will have the same number in network portion of the address. - PC1 -- [192.168.1.110] - FTP Server -- [192.168.1.9] **Role of the Data Link Layer Addresses: Same IP Network** - 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. - The Source MAC address will be that of the originator on the link - The Destination MAC address will always be on the same link as the source, even if the ultimate destination is remote. A diagram of a computer network Description automatically generated ***\ *** **Role of the Network Layer Addresses** - When the source and destination have a different network portion, this means they are on different networks. **Role of the Data Link Layer Addresses: Different IP Networks** - When the final destination is remote, [Layer 3 will provide Layer 2 with the local default gateway IP address, also known as the router address.] - The default gateway (DGW) is the router interface IP address that is part of this LAN and will be the "door" or "gateway" to all other remote locations. - All devices on the LAN must be told about this address or their traffic will be confined to the LAN only. - Once Layer 2 on PC1 forwards to the default gateway (Router), the router then can start the routing process of getting the information to actual destination. - The data link addressing is local addressing so it will have a source and destination for each link. - The MAC addressing for the first segment is: - Source -- AA-AA-AA-AA-AA-AA. (PC1) sends the frame. - Destination -- 11-11-11-11-11-11 (R1-Default Gateway MAC) receives the frame. **\ ** **Data Link Addresses** - Since data link addressing is local addressing, it will have a source and destination for each segment or hop of the journey to the destination. MAC addressing for the first segment: - Source -- (PC1 NIC) sends frame - Destination -- (First Router -- DGW interface) Receives frame  MAC addressing for the second segment: - Source -- (First Router -- exit interface) sends frame - Destination -- (Second Router) receives frame A diagram of a computer Description automatically generated MAC addressing for the last segment - Source -- (Second Router -- exit interface) sends frame - Destination -- (Web Server NIC) receives frame  - Notice that packet is not modified, but the frame is changed, therefore the L3 IP addressing does not change from segment to segment like the L2 MAC addressing. - The L3 addressing remains the same since it is global and the ultimate destination is still the Web Server. A diagram of a computer program Description automatically generated **Standards Organization** **Open Standards** Open standards encourage: - interoperability - competition - innovation - vendor-neutral - non-profit organizations - established to develop and promote the concept of open standards **Internet Standards** - **Internet Society (ISOC)** - Promotes the open development and evolution of internet. - **Internet Architecture Board** - Responsible for management and development of internet standards - **Internet Engineering Task Force(IETF)** - Develops, updates, and maintains internet and TCP/IP technologies - **Internet Research Task Force (IRTF)** - Focused on long-term research related to internet and TCP/IP protocols Standards organizations involved with the development and support of TCP/IP - **Internet Corporation for Assigned Names and Numbers (ICANN)** - Coordinates IP address allocation, the management of domain names, and assignment of other information - **Internet Assigned Numbers Authority (IANA)** - Overseas and manages IP address allocation, domain name management, and protocol identifiers for **\ ** **Electronic and Communications Standards** - **Institute of Electrical and Electronics Engineers (IEEE)** - dedicated to creating standards in power and energy, healthcare, telecommunications, and networking - **Electronic Industries Alliance (EIA)** - develops standards relating to electrical wiring, connectors, and the 19-inch racks used to mount networking equipment - **Telecommunications Industry Association (TIA)** - develops communication standards in radio equipment, cellular towers, Voice over IP (VoIP) devices, satellite communications, and more - **International Telecommunications Union-Telecommunication Standardization Sector (ITU-T)** - defines standards for video compression, Internet Protocol Television (IPTV), and broadband communications, such as a digital subscriber line (DSL). ***\ *** **IP HEADER** **TCP/IP Model** **NETWORK (IP) -** **DATALINK (ethernet) --** MAC(Media Access Control Address) 00:d9:w2:D9:p9:00 **PHYSICAL --** cables, bits,bytes