DMET602 Lecture 2: Network Protocols and Standards

• DMET602 Lecture 2 covers Networks Protocols and Standardization, Network Access: Data Encapsulation and Data Access, and the Physical and Data Link Layers.

Message Delivery Options

• Message delivery occurs via Unicast (one-to-one), Multicast (one-to-many, but typically not all), and Broadcast (one-to-all) methods.
• Broadcasts are only for IPv4 networks, not IPv6; Anycast is an additional option for IPv6 delivery.

Network Protocol Overview

• Protocols can be implemented in software and hardware.
• Protocols have their own Function, Format, and set of Rules.
• Network Communications enable devices to exchange data; Network Security secures data via authentication, data integrity, and encryption
• Routing enables routers to exchange route information, comparing path information to select the best path.
• Service Discovery is automatic device or service detection.

Network Protocol Suites

• Protocols must integrate with each other; A protocol suite is a group of inter-related protocols for communication.
• Protocol suites are sets of rules that work together to solve a problem.
• Lower Layers are concerned with moving data with the Upper Layers providing services.

Protocol Interaction

• Networks use several protocols, each with its own function/format.
• Hypertext Transfer Protocol (HTTP) governs the way a web server and a web client interact by defining content/format.
• Transmission Control Protocol (TCP) manages conversations, guarantees delivery, and manages flow control.
• Internet Protocol (IP) delivers messages from senders to receivers globally.
• Ethernet delivers messages across a Local Area Network (LAN).
• TCP Internet Protocol Suite or TCP/IP protocol is the most common and is maintained by the Internet Engineering Task Force (IETF)
• Open Systems Interconnection (OSI) protocols are developed by the ISO and ITU.
• AppleTalk and Novell NetWare are proprietary suites by Apple Inc. and Novell Inc., respectively.

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.
• TCP/IP is the protocol suite used by the internet, with an open standard freely available to the public and any vendor.
• It is a standards-based protocol suite endorsed by the networking industry and approved by a standards organization to ensure interoperability

TCP/IP Communication Process

• A web server encapsulates and sends a web page to a client.
• A Client de-encapsulates the web page for a web browser.

Standards Organizations

• Open standards encourage Interoperability, competition and innovation
• Open standard organizations are vendor-netural, non-profit organizations that were established to created open standards
• Internet Society (ISOC) promotes open development of the internet, and Internet Architecture Board (IAB) manages internet standards.
• Internet Engineering Task Force (IETF) develops, updates, and maintains internet and TCP/IP technologies with the Internet Research Task Force (IRTF) focused on long-term research.
• Internet Corporation for Assigned Names and Numbers (ICANN) coordinates IP address allocation, domain name management, and other information assignment; overseen/managed by the Internet Assigned Numbers Authority (IANA).
• Institute of Electrical and Electronics Engineers (IEEE) creates power/energy, healthcare, telecommunications, and networking standards.
• Telecommunications Industry Association (TIA) develops communication standards for radio equipment, cellular towers, Voice over IP (VoIP), & satellite communications
• 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)

Benefits of Using a Layered Model

• Layered models are used because complex networks are difficult to understand.
• Models include Open System Interconnection (OSI) and TCP/IP.
• Protocol design is assisted since designed that operate at a specific layer have defined information that they act upon and a defined interface to the layers above an below
• Foster competition is improved since products from different vendors can work together
• Prevent technology or capacity changes in a single layer from affecting other layers above and below
• Provides a common language to describe networking functions
• OSI Model layers from 7 to 1 include: Application, Presentation, Session, Transport, Network, Data Link, and Physical.
• TCP/IP layers include Application, Transport, Internet, and Network Access.

Data Encapsulation

• Encapsulation is a process where protocols add information to data.
• Segmentation is the process of breaking messages into smaller units and Multiplexing interleaves streams of segmented data together.
• Segmentation increases the speed large data goes through a network and minimizes information that has to retransmitted.

Data Sequencing

• Data Sequencing is needed so that segments can be reassembled at the destination.
• Transmission Control Protocol (TCP) handles the sequencing of the segments.

Protocol Data Units (PDU)

• Protocol Data Units (PDUs) at each stage has unique names to reflect new function.

• In the TCP/IP model, PDUs are named according to the protocol suite:

  • Data (Data Stream)
  • Segment
  • Packet
  • Frame
  • Bits (Bit Stream)

• Encapsulation follows a top-down process

• De-encapsulation occurs as data moves up the stack, using processes at each layer that strips off it's header

Data Access Addresses

• Data link and network layers both use addressing to deliver data from source to destination.
• Network layer addresses deliver IP packets from the original source to final destination.
• Data link layer addresses deliver data link frames from one NIC to another NIC on the same network.

Layer 3 Logical Address

• An IP packet contains 2 IP address: Source IP, and Destination IP
• An IP address contains two parts: the network portion/prefix and the host portion, which is unique fo each device in the network

Devices on the Same Network and Remote Networks

• On devices on the same network, the source and destination have the same number of the network portion of the address
• When on the same network, the data link frame uses the actual MAC address of the destination NIC.
• MAC addresses are local, physically embedded in the Ethernet NIC.
• The Source MAC address identifies the originator on the link.
• The Destination MAC address is always be on the same link as the source.

Role of Network and Data Link Layer Addresses on Remote Networks

• Layer 3 provides Layer 2 with DGW(default gateway) or the IP address the router interface
• All devices on the LAN must be told to direct their to the destination.
• Once Layer 2 from PC1 forwards to the default gateway(Router), the router starts the routing to start the process of getting the information to the actual destination
• Data Addressing is local which requires a destination for each link.
• Unlike L3 addressing, L2 local addressing changes for each link or hop.

The Physical Layer

• Standards are implemented in hardware with physical layer standards are governed by many organizations including ISO, EIA, TIA, ITU-T, ANSI, IEEE
• Before any network communications can occur, a physical connection to a local network must be established
• Physical layer transports bits across the network media as the last step on encapsulation.
• Next device in the path receives the bits and re-encapsulates, they decides to do with it.
• Physical Components are the hardware that transmit signals.
• Encoding converts bits into a data stream recognizable by the next device.
• Signalling refers to the method by which bit values are represented on the physical medium

Bandwidth Terminology

• Bandwidth is the rate data can be carried across medium.
• Digital bandwidth measures the amount of data that can flow in a period of time in bits per second(bps).
• 1 kbps =1,000 bps, Mbps = 1,000,000 bps, Gbps - 1,000,000,000bps, Tbps = 1,000,000,000,000 bps
• Latency is the measure of time for data to travel from one point to another with delays.
• Throughput is the measure of bits transfered, but is less than bandwidth because of overhead
• Goodput is throughput minus overhead

Data Link Layer

• Data link layer is responsible for communications between end-device network interface cards.
• Allows upper layer protocols to access the physical media and encapsulated Layer 3 packets, preforms error detection and rejects corrupt frames.
• Two sublayers include Logical Link Control (LLC) and Media Access Control (MAC)
• The LLC sublayer communicates with network layer and identifies the protocol, MAC defines the media access processes performed by the hardware
• The MAC sublayer provides access to various network technology.

Topology

• Media access control is the equivalent of traffic rules that regulate a the motor entrance to the road.
• Common physical WAN topologies include: the Point-to-point, Hub ad spoke, Mesh
• LAN's are typically interconnected using a star and extended star topology
• End devices on LANs require scalable and and easy troubleshooting
• Bus - End systems chained together with bus and ring topology.

Half and Full Duplex Communication

• Half-duplex limits access to one device send or receive at a time, used on WLAN and Ethernet hubs.
• Full-duplex allows both devices to communicate transmits, Ethereal and switches operate in full duplex
• Media Access Contol methods include Contention and Controlled Based access
• Contention based access includes nodes that operators in half of duplex with only one can send at a time, examples include CSMA/CD and SM/CA

Media Access Control Methods

• Carrier Sense Multiple Access / Collision Detection (CSMA/CD) process is used in half-duplex Ethernet LANs, but there are collisions will occur if 2 frames meet at the same time.

Data Link Frame

• Data are encapsulated by a data link layer with a header and trailer with data, header, and trailer parts.
• These include Frame start and stop, addressing, type, control error
• Also referred to as physical Address are contained within header and are used for local delivery with different types of frames.
• The logical topology and physical media determine how data is linked.
• Common frames are eternet, 802.11 wireless, point to point (PPP) and Frame Relay
• Media access controls are made for logical topologies.

Lecture 2 of DMET602 discusses network protocols, standards, and access methods. It also contrasts message delivery methods like Unicast, Multicast, and Broadcast. The lecture touches on network communication, security, and routing.