Unit 2 - Networking LO1 Part 2 Last Week Questions Part 1 1. True or False: The biggest difference between a LAN and WAN is usually the size of the network? 2. What network model offers no centralized storage of data or centralized control over the sharing of files or resources? 3. In what networking model is the processing power shared between the client systems and the server? Last Week Questions Part 2 What is the maximum number of computers recommended for inclusion in a peer-to-peer network?
A. 2 B. 5 C. 10 D. 25 When a WAN is confined to a certain geographic area, such as a university campus or city, it is known as a A. LAN B. MAN Networking topology A topology refers to a networks physical and logical
layout. A networks physical topology refers to the actual layout of the computer cables and other network devices. A networks logical topology refers to the way in which the network appears to the devices that use it. Physical topology include star, ring, bus, mesh, tree, ring. Logical topology include Ethernet and Token Ring. Logical topology: Ethernet Most widely used network topology/protocol. Works with the physical bus and star topologies.
Uses coax, twisted-pair, or fibre optic cabling. Uses CSMA/CD (Carrier Sense Multiple Access with Collision Detection) (Well come back to this later). This works by: 1. Systems use the transmission medium known as multiple access by listening until no signals are detected which is known as carrier sense. 2. No signal detected? They transmit and check to see if more than one signal is present which is known as collision detection. 3. Each station attempts to transmit when it "believes" the network is free. 4. Collision detected? Each system will receive a jam signal and try retransmitting after a delay, which is different for Ethernet is also
known as the IEEE 802.3 standard. Logical topology: Token Ring An IBM-proprietary token-passing LAN topology/protocol Defined by IEEE standard 802.5. (See table later on) It operates at either 4Mbps or 16Mbps in a physical star topology In a token ring network, a multistation access unit (MSAU) is equivalent to a hub or switch on an Ethernet network. The MSAU internally performs the token circulation. To create the complete ring, the ring in (RI) port on each MSAU is connected
to the ring out (RO) port on another MSAU. The last MSAU in the ring is then connected to the first to complete the ring. MSAU Logical topology: Token Ring Multistation access unit (MSAU) example setup Physical topology: Bus Uses a trunk or backbone to connect all the computers on the network. Systems connect to this backbone using T connectors or taps (known as a vampire tap, if you must pierce the wire). To avoid signal reflection, a physical bus topology requires that each end of the physical bus be terminated, with one end
also being grounded. A hub or switch is not needed in this installation. Uses coaxial or Ethernet (RJ-45) Cable Terminater T connector BNC connectors used with coaxial cables Physical topology: Bus The most common implementation of a linear bus is the IEEE 802.3(Ethernet) standard Loose or missing terminators from a bus network disrupt data transmissions. Advantages Disadvantages
Compared to other topologies, a bus is cheap and easy to implement. Requires less cable than other topologies. Expansion to the network can cause disruption. Does not use any specialized network equipment. Because all systems on the network connect to a single backbone, a break in the cable prevents all systems from accessing the network. Difficult to troubleshoot. Physical topology: Star All computers and other network devices connect to a central device called a hub or switch. Each connected device requires
a single cable to be connected to the hub, creating a point-topoint connection between the device and the hub. Using a separate cable to connect to the hub or switch allows the network to be expanded without disruption. A break in any single cable does not cause the entire network to fail. The star topology is the easiest to expand in terms of the number of devices connected to the network. Physical topology: Star Most widely implemented network design in use today, but it is not without shortcomings. Because all devices connect to a centralized hub or switch, this creates a single point of failure for the network. Advantages
Disadvantages Star networks are easily expand without disruption to the network Requires more cable than most of the other topologies. Cable failure affects only a single user. A central connecting device enables a single point of failure. Easy to troubleshoot and implement. Requires additional networking equipment to create the network layout. Physical topology: Tree Also known as a star-bus topology Hybrid of a bus and star
topology Star networks are interconnected via bus networks Each node within the network can have any number of child nodes Uses a main hub which is the most active terminal, it controls the whole network, while the subsidiary hubs are passive. An example would be a Cable TV network, with the main feed cable getting divided into smaller branches, which ultimately reach homes. Point-to-point:
Physical topology: Tree Divides the whole network into parts, that are easily manageable. Best topology for very large networks Advantages Disadvantages Easily scalable by adding new nodes Requires a lot of maintenance A simple point to point wiring to the central hub at each intermediate node of a tree topology represents a node in the bus topology Huge cabling is needed Hierarchical networks are not affected if one of them gets damaged Dependence of the entire network on
one central hub is a point of vulnerability for this topology. Easier maintenance and fault finding Meaning 2 devices communicating together. E.g a phone call. Physical topology: Ring Data travels in a circular fashion from one computer to another on the network. It is not a physical ring topology.(Meaning it wont necessarily look like a circle) In a true ring topology, if a single computer or section of cable fails, the signal is interrupted. The entire network becomes
inaccessible. Physical topology: Ring Advantages Cable faults are easily located, making troubleshooting easier. Ring networks are moderately easy to install. Disadvantages Expansion to the network can cause disruption. A single break in the cable can disrupt the entire network. Physical topology: Mesh A unique network design in which each computer on the network connects to every other, creating a point-to-point connection between every device on the network.
Provides a high level of redundancy. If one network cable fails, the data always has an alternative path to get to its destination each node can act as a relay. Complicated wiring. High cabling cost. Troubleshooting a failed cable can be tricky. Not the first choice for many wired networks but is more popular with servers or routers. Physical topology: Mesh Because of the redundant connections,
the mesh topology offers better fault tolerance than other topologies. Advantages Disadvantages Provides redundant paths between LAN topologies. The network can be expanded without disruption to current users. Requires more cable than the other devices Complicated implementation Complete Topology quiz Complete You the 4 question quiz have 20mins to research and complete
Research and explore Role of networks: Consider purpose, benefits, resource implications, communications, working practice, commercial opportunity, information sharing, collaboration. System types: Consider Peer-based, client-server, cloud, cluster, centralised, virtualised. Research and find out advantages and disadvantages to the different types Topology: Logical e.g. Ethernet, Token Ring; physical e.g. star, ring, bus, mesh, tree, ring. Practical While completing this research: Find a suitable PC preferably with 2GB or better RAM Install Windows
Server from provided USBs Unit 2 Assignment 1 is officially launched today and available to read on Moodle. Networking Models For networking, two models commonly are referenced: the OSI model and the TCP/IP model. Both offer a framework, theoretical and actual, for how networking is implemented. The OSI Seven-Layer Model The TCP/IP Four-Layer Model OSI (Open Systems Interconnect) Model One of the most important networking concepts to understand is the OSI
reference model. This conceptual model, created by the International Organization for Standardization (ISO) in 1978 and revised in 1984, describes a network architecture that enables data to be passed between computer systems. The OSI model allows us to think about our network in chunks or layers. You can focus on securing each layer, optimizing each layer, and troubleshooting each layer. Note The TCP/IP model performs the same functions, but predates OSI, and does so in only four layers.
Layer 1. Physical Layer The physical layer identifies the networks physical characteristics, including the following specifications: Hardware: The type of media used on the network, such as type of cable, type of connector, and pinout format for cables. Topology: The physical layer identifies the topology to be used in the network. Common topologies include ring, mesh, star, and bus. This layer also defines the voltage used on a given medium and the frequency at which the signals that carry the data operate. These characteristics dictate the speed and bandwidth of a given medium, as well as the maximum distance over which a certain media type can be used.
Layer 2. Data Link Layer Responsible for getting data to the physical layer so that it can transmit over the network. Error detection, error correction, and hardware addressing. The term frame describes the logical grouping of data at the data link layer. The data link layer has two distinct sublayers:
Media Access Control (MAC) layer: The MAC address is defined at this layer. The MAC address is the physical or hardware address burned into each network interface card (NIC). The MAC sublayer also controls access to network media. The MAC layer specification is included in the IEEE 802.1 standard. Logical Link Control (LLC) layer: Responsible for the error and flowcontrol mechanisms of the data link layer. The LLC layer is specified in the IEEE 802.2 standard. Layer 3: Network Layer The primary responsibility of the network layer is routingproviding mechanisms by which data can be passed from one network system to another. The network layer does not specify how the data is passed, but rather provides the mechanisms to do so. Functionality at the network layer is
provided through routing protocols, which are software components. Protocols at the network layer are also responsible for route selection, which refers to determining the best path for the data to take throughout the network. In contrast to the data link layer, which uses MAC addresses to communicate on the LAN, network layer protocols use software configured addresses and special routing protocols to communicate on the network. The term packet describes the logical grouping of Layer 4: Transport Layer The basic function of the transport layer is to provide mechanisms to transport data between network devices. Primarily it does this in three ways:
Error checking: Protocols at the transport layer ensure that data is correctly sent or received. . Service addressing: Protocols such as TCP/IP support many network services. The transport layer ensures that data is passed to the right service at the upper layers of the OSI model. . Segmentation: To traverse the network, blocks of data need to be broken into packets of a manageable size for the lower layers to handle. Network protocols Formal standards and policies comprised of rules, procedures and formats that define communication between two or more devices over a network.
Layer 5: Session Layer Responsible for managing and controlling the synchronization of data between applications on two devices. It does this by establishing, maintaining, and breaking sessions. Whereas the transport layer is responsible for setting up and maintaining the connection between the two nodes, the session layer performs the same function Layer 6: Presentation Layer Converts data intended for or received from the application layer into another format.
Such conversion is necessary because of how data is formatted so that it can be transported across the network. Applications cannot necessarily read this conversion. Encryption and decryption also takes place on this layer Some common data formats handled by the presentation layer include the following: Graphics files: JPEG, TIFF, GIF, and so on are graphics file formats that require the data to be formatted in a certain way. Text and data: The presentation layer can translate data into different formats, such as ASCII and EBCDIC. Sound/video: MPEG, MP3, and MIDI files all have their own data formats to and from which data must be converted. Layer 7: Application Layer In simple terms, the function of
the application layer is to take requests and data from the users and pass them to the lower layers of the OSI model. Incoming information is passed to the application layer, which then displays the information to the users. Some of the most basic application-layer services include file and print capabilities. OSI Model Summary OSI Layer Major Function Physical (Layer 1) Defines the physical structure of the network and the topology. Data link (Layer 2) Provides error detection and correction. Uses two distinct sublayers:
Media Access Control (MAC) and Logical Link Control (LLC) layers. Identifies the method by which media are accessed. Defines hardware addressing through the MAC sublayer. Network (Layer 3) Handles the discovery of destination systems and addressing. Provides the mechanism by which data can be passed and routed from one network system to another. Transport (Layer 4) Provides connection services between the sending and receiving devices and ensures reliable data delivery. Manages flow control through buffering or windowing. Provides segmentation, error checking, and service identification. Session (Layer 5) Synchronizes the data exchange between applications on separate devices. Presentation (Layer 6) Translates data from the format used by applications into one that can be transmitted across the network. Handles encryption and decryption of data. Provides compression and decompression functionality. Formats data from the application layer into a format that can be sent over the network. Application (Layer
Provides access to the network for applications. Mapping Network Devices Device Hub Bridge Switch Router NIC Access point (AP) OSI Layer Physical (Layer 1) Data link (Layer 2) Data link (Layer 2) or network (Layer 3) Network (Layer 3) Data link (Layer 2) Data link (Layer 2) The TCP/IP Four-Layer Model (Transmission Control Protocol/Internet Protocol)
The OSI model does a fantastic job to outline how networking should occur and the responsibility of each layer. Unfortunately, TCP/IP predates this model and has to perform the same functionality with only four layers. The Application layer enables any number of protocols to be plugged in, such as HTTP, SMTP, SNMP, DNS, and many others. The Transport layer is where TCP and its counterpart UDP operates. The Internet layer is where IP runs (along with ICMP, ARP, and others). The Network Interface layer is sometimes referred to as the Network Accessor Link layer and this is where Ethernet, FDDI, or any other physical technology can run.
Complete Models quiz Complete Have You the 4 question quiz. a go at the bonus questions have 15mins to research and complete Networking Standards Ensure interoperability of networking technologies by defining the rules of communication among networked devices. Help ensure products of different vendors are able to work together in a network without risk of incompatibility. Subcommittees are assigned to deal with and design specific standards
Phones and computers couldnt connect to the same network unless they were all the same or made by the same manufacturer. The Institute of Electrical and Electronics Engineers (IEEE) The Institute of Electrical and Electronics Engineers (IEEE) developed a series of networking standards to ensure that networking technologies developed by respective manufacturers are compatible. This means that the cabling, networking devices, and protocols are all interchangeable when designed under the banner of a specific IEEE standard. IEEE 802 Networking Standards Specificati on Name 802.1
Internetworking 802.2 The LLC (Logical Link Control) sublayer 802.3 CSMA/CD (Carrier Sense Multiple Access with Collision Detection) for Ethernet networks 802.4 A token-passing bus 802.5 Token ring networks 802.6 Metropolitan area network (MAN) 802.7 Broadband Technical Advisory Group 802.8 Fiber-Optic Technical Advisory Group
802.9 Integrated voice and data networks 802.10 Standards for Interoperable LAN/MAN Security (SILS) (network security) 802.11 Wireless networks 802.12 100Mbps technologies, including 100BaseVGAnyLAN Each of these IEEE specifications outlines specific characteristics for LAN networking, including the speed, topology, cabling, and access method. Research and explore
Role of networks: Consider purpose, benefits, resource implications, communications, working practice, commercial opportunity, information sharing, collaboration. System types: Consider Peer-based, client-server, cloud, cluster, centralised, virtualised. Research and find out advantages and disadvantages to the different types Networking standards: Conceptual models e.g. OSI model, TCP/IP model; standards: e.g. IEEE 802.x. Topology: Logical e.g. Ethernet, Token Practical While completing this research: Find a suitable PC preferably with 2GB or better RAM Install Windows
Server from provided USBs Unit 2 Assignment 1 is officially launched today and available to read on Moodle. Protocols When computers were restricted to standalone systems, there was little need for mechanisms to communicate between them. However, it wasnt long before the need to connect computers for the purpose of sharing files and printers became a necessity. Establishing communication between network devices required more than a length of cabling; a method or a set of rules was needed to establish how systems would communicate. Protocols provide that method.
Protocols It would be nice if a single protocol facilitated communication between all devices, but this is not the case. You can use a number of protocols on a network. Each of which has its own features, advantages, and disadvantages. What protocol you choose can have a significant impact on the networks functioning and performance. Connection-Oriented Protocols Data delivery is guaranteed. The sending device re-sends any packet that the destination system does not receive.
Communication between the sending and receiving devices continues until the transmission has been verified. Because of this, connection-oriented protocols have a higher overhead and place greater demands on bandwidth. Connectionless protocols Offer only a best-effort delivery mechanism. The information is just sent; there is no confirmation that the data has been received. Error occurs? There is no mechanism to re-send the data, so transmissions made with connectionless protocols are not guaranteed.
Connectionless communication requires far less overhead than connection oriented communication. Popular in applications such as streaming audio and video, where a small number of dropped packets might not represent a significant problem. Internet Protocol (IP) Used to transport data from one node on a network to another. IP is connectionless, which means that it doesnt guarantee the delivery of data; it simply makes its best effort to do so. To ensure that transmissions sent via IP are completed, a higher-level protocol such as TCP is required. Another function of IP is addressing.
Defined in RFC 791 IP operates at the network layer of the OSI model. Transmission Control Protocol (TCP) Connection-oriented protocol Establishes a mutually acknowledged session between two hosts before communication takes place. TCP provides reliability to IP communications. Specifically, TCP adds features such as flow control, sequencing, and error detection and correction.
For this reason, higher-level applications that need guaranteed delivery use TCP rather than its lightweight and connectionless brother, UDP(User Datagram Protocol). Defined in RFC 793 TCP operates at the transport layer of the OSI model. IP Addressing To communicate on a network using TCP/IP, each system must be assigned a unique address. The address defines: The number of the network to which the device is attached Number of the node on that network.
Its a bit like a street name and house number in a persons home address. Each device on a logical network segment must have the same network address as all the other devices on the segment. All the devices on that network segment must then IP Addressing Continued Another set of numbers, called a subnet mask, defines which portion of the IP address refers to the network address and which refers to the node address. IP addressing is different in IPv4 and IPv6. IPv4 Decimal Binary 255.255.255.19 11111111.11111111.11111111.11000 2
000 Network Host Address address An IPv4 address is composed of four sets of 8 binary bits, which are called octets. The result is that IP addresses contain 32 bits. Each bit in each octet is assigned a decimal value. The leftmost bit has a value of 128, followed by 64, 32, 16, 8, 4, 2, and 1, left to right. Each bit in the octet can be either a 1 or a 0. If the value is 1, it is counted as its decimal value, and if it is 0, it is ignored. If all the bits are 0, the value of the octet is 0. If all the bits in the octet are 1, the value is 255, which is 128 + 64 + 32 + 16 + 8 + 4 + 2 + 1. By using the set of 8 bits and manipulating the 1s and 0s, you can obtain any value between 0 and 255 for each octet.
11111111 128 64 32 16 8 255 4 2 1 Identifying the Differences Between IPv4 Public and Private Networks IP addressing involves many considerations, not the least of which are public and private networks. A public network is a network to which anyone can connect. The best (and perhaps only pure) example of such a network is the Internet. A private network is any network to which access is restricted. A corporate network and a network in a school
are examples of private networks. A private network is any network to which access is restricted. Reserved IP addresses are 10.0.0.0, 172.16.0.0 to 172.31.0.0, and 192.168.0.0. The Internet Assigned Numbers Authority (IANA) is responsible for assigning IP addresses to public networks. However, because of the workload involved in maintaining the systems and processes to do this, IANA has delegated the assignment process to a number of regional authorities. For more information, visit http://www.iana.org/ipad dress/ip-addresses.htm . IPv4 Subnet Mask
Like an IP address, a subnet mask is most commonly expressed in 32-bit dotted- decimal format. Unlike an IP address, though, a subnet mask performs just one functionit defines which parts of the IP address refer to the network address and which refer to the node address. Each class of the IP address used for address assignment has a default subnet mask associated with it. Address Class Default Subnet Mask A 255.0.0.0 B 255.255.0.0 C
255.255.255.0 Subnet mask will be needed when setting up static IP addresses IPv4 Address Types Unicast Address Broadcast Address A single(Unique) address is specified. Data sent with unicast addressing is delivered to a specific node identified by the address. It is a point-to-point address link. At the opposite end of the spectrum from a unicast address. A broadcast address is an IP address that you can use to target all systems on a subnet or network instead of single hosts. In other words, a broadcast message goes to everyone on the network. Multicast A mechanism by which groups of network devices can send and
receive data between the members of the group at one time, instead of separately sending messages to each device in the group. The multicast grouping is established by configuring each device with the same multicast IP address. IPv6 When IPv4 was in development 30 years ago, it would have been impossible for its creators to imagine or predict the future demand for IP devices and therefore IP addresses. IPv4 has a total of 4,294,967,296 possible unique addresses that can be assigned to IP devices. The number of IP enabled devices increases daily at a staggering rate. Not all these addresses can be used by public networks. Many of these addresses are reserved and are unavailable for public use.
This reduces the number of addresses that can be allocated as public Internet addresses. Interesting fact: There was a IPv5. It was an experimental protocol that never went anywhere. IPv6 So IPv6 was created Started in the mid-1990s IPv6 uses a 128-bit(vs IPv4 32-bit) addressing scheme, enabling a huge number of possible addresses: 340,282,366,920,938,463,463,374,607,431,768,211,456 An IPv6 address is divided along 16-bit boundaries, and each 16-bit block is converted into a four-digit hexadecimal number and separated by colons. The
resulting representation is called colon-hexadecimal. IPv4 vs IPv6 Example IPv6 address How it works An IPv6 address is divided along 16-bit boundaries, and each 16-bit block is converted into a four-digit hexadecimal number and separated by colons. The resulting representation is called colon-hexadecimal. Now look at how it works: Hexadecimal IPv6 address: 2001:0000:4137:9e50:2811:34ff:3f57:febc Original binary: 0010 0000 0000 0001 Each 16-bit block is converted to Hexadecimal IPv6 Address Types 1/2 Unicast IPv6 Addresses
Specifies a single interface. Data packets sent to a unicast destination travel from the sending host to the destination. It is a direct line of communication. Global Unicast Addresses Global unicast addresses are the equivalent of IPv4 public addresses. These addresses are routable and travel throughout the network. Used in the Internet or any public domain. EUI 64: The last 64 bits of an IPv6 address are known as EUI-64 (Extended Unique Identifier, 64-bit) and are derived from the MAC address. There is a formula for converting a 48-bit MAC address into a 64-bit EUI-64 format, but you do not need to know this. IPv6 Address Types 2/2
Stateless Auto configuration Unique to IPv6, this allows for this configures automatic IP configuration. Link-Local Addresses Designated for use on a single local network. Link local addresses are automatically configured on all interfaces. On a single-link IPv6 network with no router, link-local addresses are used to communicate between devices on the link. Only used if Manuel IP, DHCP haven't configured an address. Link local addresses begin with FE80 e.g: FE80:0000:0000:0000
Comparing IPv4 and IPv6 Addressing For testing, packets are sent back to the same IP address Also called "local these reserved addresses are for local devices such as routers and PCs Automatic Private IP Addressing (APIPA) is a Windows feature Address Feature Loopback address Network-wide addresses IPv4 Address IPv6 Address 127.0.0.1
Private network addresses 10.0.0.0 172.16.0.0 192.168.0.0 IPv4 automatic private IP addressing 0:0:0:0:0:0:0:1 (::1) Global unicast IPv6 addresses Site-local address 172.16.0.0 ranges (FEC0::) Link-local addresses of the FE80:: prefix Autoconfigured addresses IPv4 public address ranges Other Noteworthy Protocols
DNS(Domain Name System) translates network address (such as IP addresses) into terms understood by humans (such as Domain Names) and vice-versa DHCP(Dynamic Host Configuration Protocol) can automatically assign Internet addresses to computers and users FTP(File Transfer Protocol) a protocol that is used to transfer and manipulate files on the Internet HTTP(HyperText Transfer Protocol) an Internet-based protocol for sending and receiving webpages POP3(Post Office protocol Version 3) a protocol used by e-mail clients to retrieve messages from remote servers SMTP(Simple Mail Transfer Protocol) a protocol for sending e-mail messages on the Internet
SSL(Secure Sockets Layer) is a protocol for transmitting private documents via the Internet. SSL uses a cryptographic system that uses two keys to encrypt data a public key known to everyone and a private or secret key known only to the recipient of the message. Research and explore Role of networks: Consider purpose, benefits, resource implications, communications, working practice, commercial opportunity, information sharing, collaboration. System types: Consider Peer-based, clientserver, cloud, cluster, centralised, virtualised. Topology: Logical e.g. Ethernet, Token Ring; physical e.g. star, ring, bus, mesh, tree, ring. Networking standards: Conceptual models e.g. OSI model, TCP/IP model; standards: e.g. IEEE 802.x.
Protocols: Purpose of protocols; routed protocols e.g. IPv4, IPv6, IPv6 addressing, Global unicast, Multicast, Link local, Unique local, EUI 64, Auto configuration, FTP, HTTP, Research and find out advantages and disadvantage s to the different types Unit 2 Assignment 1 is available to read on Moodle. This research covers half of the report.
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