ITM 301 IT Infrastructure - Slides & In-Person Notes - Fridays 2-5pm - Prisha Hathiwala.pdf

ITM 301 IT Infrastructure Important Links/Side Info Class Info Professor: Sec. 051 Dana Osborne Fridays, 2pm-5pm, Victoria Building 5th floor, 501 Office hou...

ITM 301 IT Infrastructure Important Links/Side Info Class Info Professor: Sec. 051 Dana Osborne Fridays, 2pm-5pm, Victoria Building 5th floor, 501 Office hours & email on D2L TA: name??? Office hours?? Email? Assignments (10%) Labs (10%) Weekly Weekly Group Projects (10%) Midterm (30%) Final (40%) Oct 25, 2024 D2L, IRL, VIC501, 2:10PM, 1 S1: Intro Objectives 1.1 Distinguish between the client-server & peer-to-peer models used to control access to a network 1.2 Identify types of applications & protocols used on a network 1.3 Describe various networking hardware devices & the most common physical topologies 1.4 Describe the seven layers of the OSI model 1.5 Explain best practices for safety when working with networks & computers 1.6 Describe the seven-step troubleshooting model for solving a networking problem 2 IN-CLASS NOTES Reviewed itm207 first 4 lectures about gates & 2^n All our laptops have an international address Ex. MAC address 48 bits How do we make it unique? ○ The first 24 bits are given to the vendors, 24 devices ○ The remaining 24 are used by the vendors Say you have 2 computers & you want to connect them without spending a lot of money Get a cable & connect them, connect their interfaces THIS IS AN EXAMPLE OF PEER-TO-PEER What if you needed to connect all laptops in class? Can’t do it the same way. Change topology All our laptops in this Victoria building classroom are connected to one (what’s it called?) TORRENT = (world’s largest) PEER-TO-PEER INSECURE; from someone’s computer, not a server Can get virus Client: A computer making a request from another Clients don’t share their resources directly with each other Access is controlled by entries in the centralized domain database Client computers access resources on another computer by way of the servers controlling the domain database USE ROUTER TO CONNECT MULTIPLE NETWORKS Ex. to connect home network with tmu network A switch won’t work on connecting 2 networks, only computers within the same network Use a router to connect the 2 networks Segment means 2 different networks, NOT the same network (it’s 1 separated into 2 different) Network hardware slide 8/9 about home router - We need an access point to connect wirelessly - Otherwise, physically connect (WIRED) - Always check your password is changed, otherwise can be hacked even offline USE FIBRE FOR INSIDE BOXES & COPPER WIRES TO CONNECT TO THE HOUSES COMPRESS & ENCRYPT EMAIL WHEN SENDING TO USE LESS BANDWIDTH 3  Network Models P2P Peer-to-Peer Model ❌ Client-Server Model ✅ Client-Server Model Application The OS of each computer on the network Resources are managed by the NOS A client computer requests data or a is responsible for controlling resource (network operating system) via a service from a 2nd computer, called the access. centralized directory database. server. No centralized control Windows domain 2 primary protocols: A logical group of computers TCP (Transmission Control Protocol) Computers, called nodes/hosts, form a that a Windows Server can IP (Internet Protocol) logical group of computers & users control Active Directory (AD) The centralized directory TCP/IP suite of protocols are used by May share resources database that contains user OSs for communication on a network May prevent access to resources account information & security for the entire group of List of several popular client-server ADVANTAGES computers. applications: Simple configuration A user can sign on to the Web service Less expensive/more network from any computer on Email services cost-effective compared to other the network & gain access to the FTP service network models resources that AD allows. Telnet service This process is managed by Remote applications DISADVANTAGES Active Directory Domain Remote Desktop Not scalable Services (ADDS) Not necessarily secure Can NOT direct-file download Not practical for large installations ADVANTAGES User credentials assigned from 1 place Multiple shared resource access centrally controlled Central problem monitoring, diagnostics, and correction capabilities More scalable 4  NOS RESPONSIBILITIES Manages client data, resources Ensures authorized user access Controls user file access Restricts user network access Dictates computer communication rules Supplies application to clients Server examples: Windows Server, Ubuntu Server, or Red Hat Enterprise Linux REQUIREMENTS More memory, processing, and storage capacity Equipped with special hardware ○ Provides network management functions Network Hardware Local Area Switch STAR Topology Network (LAN) Usually contained in a Receives incoming data from one of its ports & redirects it to All devices connect to one central small space, such as an another port or multiple ports device (usually a switch). office or building Will send the data to its intended destination. Can have several Switch belongs only to its local network. Backbone Router STAR-BUS Topology A central conduit that A device that manages traffic between two or more networks 3 switches daisy-chained together in connects the segments a SINGLE line are said to use a bus (pieces) of a network. A router is like a gateway between networks & belongs to two topology. or more local networks Might use higher However, each switch is connected transmission speeds & Can help find the best path for traffic to get from one network to computers via a star topology, different cabling than to another making it a star-bus topology, network cables connected to computers. Routers can be used in small home networks to connect the A topology that combines topologies home LAN to the Internet (a SOHO network—like a small is known as a hybrid topology. office-home office). Industrial-grade routers can have several network ports, one for each network it connects to. 5 6 MANs, WANs, PANs MANs & WANs often use different transmission methods & media than LANs. Metropolitan Area Wide Area Network Personal Area Network Network (MAN) (WAN) (PAN) Group of connected LANs in the A group of LANs that spread over a Smallest network. same geographical area. wide geographical area. A network of personal devices such Also known as a campus area Internet is the largest & most varied as your smartphone & your network (CAN). WAN. computer. 7 7-Layer OS Model OSI (Open Systems Interconnection) reference model - A 7-layer model developed to categorize the layers of communication The layers are numbered in order, starting with Layer 1, the Physical layer, at the bottom: Physical, Data Link, Network, Transport, Session, Presentation, and Application. Top to Bottom: APSTNDP 8  7. Application 6. Presentation 5. Session Describes the interface between 2 applications, on separate Responsible for Describes how data between applications is computers. reformatting, compressing, synced & recovered if messages don’t arrive &/or encrypting data in a intact at the receiving application. Application layer protocols are used by programs that fall into 2 way that the receiving categories: application can read. The Application, Presentation, and Session 1. Provide services to a user. Ex. a Browser & Web server An email message can layers are intertwined. Often difficult to 2. Utility programs that provide services to the system. be encrypted at the distinguish between them. 3. Ex. an SNMP monitors & gathers information about Presentation layer by network traffic the email client or by Most tasks are performed by the OS when an the OS. application makes an API call to the OS Payload—Data passed between applications (or utility programs) & the OS. Application programming interface (API) call is the method an application uses when it makes a request of the OS. 4. Transport 3. Network 2. Data Link Responsible for transporting Application layer payloads from 1 The entire Network layer The entire Data Link layer is called a frame application to another. message is called a packet. Layers 2 & 1: Responsible for interfacing 2 main Transport layer protocols: Responsible for moving with physical hardware on the local network. 1. TCP (Transmission Control Protocol)—Makes a messages from one node to connection with the end host, checks whether data was another until they reach the Protocols at these layers are programmed received; called a connection-oriented protocol destination host into the firmware of a computer's NIC & a. Need acknowledgement. other hardware. b. Once you say you have received the first packet, I’ll IP adds its own Network send the next packet. layer header to the segment The type of networking hardware/technology 2. UDP (User Datagram Protocol)—Does NOT guarantee or datagram. IP address: used on a network determines the Link Layer delivery by first connecting & checking if data is received; Assigned to each node on a protocol used. Ex. Ethernet & Wi-Fi called a connectionless protocol network. The network a. The sender doesn’t wait. layer uses it to uniquely The Link layer puts control information in a b. Sends the packets right away. identify each host. Link layer header & at the end of the packet c. Ex. livestream, telecast. in a trailer IP relies on several routing Protocols add their own control information in an area at the protocols to find the best MAC (Media Access Control) address: beginning of the payload (called a header). route for a packet to take to Hardware address of the source & destination reach the destination. Ex. NICs. Encapsulation—Process of adding a header to the data inherited ICMP & ARP. from the layer above Also called a physical address, hardware Network layer protocol address, or Data Link layer address The Transport layer header addresses the receiving application will divide large packets by a number called a port number. into smaller packets. A Embedded on every network adapter & are process called considered short-range addresses that can If a message is too large, TCP divides it into smaller messages fragmentation. only find nodes on the local network called segments. In UDP, the message is called a datagram. 1. Physical Simplest layer & is responsible for sending bits via a wired or Can be transmitted as: wireless transmission. Wavelengths in the air Voltage on a copper wire Light (via fibre-optic cables) 9 Protocol Data Unit (PDU) SUMMARY How Layers Work Together 10 S2: Networking Essentials Objectives 2.1 Identify & describe network & cabling equipment in commercial buildings & work areas 2.2 Create & analyze network diagrams 2.4 Track the progress of changes made to a network 11 Components of Structured Cabling TIA (Telecommunication Industry Association)/EIA (Electronic Industry Alliance)’s joint Commercial Building Wiring Standard: Also known as structured cabling, cabling standards. Based on hierarchical design & assumes a network is based on the star topology From the Demarc to a Workstation Data rooms, racks, other equipment: Entrance facility ○ Incoming network (such as the Internet) connects with the school or corporate network Demarc (demarcation point) ○ A device that marks where a telecommunications service provider’s network ends & the organization’s network begins MDF (main distribution frame/facility) ○ Centralized point of interconnection for an organization’s LAN or WAN (also called MC or main cross-connect) Data room ○ Enclosed space that holds network equipment (also called data closet, data center, equipment room, or telecommunications room) Racks ○ Holds various network equipment Patch panel ○ Panel of data receptors that can be mounted to a wall or a rack VoIP telephone equipment ○ Voice over IP is the use of any network to carry voice signals using TCP/IP protocols VoIP gateway VoIP P B X VoIP endpoints IDF (intermediate distribution frame) ○ Provides an intermediate connection between the M D F & end-user equipment on each floor & in each building Work area ○ Encompasses workstations, printers, other network devices Wall jacks ○ TIA/EIA standard calls for each wall jack to contain at least one voice & one data outlet 12 13  Cabling Patch Cables Cross-Over Cables Horizontal Cables Backbone (Vertical) Cables A relatively short length of cabling A relatively short length of Connects workstations to Consists of cables or with connectors at both ends. cabling with connectors at both the closest data room & wireless links that provide ends, switches housed in the interconnection between Used to set up communication room. the entrance facility & between 2 DIFFERENT types of Used to set up communication MDF & between MDF & device. between 2 SAME types of Mostly twisted pair cables IDFs. device. that are good for 100m Such as switching to PC (short connection, cheap). Use high-speed communication. A company can Such as pc to pc communication. high-voltage cable. give to customers. Not used for backbones (too expensive). 14 Network Diagrams Network diagrams ○ Graphical representations of a network’s devices & connections May show physical layout, logical topology, IP address reserves, names of major network devices, and types of transmission media Network mapping ○ The process of discovering & identifying the devices on a network. Cisco Systems set the standard for diagram symbols used to represent network devices Network diagrams provide broad snapshots of a network’s physical or logical topology Useful for planning where to insert a new switch or determining how a particular router, gateway, or firewall interact Wiring schematic ○ A graphical representation of a network’s wired infrastructure In detailed form, it shows every wire necessary to interconnect network devices Rack diagram ○ A drawing that shows devices stacked in a rack system 15 16 17  SUMMARY Organizations tend to follow a single cabling standard known as T IA/EIA-568 Commercial Building Wiring Standard or structured cabling A network begins at the demark & ends at a workstation Horizontal cabling connects workstations to the closest data room & to switches housed in that room ○ The backbone consists of the cables or wireless links that provide interconnection between the entrance facility & MDF & between the MDF & IDFs Data rooms are often serviced by HVAC systems that are separate from the rest of the building ○ Specialized products are available that monitor the critical factors of a data room’s environment Network diagrams may show physical layout, logical topology, IP address reserves, names of major network devices, and types of transmission media Review Questions 1. Which topology is 11. What is a cross-over cable? 21. What is a firewall? followed by the 12. What type of cabling we are going to use to 22. Why do we need a firewall? commercial building setup communication between 2 PCs? 23. Where do you want to place wiring standard? 13. What type of cabling we are going to use to the firewall? 2. What is a demarcation setup communication between 1 PC & one 24. What will happen if there is point? switch? no firewall? 3. What is horizontal 14. Difference between horizontal & backbone 25. Can we have more than one wiring? cabling. firewall in a computer 4. What is vertical wiring? 15. What is the maximum allowed distance network? 5. Why do we need MDF? from the data room to workstations? 26. How do we connect two 6. Where do we find IDF? 16. If the distance from data room to data jack switch in a computer 7. ISP is connected to is 80m, then what will be distance between network? MDF/IDF? workstation & data jack? 27. What is the use of wireless 8. Different VOIP 17. What type of cable is used for LANs? access point? equipments. 18. For local wired networks, which connector 28. How does VOIP work? 9. Which services are is used? 29. Which protocol carries voice provided by a standard 19. To divide a network which networking signal using TCP/IP TIA/EIA outlet? device we are going to use? protocols? 10. What is a patch cable? 20. What is the use of UPLINK port in a 30. Do we have any problem if switch? VOIP is used with TCP? 31. Which one will be faster: (TCP + VOIP) or (UDP + VOIP)? 32. Where does an organization's network start? 18 S2: In-Class Friday Sep 13, 2024 REVIEW LECTURE 1 If the backbone is slow, the whole network will be slow. If 1 device is disconnected from the switch, the network still works outside of that device. Not the case for star topology. Always need to keep a backup. Redundancy in a computer network is GOOD. PRO Like a backup tire we keep in case a tire fails. Improves availability in the network. If 1 switch is down, another switch is going to take over. Downtime is reduced. CON Cost Can sometimes have less funding for high-speed connection; i.e. slower than original 2^n = number of THINGS we can represent using “n” number of bits. Ex. 2^8 = 256 bits can be represented (2^n) - 1 = LARGEST BIT we can actually represent How many IP addresses can I generate using 32 bits? Answer: 2^32=4294967296 EXTRA: The largest bit we can represent is 2^32 - 1= 4294967295 19 In-Class Notes CISCO is a good investment because everywhere people are using CISCO networks. After all, it is not going to die. Prof always tries to invest in what he sees right in front of his eyes: windows, apple/mac, zoom, etc. Follow this diagram when you are working on diagram-based abs → 2 types of networks 1. Circuit switch a. Say you don't have any internet connectivity. b. Use a circuit switch to connect the computers. 2. Packet switch EXAMPLE Year is 2005 - Circuit switch network - Landline phone 1: North America - Landline phone 2:Asia - Used to set up a 2-way connection - Very good quality - The call initiator of the call pays for the whole setup process, ex. $1/minute Nowadays - Packet switch network - (VOICE OVER IP) VOIP NETWORK - The connection is so good - Now, we can connect a Toronto phone 1 with an Asia-based phone 2 by completing a calling card & using the calling card company’s server - Both are connected to the card company’s server - Use the internet to connect - It is getting clear, but there is always a chance of some packets being lost, so you get “Oh your connection is getting weaker, what did you say?” - Not paying anything extra for this connection other than the existing Internet subscription Make sure you’re identifying the MDFs & IDFs properly 20 BASED ON IMAGE BELOW, JUNIOR-LEVEL COMPUTER JOB INTERVIEW WILL ASK: Q. Where do we place our database? A. DNS server = PUBLICLY accessible EXTERNAL server. Check grades = go directly to the INTERNAL server. The purple box area is secure. Hackers need to go through 2 firewalls. 1st firewall is protecting public servers. 2nd firewall (near router) protects internal server. 21 S3: Network Infrastructure Network Addressing Sep 19, 2024 Objectives 3.1 Find the MAC address of a computer & explain its function in network communications 3.2 Configure TCP/IP settings on a computer, including IP address, subnet mask, default gateway, DNS servers 3.3 Explain the purpose of ports & sockets. Identify the ports of several common, network protocols 3.4 Describe domain names & the name resolution process 3.5 Describe the functions of core TCP/IP protocols TCP, IP, UDP, ARP etc. 3.6 Identify how each protocol’s information is formatted in a T CP/IP message 3.7 Explain different routing protocols 22 Addressing Overview Classful addressing: The dividing line between the network & host portions is determined by the numerical range the IP address falls in IPFv4 IEEE recommends the following IP addresses be used for private networks: ○ 10.0.0.0 through 10.255.255.255 ○ 172.16.0.0 through 172.31.255.255 ○ 192.168.0.0 through 192.168.255.255 Classes A, B, C Class D E 23 Data Link Layer MAC Network Layer IP Transport Layer Port Application Layer Address Address Numbers FQDNs MAC Address IPv4 addresses It is a 16-bit number. Fully qualified domain name (FQDN) - 48 bits - 32 bits - Written as 6 hex numbers - Written as 4 decimal numbers Port numbers A unique character-based name. separated by colons called octets - Ensure data is transmitted to the - Also called physical address - Each of the 4 octets can be any correct process among multiple Last part of an FQDN is called the number from 0 to 255 processes running on the top-level domain (TLD). First 24 bits are known as the OUI - Some IP addresses are reserved computer (Organizationally Unique Identifier) - Ex. 72.56.105.12 DNS is an Application layer or manufacturer-ID Socket client-server system of computers & - Assigned by the IEEE Class A, B, C - Consists of host's IP address & databases made up of these elements: - Available for internet use. the port number of an Namespace Last 24 bits make up the extension - Class A: starts with ‘0’ application running on the host: - The entire collection of identifier or device ID - Class B: starts with ‘10’ - Colon separates the two computer names & their - Manufacturers assign each - Class C: starts with ‘110’ values associated IP addresses N IC a unique device ID - Example-10.43.3.87:23 stored in databases on DNS Class D, E name servers around the - NOT available for general use. Port numbers are divided into 3 types: globe - Class D begins with octets Well-known ports-0 to 1023 Name servers 224–239. Used for Registered ports-1024 to - Hold databases, which are multicasting. 49151 organized in a hierarchical - Class E begins with octets Dynamic & private structure 240–254. Used for research. ports-49152 to 65535 Resolvers - A DNS client that requests Network Address Translation (NAT) information from DNS - Conserve public IP addresses name servers needed by a network Address translation 4 common DNS servers: - A gateway device substitutes Primary DNS server the private IP addresses with its - The authoritative name own public address. server for the organization Port Address Translation (PAT) - Holds the authoritative DNS - Assign a TCP port number to database for the each ongoing session between a organization’s zones local host & Internet host. Secondary DNS server - Backup authoritative name server for the organization IPv6 addresses Caching DNS server - 128 bits - Accesses the public DNS - Written as 8 blocks of data & caches the DNS hexadecimal number information it collects - 2001:0000:0B80:0000:0000:00 Forwarding DNS server D3:9C5A:00CC - Receives queries from local - Leading zeros in a 4-character clients but doesn’t work to hex block can be eliminated resolve the queries - If blocks contain all zeroes, they can be written as double DNS name servers are organized in a colons (::) hierarchical structure - Only 1 set of double colons is At the root level, root server used in an IP address hold information used to - 2001::B80:0000:0000:D3:9C5 locate top-level domain A:CC, or (TLD) servers 2001:0:B80::D3:9C5A:CC TLD servers hold (preferred, fewest zeroes) information about authoritative servers owned by various organizations 24 Unicast address - Specifies a single node on a network Broadcast address - Packets are delivered to all nodes on a network Multicast address - Packets are delivered to a selected nodes Anycast address - Can identify multiple destinations, with packets delivered to the closest destination Static IP addresses are assigned manually by the network administrator Dynamic IP addresses are automatically assigned by a DHCP (Dynamic Host Configuration Protocol) server A brief explanation of settings: Gateway - Device that nodes use for access to the outside world Subnet mask - Used to indicate what portion of an I P address is the network portion (network ID) & what part is the host portion (host ID) DNS server - Server responsible for tracking computer names & their IP addresses. Fun Fact: - Character-based names > numeric IP addresses - Domain names must be registered with an Internet naming authority that works on behalf of ICANN - ICANN restricts what type of hosts can be associated with.arpa,.mil,.int,.edu,.gov - Name resolution is the process of discovering the IP address of a host when you know the FQDN 25 Table 3-5 Some well-known top-level domains^ 26  TCP (Transmission Control Protocol) Step 1—Request for a connection (SYN) Step 2—Response to the request (SYN/ACK) Step 3—Connection established (ACK) After the three initial messages, the payload or data is sent. UDP (User Datagram Protocol) Unreliable, connectionless protocol Provides no error checking, sequencing, or flow control No three-way handshake is performed Makes UDP more efficient than TCP Does not guarantee delivery of data Useful for live audio or video transmissions over the Internet 27 IP (Internet Protocol) Operations Enables Drawbacks Network layer of the OSI TCP/IP to internetwork Unreliable, connectionless protocol model. Traverse more than Means that IP does not guarantee Specifies where data one LAN segment delivery of data & no session is should be delivered established before data is transmitted & more than one Identifies the data’s IP depends on TCP to ensure messages source & destination type of network are put back together in the right order IP addresses through a router & to ensure each message reaches the correct application on the receiving host ICMP (Internet Control Message Protocol) ICMP is a Network layer, core protocol that reports on the success or failure of data delivery. ICMP can indicate: When part of a network is congested When data fails to reach its destination When data has been discarded ICMP announces transmission failures to the sender, but does not correct errors it detects. ARP (Address Resolution Protocol) on I Pv4 Networks ARP works to discover the MAC address of a host or node on the local network ARP is a Layer 2 protocol Operates only within its local network ARP relies on broadcasting ARP table—The database of IP-to-MAC address mappings 28  Routers A router joins two or more networks & passes packets from one network to another Routers can do the following: Connect dissimilar networks (LANs & WANs) Interpret Layer 3 address Determine the best path for data to follow from point A to point B Reroute traffic if the path of first choice is down but another path is available Categories Tables Path Types Core routers, also called interior routers A database that maintains information Static routing Direct data between networks about where hosts are located & the most Network administrators configures a within the same autonomous system efficient way to reach them routing table to direct messages (AS) Routers rely on them to identify along specific paths. Edge routers, or border routers which router is the next hop to reach Example: A static route between a Connect an autonomous system a particular small business & its ISP with an outside network destination host Exterior routers Routing tables contain IP addresses Dynamic routing Refers to any router outside the & network masks that identify a Automatically calculates the best organization’s AS network that a host or another router path between two networks & Direct data between autonomous belongs to. maintains this information in a systems routing table Router can detect problems with failed or congested routes & reroute messages through a different path Metrics Protocols Properties of a route used by routers to Used by the routers to communicate with Table 4-10 Summary of common routing determine the best path to a destination: each other to determine the best path. protocols. Hop count Routers rate the reliability & priority of a Theoretical bandwidth & actual routing protocol’s data based on these throughput criteria: Delay, or latency, on a potential path Administrative distance Load, or the traffic or processing (AD)—A number indicating the burden protocol’s reliability. Example: MTU (maximum transmission unit) Convergence time—Time it or the largest IP packet size in bytes takes to recognize the best path allowable without fragmentation in the event of a change or Routing cost, or a value assigned to network outage a particular route Overhead—The burden placed Reliability of a potential path on the underlying network to Topology of a network support the protocol 29 3 Gateway Protocols Interior IGP (interior gateway protocols)—Used by core routers & edge routers within autonomous systems & are often grouped according to the algorithms they use to calculate the best paths: Distance-vector routing protocols ○ Calculate path on the basis of the distance to that destination Link-state routing protocols ○ Enables routers to communicate beyond neighboring routers in order to independently map the network & determine the best path OSPF (Open Shortest Path First): An IGP & a link-state protocol used on interior/border routers ○ Introduced as an improvement to RIP ○ Characteristics: Supports large networks Imposes no hop limits (unlike R IP) Uses a more complex algorithm for determining best paths Shared data Maintains a database of other routers’ links Low overhead, fast convergence Demands more memory & CPU power for calculations. Keeps network bandwidth to a minimum & provides a very fast convergence time. Stability Uses algorithms that prevent routing loops IS-IS (Intermediate System to Intermediate System): An IGP & link-state routing protocol ○ Uses the best-path algorithm similar to OSPF ○ Is designed for use on core routers only ○ Service providers generally prefer IS-IS because it’s more scalable than O SPF Exterior Used by edge routers & exterior routers to distribute data outside of autonomous systems. The only EGP currently in use is BGP. BGP (Border Gateway Protocol)—The only current EGP & is known as the “protocol of the Internet” Can span multiple autonomous systems The most complex of the routing protocols Hybrid EIGRP (Enhanced Interior Gateway Routing Protocol)—An advanced distance-vector protocol that combines some of the features of a link-state protocol Often referred to as a hybrid protocol Fast convergence time & low network overhead Easier to configure & less CPU-intensive than OSPF 30 S3: In-Class Friday Sep 20, 2024 Learned about command prompt & diagrams for the lab. 1 LAB ASSIGNMENT 4% [Please complete Part-A & Part-B. For both parts, explain your answers & submit screenshots as necessary. Submit one PDF file for both Part A & Part B] Prisha_Hathiwala_ITM301_Lab_1 31  S4: Cabling Sep 20, 2024 Objectives 5.1 Explain basic data transmission concepts, including throughput, bandwidth, multiplexing, and common transmission flaws. 5.2 Identify & describe the physical characteristics & official standards of coaxial cable, twisted-pair, and fibre-optic cable, as well as their related connectors. 5.3 Compare the benefits & limitations of various networking media. Throughput & Bandwidth Both are commonly expressed as bits transmitted per second, called bit rate Bandwidth: The amount of data that could be theoretically transmitted during a given period of time Throughput: Measure of how much data is actually transmitted during a given time period Transmission Flaws Noise Attentuation Latency Measured in dB (decibels). Loss of signal’s strength as it travels away Delay between signal from the source. transmission & receipt. Any undesirable influence degrading or distorting signal. Signals can be boosted: Round trip time (RTT): Repeater Time for packet to go Types of Noises: ○ Regenerates a digital signal to from sender to EMI (electromagnetic interference): its original form receiver, then back ○ Caused by motors, power lines, televisions, from receiver to copiers, fluorescent lights, etc. sender ○ 1 type of EMI is RFI (radio frequency interference) If packets experience Cross-talk: varying amounts of delay: ○ Signal on 1 wire infringes on adjacent wire They can arrive out of signal order ○ Alien cross-talk occurs between 2 cables A problem commonly called jitter or PDV (packet delay variation) 32  Duplexes Full Duplex Half-Duplex Simplex Signals travel in both directions Signals may travel in both directions Signals may travel in only 1 direction & is sometimes over a medium simultaneously. but only in 1 direction at a time. called one-way or unidirectional, communication. Multiplexing Definition Subchannels A form of transmission that allows multiple signals to travel Logical multiple smaller channels. simultaneously over 1 medium. Multiplexer (mux) Demuplexer (demux) Combines many channel signals. Separates the combined signals. Required at the transmitting end of the channel. Copper Line Multiplexes Tdm (Time Division Stdm (Statistical Time Fdm (Frequency Division Multiplexing) Division Multiplexing) Multiplexing) Divides channel into multiple time Transmitter assigns slots to nodes Assigns different frequency band for each intervals. according to priority & need. communications subchannel. Maximizes available bandwidth on a network. Fibre-Optics Multiplexes Wdm (Wavelength Dwdm (Dense Wavelength Cwdm (Coarse Wavelength Division Multiplexing) Division Multiplexing) Division Multiplexing) Carries multiple light signals Extraordinary capacity. Typically used on Channels are spaced more widely apart simultaneously by dividing a light high-bandwidth or long-distance WAN links. across entire frequency band. beam into different wavelengths or colors. 33  Copper Cables Coaxial cable: Hybrid fibre-coaxial System is used in our home for cable connection. Twisted-Pair Cable (TPC) Color-Coded Insulated Copper Wire Pairs In Ethernet Networks 0.4–0.8 mm diameter. Contains 4 wire pairs: Encased in a plastic sheath. Fast Ethernet (100Mbps) uses 1 pair to send data & 1 pair to Every two wires are twisted together. receive data Networks using Gigabit Ethernet use all 4 pairs for both sending & receiving Most common twisted pair types: Category (cat) 3, 5, 5e, 6, 6a, and 7 CAT 5e or higher used in modern LANs 2 categories: Shielded twisted pair (STP) Unshielded twisted pair (UTP). Ethernet TPC (STP) Shielded Twisted Pair (UTP) Unshielded Twisted Pair Individually insulated One or more insulated wire pairs encased in plastic sheath: Surrounded by metallic substance shielding (foil): No additional shielding Barrier to external electromagnetic forces Less expensive, less noise resistance Contains electrical energy of signals inside Must be grounded 34  Comparing STP & UTP Throughput Cost STP & UTP can transmit the same rates. STP & UTP vary in cost. STP is more expensive than UTP. Connector Noise Immunity STP & UTP use Registered Jack 45 (RJ_45). STP is more noise resistant. Size & Scalability Maximum segment length for both: 100 meters on Ethernet networks that support data rates from 1 Mbps &10 Gbps. Ethernet Standards for Twisted Pair Cables A cable’s category (Cat 5e or Cat 6) determines the fastest network speed it can support. A device’s NIC is also rated for maximum network speeds. Most LANs today use devices & NICs that can support Fast Ethernet & Gigabit Ethernet Devices can auto-negotiate for the fastest standard they have in common 35  Fibre-Optic Cable Definition, Cladding, Benefits, Drawbacks Throughput, Cost, Noise Immunity, Transmission Size & Scalability Contains one or more glass or plastic Benefits over copper cabling: Proven reliable in transmitting data at rates that can fibres at its center (core) Extremely high throughput. reach 100 gigabits per second per channel. Very high noise resistance. Data transmission: Excellent security. Most expensive transmission medium. Pulsing light sent from laser or ○ Very hard to hack light-emitting diode (LED) ○ Where to get the Unaffected by EMI through central fibres devices to read & Cladding: understand it? Very Segment lengths vary from 2 to 40,000 meters. Layer of glass or plastic expensive devices. Depends on the light’s wavelength & type of cable. surrounding fibres Able to carry signals for Different density from glass or longer distances. plastic in strands Reflects light back to core Drawbacks: Allows fibre to bend More expensive than twisted pair cable. Requires special equipment to splice. Mode Fibres (SMF) Single Mode Fibre (MMF) Multimode Fibre Consists of narrow core (8–10 microns in diameter): Contains a core with a larger diameter than single mode fibre Laser-generated light travels over one path Common sizes: 50 or 62.5 microns ○ Little reflection Light does not disperse as signal travels Laser or LED generated light pulses travel at different angles Greater attenuation than single-mode fibre Can carry signals many miles: Before repeating is required Common uses: Cables connecting routers, switches, and servers on the Rarely used for shorter connections: backbone of a network Due to cost The Internet backbone depends on SMF 36  Fibre Connectors MMF Connectors SMF Connectors Classified by th number of fibres. Classified by size & shape of the ferrule. Ferrule Examples The extended tip of a connector that makes contact with the ST, SC, FC, MT-RJ, and LC are examples of connectors. receptacle in the jack. Media Converter Hardware that enables networks or segments running on different media to interconnect & exchange signals Completes the physical connection & converts electrical signals from copper cable to light wave signals - Can also be used to convert networks using MMF/SMF Ethernet Standards for Fibre-Optic Cables Common Fibre Cable Problems Fibre Type Mismatch Wavelength Mismatch Dirty Connectors More of a fibre core mismatch. Even same-mode cables SMF, MMF, and POF (Plastic Optical Signal loss & other errors can be mismatched if the cores have different widths. fibre) use different wavelengths. can start to cause problems. 37 Review Questions 38 S4: In-Class Friday Sep 27, 2024 Lab answers 1. P2P 2. NICs, USB cable, Patch cables, RJ Connectors 3. Up to us 4. Printer sharing hub connected to a computer 5. Diagram a. In-class diagram (Was it the same as what Matthew sent me??) b. Use computer symbol in future (it’s okay this first time if you didn’t) c. Didn't need a router We’ll need the “arp -a” command prompt for the next lab Client sends syn request & random sequence number Server returns syn,(?) & sequence number + 1 Client +1 to the server sequence number Review routers - Always fund fastest way - Some took 11 hops, another took 8 hops because fast router at home - Cannout use the same type of router everywhere, different ones worldwide - Different algorithms. 2 types: - ? - ? - Switch has memory: maintains a table of mac addresses per port - Router also maintains a routing table of how to reach - Only need to know name of destination - (Dynamic) Default point - When I don’t know how to reach destination, pass object (packet) to next person (router) & again & again till it reaches destination, remembering who has it when till it reaches destination (remember who & how many people we gave the object to until it reaches the person across the room) - Shortest hop counts algorithms are like Google Maps - Checks distance, congestion, etc. to find fasting route - Path cost - Administrative Distance = number of cost - Lower the better = more reliable path 39  - Convergence time - Turned off router - Turned them on - Needs time to learn all the nodes in the network - Can change the network outage - Right away tries to recalculate new path - Overhead - 7 layers - Each layer adds some new information - This additional information is calculated as overhead in the network - Distance Vector Issue - Problem: every 30 seconds, it broadcasts routing table - Regardless of whether or not it changed - Unnecessary - RIP - Can contain only 15 hops - Inexpensive - Good for smaller networks, not big company Went over lecture slides & in-person examples 40  S5: Wireless Networking Oct 4, 2024 Wireless Networking - chapter 6 - Studocu Objectives 6.1 Identify & describe various types of wireless networking characteristics 6.2 Explain the various wireless standards that support the Internet of Things 6.3 Explain 802.11 standards & innovations 6.4 Secure a Wi-Fi network Wireless Transmissions Characteristics Wireless networks (WLANs) Networks that transmit signals through the air via RF (radio frequency) waves Wired & wireless signals share many similarities ○ Use of the same Layer 3 & higher protocols The nature of the atmosphere makes wireless transmission different from wired transmission Wireless Spectrum Is the frequency range of electromagnetic waves used for data/voice communication Spans frequency ranges or bands between 9 kHz & 300 GHz Some bands have only a single frequency (called a fixed frequency) for that band Antennas Wireless signals originate from electrical current traveling along a conductor: Travels from the transmitter from an antenna The antenna emits the signal as a series of electromagnetic waves into the atmosphere At the destination, another antenna accepts the signal & a receiver converts it back to the current. Unidirectional (directional antenna) ○ Wireless signals along single-direction ○ Dish antenna, helical antenna etc. Omnidirectional antenna: ○ Receives wireless signals with equal strength & clarity in all directions ○ Wireless routers 41 Signal Propagation How a wave travels from 1 point to another LOS (line of sight) ○ The signal travels in a straight line directly from the transmitter to the receiver When obstacles are in a signal’s way, the signal may: ○ Pass through them ○ Be absorbed into them Fading: ○ As the signal runs into obstacles, its energy will gradually fade Attenuation: ○ Signal weakens Moving away from the transmission antenna ○ Correcting signal attenuation Increase the power of the transmission Repeat the signal from a closer broadcast point called a wireless range extender Interference: ○ Wireless signals are more vulnerable to noise No wireless conduit, shielding Refraction: ○ As a wave travels through objects the wave’s direction, speed, and wavelength are altered (or refracted) Reflection: ○ The signal bounces back toward its source Scattering: ○ Diffusion in multiple different directions Diffraction: ○ Signal splits into secondary waves Wireless Standards for the IoT (Internet of Things) IoT: Made up of any device that can be connected to the Internet Personal monitoring devices: One of the fastest-growing areas of IoT Smart home devices: Interlink devices such as locks & lights, security cameras, etc. HAN (home area network) ○ Connected devices within a home create a type of LAN WPAN (wireless personal area network) ○ Include short-range wireless technologies such as Bluetooth & ZigBee PANs ○ Rarely exceed about 10 meters 42 Z’s ZigBee (Wireless) Z-Wave Low-powered, Battery-conserving A smart home protocol Designed to handle small amounts of data A Z-Wave network controller (called a hub) Ideal for use in ISM (industrial, scientific, and medical) sensors Receives commands from a smartphone or computer It uses 2.4 GHz systems & relays the commands to various smart devices on Used in IoT devices for: its network ○ Building automation, HVAC control, AMR (Automatic Have a range of up to 100 m per hop & uses 915 MHz Meter Reading), and fleet management frequency band Bluetooth Requires close proximity to form a connection - Exact distance requirements depend on the class of Bluetooth device Before 2 Bluetooth devices can connect, they must be paired Bluetooth interfaces are susceptible to a range of security risks ○ Bluejacking: A connection is used to send unsolicited data ○ Bluesnarfing: A connection is used to download data without permission Operates in the radio band of 2–2 GHz & hops between frequencies within that band to help reduce interference RFID (Radio Frequency Identification): Uses electromagnetic fields to store data on a small chip (RFID tag) ○ Includes an antenna that can transmit & receive Passive & Active RFID RFID is commonly used for inventory management An RFID tag might also be embedded in a credit card, allowing for so-called “contactless” payment NFC (Near-Field Communication): A form of RFID that transfers data wirelessly over very short distances Signal can be transmitted one way by an NFC tag, or smart tag ○ When employees need access to a secure area The NFC tag collects power from the smartphone or other device by magnetic induction Wireless USB Based on the UWB (Ultra-Wideband) radio platform Certified W-USB products mimic wired USB 2.0 connections ○ Similar speeds, security, ease of use, and compatibility UWB radios transmit in the range between 3.1 and 10.6 GHz 43 IR (Infrared) IR is used primarily to collect data through various sensors ○ Exists just below the spectrum visible to the human eye IR sensors are used to collect information such as: ○ Presence or level of liquid ○ Commands from a control device 802.11 WLAN Standards The most popular standards used by WLANs is Wi-Fi Developed by IEEE’s 802.11 committee 44 Access Methods Wireless Devices CSMA/CA RTS/CTS CANNOT prevent collisions Carrier Sense Multiple Access with Request to Send/Clear to Send) protocol Use different access method Collision Avoidance Avoids hidden node problem Minimizes collision potential Uses ACK packets to verify every transmission 45 Association Packets exchanged between computer & access point to gain Internet access Scanning SSID BSS Active scanning transmits a special SSID (Service set identifier) BSS (Basic service set) frame Unique character string identifying Group of stations sharing an access ○ Known as a probe access point point Passive scanning listens for special ○ Beacon Frame Information signal Configured in access point BSSID (Basic service set identifier) ○ Known as a beacon frame Better security, easier network Group of stations identifier transmitted by the access point management ESS BSSs within Single ESS ESS (extended service set): As devices are moved between BSSs within a single ESS: Group of access points connected to the same LAN Connecting to a different AP requires reassociation ○ Share ESSID (extended service set identifier) Occurs by simply moving Allows roaming High error rate ○ Station moving from 1 BSS to another without losing connectivity 46 Wireless Topologies Ad Hoc Infrastructure Mesh A small number of nodes closely positioned An AP (access point) accepts wireless signals from Several access points transmit directly to each other. multiple nodes and retransmits them to the rest of the work as peer devices network. on the same network. WiFi Network Security 802.11 Standard Security Authentication None by default Process of comparing and matching a client’s credentials SSID: only item required with the credentials in a database MAC Filtering Encryption Prevents the AP from authenticating any device whose Use of an algorithm to scramble data MAC address is not listed. 47 WPA/WPA2 (Wi-Fi Protected Access) WPA WPA2 Additional Security Options Dynamically assigns every Replacement for WPA Create a separate guest network transmission its own key A stronger encryption protocol through a Wi-Fi router/access point Set up a captive portal ○ The first page a new client sees in the browser when connecting to a guest network ○ Requires user to agree to a set of terms and conditions before gaining further access Security Threats to WiFi Networks War Driving War Chalking Evil Twin A hacker searches for unprotected wireless Hackers draw symbols with chalk on A rogue AP planted in a networks by driving around with a laptop the sidewalk or wall near a vulnerable network’s geological area configured to receive & capture wireless AP to make it known to other hackers to pose as an authorized AP data transmissions WPA Attack BSSs within Single ESS Involves an interception of the network key Cracking a PIN to access an A Ps settings communicated between stations and APs Cracked through a brute force attack It is also called WPA cracking WiFi Network Tools Spectrum Analyzer Wireless analyzer (Wi-Fi analyzer) Can assess the quality of the wireless signal Can evaluate Wi-Fi network availability, optimize Wi-Fi signal settings, and help identify Wi-Fi security threats 48  S5: In-Class Friday Oct 4, 2024 Went over slides & real-world examples. Ended at 3:16 pm. Worked on Lab. NOTE: QUIZ DUE OCTOBER 10TH 2024 AT 11:59 PM!!!!!!!!!!!!!!!!!!!!! Lab 3 Quiz 49 50 51  S6: Network Architecture Oct 11, 2024 Objectives: 1. Describe and explain virtualization technologies, including how virtual machines connect with a network and how networking infrastructure devices can be virtualized 2. Describe cloud computing categories and models, and discuss concerns regarding cloud connectivity and security 3. Secure network connections using encryption protocols 4. Configure remote access connections between devices Virtualization Virtualization Definition Host A virtual, or logical, version of something rather than the Physical computer “hosting” a virtual machine actual, or physical, version Guest Hypervisor Each virtual machine Creates & manages a VM Manages resource allocation & sharing between a host and any of its guest VMs Type 1 Hypervisor Type 2 Hypervisor It installs on a computer before any OS & is called a It installs in a host OS as an application & is called a bare-metal hypervisor hosted hypervisor Customize the VMs Elements of Virtualization A guest OS Amount of memory Hard disk size Processor type and other options Advantages: Efficient use of resources, Cost and energy savings, Fault and threat isolation, Simple backups, recovery, and replication Disadvantages: Compromised performance, Increased complexity, Increased licensing costs. Single point of failure 52 Network Connection Types 1 VM = 1 vNIC (virtual NIC): VM’s vNIC is selected: Every VM has its own vNIC (virtual NIC): Hypervisor creates a connection between that VM & the Can connect the VM to other machines host Operates at the Data Link layer Connection might be called a bridge or switch (vSwitch) 1 VM = Several vNICs 1 Host = Multiple vSwitches Each VM can have several vNICs Controlled by the hypervisor The maximum number depends on the limits imposed by the hypervisor Host-Only Mode VMs on one host can exchange data with each other and the host Cannot communicate with nodes beyond the host Never receive or transmit data with the host’s physical NIC Images 53 Cloud Computing Flexible provision of data storage, applications, and services to multiple clients over a network. Features vDesktops, Server Info On-demand service Can provide virtual desktops Support for multiple platforms ○ Operating environments hosted virtually Resource pooling and consolidation Developers can load any kind of software on the servers Metered service and test it from afar Elastic services and storage ○ Cloud services providers can make sure the ○ Storage capacity can quickly or automatically be development servers are secure, regularly backed up scaled up or down Most cloud service providers use virtualization software to supply multiple platforms to multiple users Characteristics 4 Categories Cloud computing service models are categorized by the types of services provided: Traditional ○ All hardware, software, and everything else is located and managed at the organization’s location IaaS (Infrastructure as a Service) ○ Hardware services and network infrastructure devices are provided virtually ○ Including end user interfaces such as H VDs (hosted virtual desktops) PaaS (Platform as a Service) ○ OS, runtime libraries or modules the OS provides to applications, and the hardware on which the OS runs SaaS (Software as a Service) ○ Applications XaaS (Anything as a Service or Everything as a Service): ○ A broader model ○ Cloud can provide any combination of functions 54  Cloud Computing Service Models Deployment Models Cloud services are delivered in a variety of deployment models Public Cloud Private Cloud Service provided over public transmission lines Service established on an organization’s own servers in its own data center Community Cloud Hybrid Cloud Service shared between multiple organizations Combination of the other service models into a single deployment 55 (Key) Encryption Protocols Use mathematical code, called a cipher, to scramble data into a format that can only be read by reversing the cipher. Used to keep information private Primarily evaluated by three benchmarks (CIA Triad = principles of standard security model): ○ Confidentiality ○ Integrity ○ Availability Key: Random string of characters Woven into original data’s bits Generates unique data block called ciphertext Created according to a specific set of rules (algorithms) Key encryption can be separated into two categories: Private key encryption Public key encryption Key pair = Combination of public & private keys Asymmetric encryption = Requires two different keys Digital certificate = Holds identification information & the user’s public key CA (certificate authority) = Issues, maintains digital certificates PKI (Public key Infrastructure) = Use of certificate authorities to associate public keys with certain users Private Key Encryption Public Key Encryption Data is encrypted using a single key Data encrypted using two keys ○ Known only by the sender & receiver ○ Private key: The user knows Symmetric encryption ○ Public key: Anyone may request ○ Same key used during both encryption & decryption Public key server: ○ Publicly accessible host ○ Freely provides users’ public keys 56 IPsec (Internet Protocol Security) Encryption protocol suite that defines rules for encryption, authentication, and key management for TCP/IP transmissions 5-Step IPsec Secure Connection: IPsec initiation Key management Security negotiations Data transfer Termination SSL & TLS (Secure Sockets Layer) & (Transport Layer Security) Both are methods of encrypting TCP/IP transmissions, including Web pages & data entered into Web forms. Both protocols work side by side & are widely known as SSL/TLS or TLS/SSL When a client & server establish a SSL/TLS connection, they establish a unique session Association between client & server ○ Defined by agreement ○ Specific set of encryption techniques Created by SSL handshake protocol Handshake protocol ○ Allows client & server to authenticate ○ Similar to a TCP three-way handshake 57 Remote Access Service that allows a client to connect with & log on to a server, LAN, or WAN in a different geographical location. Requires a type of RAS (remote access server). 2 types of RAS: Dedicated devices Software running on a server Types of remote access: Point-to-point over a dedicated line ○ A Data Link layer protocol; Directly connects 2 WAN endpoints ○ Negotiate and establish a connection between two computers ○ Use an authentication protocol to authenticate a client to a remote system Terminal emulation ○ Also called remote virtual computing ○ Allows a user on 1 computer to control another computer across a network connection ○ Examples of command-line software: Telnet ➔ A terminal emulation utility that allows an administrator or other user to control a computer remotely ➔ Provides little security for establishing a connection (poor authentication) ➔ Provides no security for transmitting data (no encryption) SSH (secure shell) ➔ A collection of protocols that provides for secure authentication & encryption ➔ Guards against a number of security threats: ◆ Unauthorized access to a host ◆ IP spoofing ◆ Interception of data in transit ◆ DNS spoofing ➔ Developed by SSH Communications Security: Version requires a license fee ➔ Open source versions available: Open SSH ➔ Secure connection requires SSH running on both client & server ➔ Allows for password authentication using public and private key generation ➔ Configuration options: ◆ Use 1 of several encryption types ◆ Require client password ◆ Perform port forwarding: Redirect traffic that would normally use an insecure port to a S SH-secured port ○ Examples of GUI-based software: Remote Desktop for Windows join.me VNC Team Viewer Virtual private network (VPN) 58 VPNs (Virtual Private Networks) A VPN is a network connection encrypted from end to end that creates a private connection to a remote network, sometimes referred to as a tunnel. VPNs can be classified according to 3 models: Site-to-site VPN Client-to-site VPN ○ Also called host-to-site VPN or remote-access VPN Host-to-host VPN A router-based VPN is the most common implementation on UNIX-based networks Server-based VPNs are most often found on Windows networks VPN concentrator: Authenticates VPN clients Establishes tunnels for VPN connections Manages encryption for VPN transmissions 2 primary encryption techniques used by VPNs: IPsec SSL 59 VPN Tunneling Protocols To ensure VPNs can carry all types of data securely. Special VPN protocols encapsulate higher-layer protocols in a process known as tunnelling. Many VPN tunneling protocols operate at the Data Link layer ○ Encapsulate the VPN frame into a Network layer packet Some VPN tunneling protocols work at Layer 3 ○ Enables additional features and options PPTP (Point-to-Point Tunneling Protocol) L2TP (Layer 2 Tunneling Protocol) GRE (Generic Routing Encapsulation) Open VPN IKEv2 60 S6: In-Class Friday Oct 11, 2024 There is no lab this week Will introduce the group projects soon 61