Presentation on theme: "Networking Fundamentals Networking 101. What is a network? A network can be 2 or more devices connected together to share hardware or software, usually."— Presentation transcript:
Networking Fundamentals Networking 101
What is a network? A network can be 2 or more devices connected together to share hardware or software, usually sharing the same media/topology, protocol and a client software or service
Local Area Networks A local area network (LAN) is a collection of computers located in a relatively small area and connected by a common medium. The pattern in which computers in a LAN are connected is called the topology. LAN topologies include bus, star, and ring.
Wide Area Networks
Half-Duplex and Full-Duplex Communications
Topologies In this section we will look at the different topologies used today Recognizing Different Topologies -Star--Bus--Mesh--Ring-
Star Topology A star topology is a group of computers connected at a central location such as a hub or switch. The failure of one PC will not effect the network.
Bus Topology In this configuration all PC’s are connected (daisy chained) by one coaxial cable using terminators and T connectors. If one node fails then everything before that node falls off the network.
Mesh Topology In this configuration all PC’s are connected to everything on the network simultaneously (Redundancy).
Ring Topology A ring topology looks like a star topology but the technology used is different. Token passing is used allowing only one message at a time to be sent to avoid collisions.
Networking Technologies IEEE (Institute of Electrical and Electronics Engineers) In February of 1980, this institute developed a set of standards called the 802 project. This project was built to standardized networking technologies for past present and future.
Networking Technologies Ethernet (802.3) The internet operates using Ethernet technology. It was developed by Xerox and has been defined as by IEEE. Ethernet is used in the Star and Bus topologies.
Networking Technologies Wireless (802.11) There are 2 commonly used wireless standards b – 11Mbps g – 54Mbps Both technologies use a 2.4GHz radio wave band and are used in the Star topology.
Coaxial Cable Types RG-8RG-58 ApplicationThick EthernetThin Ethernet Thickness0.405 inch0.195 inch Connector Type NBNC with a T-fitting
Cable Category’s The category of a twisted-pair cable indicates the tightness of the twist applied to each pair of wires with-in a cable. The twist help prevent EMI and crosstalk. The tighter the twist the faster the speed.
UTP Cable Grades EIA/TIA GradeApplications Category 3Voice-grade telephone networks, 10-Mbps Ethernet, 4- Mbps Token Ring, 100Base-T4 Fast Ethernet, and 100Base-VG-AnyLAN Category 416-Mbps Token Ring Category 5100Base-TX Fast Ethernet, Synchronous Optical Network (SONET), and Optical Carrier (OC3) Asynchronous Transfer Mode (ATM) Category 5e or higher1000Base-T (Gigabit Ethernet)
Media Connectors RJ-11 = Standard phone jack connector consisting of 2 pairs of wires. RJ-45 = Common Ethernet cable connector. Used to connect network devices together for communications and contain 4 pairs of wires.
Cable Standards Patch Cable A patch cable is a straight through cable that relies on a switch or hub to cross the send and receive wires. Crossover Cable A crossover cable is used for a direct connection when no hub or switch is used. It looks identical to a Patch cable except that pins (1 and 3) and (2 and 6) are crossed (Send and Receive wires).
Network Components Hubs A hub is a device that has multiple ports which many connections can be made. Hubs bear no real intelligence and are generally used to simply connect segments of networks together.
Network Components Switches A Switch looks similar to a hub but has intelligence. A switch controls traffic by learning its environment and more effectively transmitting data to decrease network traffic.
Network Components Router A router is a device that forwards traffic from one network to another, this makes the internet possible. When a router receives a message it determines if it belongs to its network and either receives or sends it on. It is also known as a Gateway meaning that it can translate data from one format to another.
Network Components Firewall A firewall is a software or hardware system that separates a computer or network from one another. Firewalls are used to filter data coming in and out of PC’s and networks acting much like an administrator.
What Is a Virus? A virus is a software routine that is deliberately designed to attach itself to another piece of software on a computer, perform some preprogrammed activity, and spread to other computers on the network. The worst types of viruses are engineered to irretrievably destroy all or part of the data stored on the computer by wiping out hard drives. Potentially damaging programs such as viruses, Trojan horses, and worms can find their way onto a network through file downloads, s, or even removable disks. Like biological viruses, computer viruses are designed to replicate themselves by infecting other pieces of software. A virus on an infected removable disk can migrate to the computer’s hard drive and infect the code on the hard drive.
Network Components Mac Address A MAC address (Media Access Control) also referred to as a physical address is burned into each NIC card much like a serial number and no 2 cards are alike. The first 3 sets of numbers identify the manufacturer while the last 3 sets identify the ID number i.e B-00-4B-F6
Network Protocols Two of the basic protocols used today are: TCP/IP and NetBui
NetBEUI Characteristics Original Microsoft Windows default networking protocol Designed for small local area networks (LANs) Does not support Internet communications Does not need configuration
TCP Characteristics TCP is the acronym for Transmission Control Protocol. TCP is Connection oriented Reliable It is used to carry large amounts of data. It provides services that Internet Protocol (IP) lacks.
TCP/IP History Developed in the 1970s Created for use on the ARPANET Used by UNIX Predates the PC, the Open Systems Interconnection (OSI) model, and Ethernet Platform and operating system independent
IP Address Identifies the computer to the network Required for TCP/IP communication Must be unique on the network Must not be chosen at random Must be assigned by a network administrator
The Four TCP/IP Layers Link. Includes Serial Line Internet Protocol (SLIP) and Point-to-Point Protocol (PPP) Internet. Includes Internet Protocol (IP), Internet Control Message Protocol (ICMP), and Internet Group Membership Protocol (IGMP), plus some dynamic routing protocols Transport. Includes Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) Application. Includes Hypertext Transfer Protocol (HTTP) and File Transfer Protocol (FTP)
The OSI Model and the TCP/IP Model
Basic TCP/IP Client Configuration Parameters IP address Subnet mask Default gateway Domain Name System (DNS) server address
Other TCP/IP Parameters ParameterFunction Subnet maskIndicates which Internet Protocol (IP) address bits identify the network and which identify the host Required for TCP/IP communication Default gatewayIdentifies the router that the computer should use to access other networks DNS server addresses Identifies the DNS servers that the client will use to resolve host and domain names into IP addresses
The Local Area Connection Properties Dialog Box
IP Address Characteristics 32-bit value that contains a network identifier and a host identifier Expressed in dotted decimal notation Assigned to network interface adapters, not computers
IP Address Assignments Every network interface adapter on a network must have The same network identifier as the others on the network A unique host identifier The Internet Assigned Numbers Authority (IANA) assigns network identifiers, but you typically obtain network addresses from an Internet service provider (ISP). Network administrators assign host identifiers.
IP Address Classes
IP Address Class First Bit/Byte Values ClassFirst BitsFirst Byte Values A01–127 B10128–191 C110192–223
IP Addressing Rules All the bits in the network identifier cannot be set to zeros. All the bits in the network identifier cannot be set to ones. All the bits in the host identifier cannot be set to zeros. All the bits in the host identifier cannot be set to ones.
What Is a Subnet Mask? A subnet mask is a 32-bit binary number that indicates which bits of an IP address identify the network and which bits identify the host. The 1 bits are the network identifier bits and the 0 bits are the host identifier bits. A subnet mask is typically expressed in dotted decimal notation.
Subnet Masks for IP Address Classes ClassSubnet Mask A B C
Private Network Addresses ClassNetwork Addresses A through B through C through
IPv6 Addressing Expands IP address space from 32 to 128 bits Designed to prevent the depletion of IP addresses Uses XX:XX:XX:XX:XX:XX:XX:XX notation
Telnet Telnet provides remote control capabilities. Telnet clients can execute commands on a server and view the results. Telnet was designed for UNIX systems. All Windows versions include a Telnet client.
FTP You can use the File Transfer Protocol (FTP) to transfer files between computers, create and remove directories, rename and delete files, and manage access permissions. All Windows computers have a command-line FTP client. Windows 2000 and Windows NT servers have an FTP server built into Microsoft Internet Information Services (IIS).
UDP Characteristics UDP is the acronym for User Datagram Protocol. UDP is defined in RFC 768. It is a connectionless protocol. It is used primarily for brief request/reply transactions.
DHCP Dynamically allocates IP addresses from a pool Reclaims unused addresses Prevents IP address duplication Supplies all TCP/IP parameters
The HOSTS File A HOSTS file is a lookup table containing a list of host names and their equivalent IP addresses. Each computer has its own HOSTS file. As the Internet grew, the HOSTS file became impractical, and the Domain Name System (DNS) eventually replaced it.
DNS Characteristics DNS defines A hierarchical namespace for computer networks A service for resolving names into IP addresses
The DNS Namespace
The DNS Name Resolution Process
Ping Characteristics Supplied with virtually every TCP/IP implementation Tests connectivity to another TCP/IP system Syntax: ping target
Ping Output (Typical) Pinging cz1 [ ] with 32 bytes of data: Reply from : bytes=32 time<10ms TTL=128 Ping statistics for : Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 0ms, Average = 0ms
Types of Remote Network Connections Computer to Internet service provider (ISP) Computer to private network Computer to computer Network to network
Public Switched Telephone Network (PSTN) Technical name for the standard voice telephone system Also known as the Plain Old Telephone Service (POTS) Works with asynchronous modems to transmit data between computers at almost any location Typically uses copper-based, twisted-pair cable with RJ-11 jacks
Modems A modem (modulator/demodulator) is required to convert a computer’s digital signals to the analog signals used by the PSTN. At the other end of the connection, another modem converts the analog signals back to digital.
Virtual Private Network (VPN) Communications The remote user connects to the Internet by using a modem to dial in to a local ISP. The network is permanently connected to the Internet and has a server that is configured to receive incoming VPN connections. The remote computer and the network server establish a secured connection across the Internet. This technique is called tunneling, because the connection runs across the Internet inside a secure conduit.
Integrated Services Digital Network Integrated Services Digital Network (ISDN) is a high-speed digital dial-up service that uses the standard PSTN infrastructure. It is used primarily for Internet connections, but it also supports special devices such as ISDN telephones and fax machines. The Basic Rate Interface (BRI) provides two64-Kbps B channels and one 16-Kbps D channel. The Primary Rate Interface (PRI) provides Kbps B channels and one 64-Kbps D channel. For computer connections, ISDN requires a Network Terminator 1 (NT-1) and a terminal adapter.
DSL Service Types ServiceTransmission RateLink Length Applications High-bit-rate Digital Subscriber Line (HDSL) Mbps full-duplex (using two wire pairs) or Mbps full-duplex (using three wire pairs) 12,000 to 15,000 feet Used by large networks as a substitute for T-1 leased line connections, LAN and private branch exchange (PBX) interconnections, or frame relay traffic aggregation Symmetrical Digital Subscriber Line (SDSL) Mbps full-duplex or Mbps full-duplex (one wire pair) 10,000 feet Same as HDSL Asymmetrical Digital Subscriber Line (ADSL) to Mbps downstream; 16 Kbps to 640 Kbps upstream 10,000 to 18,000 feet Internet/intranet access, remote LAN access, virtual private networking, video on demand, Voice over IP
CATV Networks Broadband networks owned by cable television companies Provide Internet access through the same cable used for television signals Run at 512 Kbps or more Bandwidth shared with other users in the area Provide Internet connections only
Satellite Connections Provide Internet access only Usually downstream only Require a dial-up connection for upstream traffic
PPP Stands for Point-to-Point Protocol Used for dial-up Internet connections and other wide area network (WAN) technologies
What Is Fault Tolerance? Depending on the organization, an equipment failure or other service interruption can mean lost productivity, lost revenue, and sometimes lost lives. Fault-tolerance mechanisms enable a computer or a network to continue operating despite the failure of a major component. When network functions are absolutely critical, the fault-tolerance mechanisms can be elaborate. In most cases, however, fault-tolerance mechanisms protect only a few key components from outages due to hardware or software faults.
Mirroring Mirroring is an arrangement in which two identical hard drives connected to a single host adapter always contain identical data. The two drives appear to users as one logical drive. Whenever users save data to the mirror set, the computer writes it to both drives simultaneously. If one hard drive unit fails, the other takes over immediately until the malfunctioning drive is replaced.
RAID Redundant array of independent disks (RAID) is a comprehensive data availability technology with various levels that provide all of the functions of mirroring, duplexing, volumes, and disk striping. Although RAID is available as a software product that works with standard disk drives, many high-end servers use dedicated RAID drive arrays, which Consist of multiple hard drive units in a single housing Often have hot swap capability Hot swapping is the ability to remove and replace a malfunctioning drive without shutting off the other drives in the array, so the data is continuously available to network users during the drive repair.
RAID Levels LevelTechnologyFunction 0Disk stripingEnhances performance by writing data to multiple disk drives, one block at a time; provides no fault tolerance. 1Disk mirroring and duplexing Provides fault tolerance by maintaining duplicate copies of all data on two drives. Disk mirroring uses two drives connected to the same host adapter, and disk duplexing uses two drives connected to different host adapters. 2Hamming error- correcting code (ECC) Ensures data integrity by writing error-correcting code to a separate disk drive; rarely implemented. 3Parallel transfer with shared parity Provides fault tolerance by striping data at the byte level across a minimum of two drives and storing parity information on a third drive. If one of the data drives fails, its data can be restored by using the parity information.
RAID Levels (Cont.) LevelTechnologyFunction 4Independent data disks with shared parity Identical to RAID 3, except that the data is striped across the drives at the block level. 5Independent data disks with distributed parity Provides fault tolerance by striping both data and parity across three or more drives instead of using a dedicated parity drive, as in RAID 3 and RAID 4. 6Independent disks with two- dimensional parity Provides additional fault tolerance by striping data and two complete copies of the parity information across three or more drives. 7Asynchronous RAID Proprietary hardware solution that consists of a striped data array and a separate parity drive, plus a dedicated operating system that coordinates the disk storage activities.
NAS Network attached storage (NAS) uses a dedicated storage appliance that connects directly to the network and contains its own embedded operating system. NAS is essentially a multiplatform file server. Computers on the network can access the NAS appliance in a variety of ways.
SANs A Storage Area Network (SAN) is a separate network installed at a local area network (LAN) site that connects servers to disk arrays and other network storage devices. SANs make it possible to use dedicated storage hardware arrays without overloading the client network with storage-related traffic. SANs typically use the Fibre Channel protocol to communicate, but they can theoretically use any network medium and protocol.