COMPUTER NETWORKS
 COURSE 5 ALEX PALCUIE 

COMPUTER NETWORKS - COURSE 5 OUTLINE ▸ switch vs router ▸ MAC address vs IP address ▸ DNS, SSH, HTTP, Ethernet, Wi-Fi 

https://xkcd.com/422/ 

2 COMPUTERS DEMO (NO WI-FI) 

COMPUTER NETWORKS - COURSE 5 NETWORK INTERFACE CONTROLLER ▸ A network interface controller (NIC, also known as a network interface card, network adapter, LAN adapter or physical network interface and by similar terms) is a computer hardware component that connects a computer to a computer network. 

COMPUTER NETWORKS - COURSE 5 MEDIA ACCESS CONTROL ADDRESS (MAC) ▸ A media access control address (MAC address), also called physical address, is a unique identifier assigned to network interfaces for communications on the physical network segment. MAC addresses are used as a network address for most IEEE 802 network technologies, including Ethernet and WiFi. 

COMPUTER NETWORKS - COURSE 5 ETHERNET ▸ Ethernet is a family of computer networking technologies for local area networks (LANs) and metropolitan area networks (MANs). It was commercially introduced in 1980 and first standardized in 1983 as IEEE 802.3, and has since been refined to support higher bit rates and longer link distances. 

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COMPUTER NETWORKS - COURSE 5 IP ADDRESS ▸ An Internet Protocol address (IP address) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication. An IP address serves two principal functions: host or network interface identification and location addressing. Its role has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there." 

COMPUTER NETWORKS - COURSE 5 PRIVATE IP ADDRESS RANGES ▸ 127.0.0.1 - localhost ▸ 192.168.0.0 - 192.168.255.255 ▸ 172.16.0.0 - 172.31.255.255 ▸ 10.0.0.0 - 10.255.255.255 

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COMPUTER NETWORKS - COURSE 5 ADDRESS RESOLUTION PROTOCOL (ARP) ▸ Telecommunication protocol used for resolution of network layer addresses into link layer addresses, a critical function in multiple-access networks. ARP was defined by RFC 826 in 1982. 

COMPUTER NETWORKS - COURSE 5 INTERNET CONTROL MESSAGE PROTOCOL (ICMP) ▸ One of the main protocols of the Internet Protocol Suite. It is used by network devices, like routers, to send error messages indicating, for example, that a requested service is not available or that a host or router could not be reached. ▸ Ping is a computer network administration software utility used to test the reachability of a host on an Internet Protocol (IP) network and to measure the round-trip time for messages sent from the originating host to a destination computer and back. ▸ Smurf attack ▸ traceroute 

http://xkcd.com/1077/ 

N COMPUTERS + SWITCH DEMO 

COMPUTER NETWORKS - COURSE 5 SWITCH ▸ A network switch (also called switching hub, bridging hub, officially MAC bridge) is a computer networking device that connects devices together on a computer network, by using packet switching to receive, process and forward data to the destination device. Unlike less advanced network hubs, a network switch forwards data only to one or multiple devices that need to receive it, rather than broadcasting the same data out of each of its ports. 

ROUTER + INTERNET DEMO 

COMPUTER NETWORKS - COURSE 5 DOMAIN NAME SYSTEM (DNS) ▸ Hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. Most prominently, it translates domain names, which can be easily memorized by humans, to the numerical IP addresses needed for the purpose of computer services and devices worldwide. The Domain Name System is an essential component of the functionality of most Internet services because it is the Internet's primary directory service. 

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https://www.iana.org/domains/root/servers 

https://xkcd.com/1361/ 

COMPUTER NETWORKS - COURSE 5 HYPERTEXT TRANSFER PROTOCOL (HTTP) ▸ The Hypertext Transfer Protocol (HTTP) is an application protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web. ▸ Hypertext is structured text that uses logical links (hyperlinks) between nodes containing text. HTTP is the protocol to exchange or transfer hypertext. 

INTERNET VS WEB 

COMPUTER NETWORKS - COURSE 5 GOPHER PROTOCOL ▸ The Gopher protocol is a TCP/IP application layer protocol designed for distributing, searching, and retrieving documents over the Internet. The Gopher protocol was strongly oriented towards a menu-document design and presented an alternative to the World Wide Web in its early stages, but ultimately HTTP became the dominant protocol. The Gopher ecosystem is often regarded as the effective predecessor of the World Wide Web. 

COMPUTER NETWORKS - COURSE 5 TRANSMISSION CONTROL PROTOCOL (TCP) ▸ Core protocol of the Internet protocol suite. It originated in the initial network implementation in which it complemented the Internet Protocol (IP). Therefore, the entire suite is commonly referred to as TCP/IP. TCP provides reliable, ordered, and error-checked delivery of a stream of octets between applications running on hosts communicating over an IP network. TCP is the protocol that major Internet applications such as the World Wide Web, email, remote administration and file transfer rely on. 

COMPUTER NETWORKS - COURSE 5 USER DATAGRAM PROTOCOL (UDP) ▸ UDP uses a simple connectionless transmission model with a minimum of protocol mechanism. It has no handshaking dialogues, and thus exposes the user's program to any unreliability of the underlying network protocol. There is no guarantee of delivery, ordering, or duplicate protection. UDP provides checksums for data integrity, and port numbers for addressing different functions at the source and destination of the datagram. 

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ROUTER WIFI + INTERNET DEMO 

COMPUTER NETWORKS - COURSE 5 WIFI (IEEE 802.11 B/G/N/AC) ▸ Wi-Fi (or WiFi) is a local area wireless computer networking technology that allows electronic devices to network, mainly using the 2.4 gigahertz (12 cm) UHF and 5 gigahertz (6 cm) SHF ISM radio bands. 

COMPUTER NETWORKS - COURSE 5 DYNAMIC HOST CONFIGURATION PROTOCOL (DHCP) ▸ The Dynamic Host Configuration Protocol (DHCP) is a standardized network protocol used on Internet Protocol (IP) networks for dynamically distributing network configuration parameters, such as IP addresses for interfaces and services. With DHCP, computers request IP addresses and networking parameters automatically from a DHCP server, reducing the need for a network administrator or a user to configure these settings manually. 

COMPUTER NETWORKS - COURSE 5 WI-FI PROTECTED ACCESS II (WPA2) ▸ Wi-Fi Protected Access (WPA) and Wi-Fi Protected Access II (WPA2) are two security protocols and security certification programs developed by the Wi-Fi Alliance to secure wireless computer networks. The Alliance defined these in response to serious weaknesses researchers had found in the previous system, Wired Equivalent Privacy (WEP). 

https://xkcd.com/936/ 

https://xkcd.com/1457/ 

http://www.extremetech.com/wp-content/uploads/2014/03/1000px-2.4_GHz_Wi- Fi_channels_802.11bg_WLAN.svg_.png 

COMPUTER NETWORKS - COURSE 5 SERVICE SET ID (SSID) ▸ In computer networking, a service set is a set consisting of all the devices associated with a consumer or enterprise IEEE 802.11 wireless local area network (WLAN). The service set can be local, independent, extended or mesh. ▸ Service sets have an associated identifier, the Service Set Identifier (SSID), which consists of 32 octets that frequently contains a human readable identifier of the network. 

ROUTER WIFI + SWITCH + INTERNET DEMO 

SECURITY 

QUESTIONS GITHUB.COM/PALCU/COMNETWORKS-LAB