Presentation on theme: "Chapter 10 Intro to Routing & Switching. Upon completion of this chapter, you should be able to: Explain how the functions of the application layer,"— Presentation transcript:
Upon completion of this chapter, you should be able to: Explain how the functions of the application layer, session layer, and presentation layer work together to provide network services to end user applications. Describe how common application layer protocols interact with end user applications. Describe common application layer protocols that provide Internet services to end-users, including WWW services and email. Describe application layer protocols that provide IP addressing services, including DNS and DHCP. Describe the features and operation of well-known application layer protocols that allow for file sharing services. Explain how data is moved across the network, from opening an application to receiving data.
Provides the interface between the applications we use to communicate & the network Used to exchange data between source & destination What are some of the application layer protocols?
Formats data so it can be read Compress/decompress data Encrypt/decrypt data MPEG, JPG, GIF
DNS Names to IP addresses Telnet Remote access to servers/switches/routers/devices DHCP Automatically assign IP/SM/DG/DNS server addresses BOOTP Older version of DHCP
HTTP Transfers web pages FTP File transfer SMTP Transfers email POP Gets email from email server to client Then deleted from server IMAP Gets email from email server to client Kept on server until you delete it
What 3 OSI layers are similar to the TCP/IP Application Layer? Application, Presentation, Session What are 3 functions of the Presentation Layer? Data formatting, compression, encryption Name some application layer protocols. DNS, DHCP, Telnet, POP, IMAP, SMTP, FTP, HTTP, BOOTP What protocol handles web transfer? HTTP What protocol handles file transfer? FTP
2 or more connected computers with NO SERVER Shares files on each other’s HD & connected printers Every device acts as client AND server No one device in charge No central user accounts
P2P applications allow users to directly share specified file types across peer-to-peer or client-server networks.
BitTorrent LimeWire No central server Uses files found on client hard drives
Client requests a service from a dedicated server
What type of network has centralized resources, such as central file storage? Client-server What type of network shares resources located on local computer hard drives? Peer to peer You type www.gcit.org into your web browser. A DNS request is created and then a we request is sent. What type of network is this?www.gcit.org Client-server
What application layer protocols would you use on a daily basis?
http://www.cisco.com/index.html http://www.cisco.com/index.html HTTP is the protocol Cisco.com is the server name Index.html is the document you requested
Layer 4 port: HTTP: 80 HTTPS: 443 Browser messages GET (requests page from web server) POST & PUT (uploads to web server) HTTPS Secure Uses SSL to encrypt
Layer 4 ports: SMTP-25 POP3- 110 IMAP-143 Send mail to server & server to server; SMTP Get mail from email server; POP3 & IMAP POP deletes mail from server when sent to client IMAP sends copy of email to client and server keeps mail until deleted
PT Lab 10.2.1.8 Web & Email In this activity, you will configure HTTP and email services using the simulated server in Packet Tracer. You will then configure clients to access the HTTP and email services.
Why would you use IMAP instead of POP? IMAP keeps the emails until manually deleted Which protocol uses GET, PUT, and POST? HTTP Which email protocol send you a copy of the email and deletes it from the server? POP What port # is POP? 110 What does HTTPS use to encrypt? SSL
Layer 4 port: 53 Servers that translates names to IP addresses DNS servers know some, forward rest to other DNS servers Nslookup Get in the mode and then enter domain Ipconfig /displaydns Displays cached DNS
DNS servers are in a hierarchy Top-level, most trusted:.com,.edu,.gov Contains 2 nd -level domain server records Second-level: Contains records for the company only MX used for mail
Layer 4 port: 67/68 At home, your router is a DHCP server At work, you may have a dedicated DHCP server Used for general purpose/PC devices Static addressing for routers, switches, printers, Internet-accessible devices DHCP addresses are leased
PT Lab 10.2.2.8 DHCP & DNS Services In this activity, you will configure and verify static IP addressing and DHCP addressing. You will then configure a DNS server to map IP addresses to the website names. HW: Lab 10.2.2.9 Observing DNS You will observe the DNS Conversion of a URL to an IP Address, observe DNS Lookup Using the nslookup Command on a Web Site, and observe DNS Lookup Using the nslookup Command on Mail Servers.
Which broadcast message gets sent out from a PC to a DHCP server when it turns on? DCHPDiscover What does the DHCP server send back to the PC? DHCPOffer What does the DHCP request look like? All 255’s Who gets & responds to that request? Everyone in local network gets it; only DHCP server responds
Server Message Block Client-server file sharing protocol for file, printer, and directory sharing Used for long-term connections to keep connection active Authenticates the session Example: Use SMB (instead of FTP) when downloading a TON of files from a server
PT Lab 10.2.3.2 In this activity, you will configure FTP services. You will then use the FTP services to transfer files between clients and the server.
What program runs on an FTP server that listens for requests? FTPdaemon What runs on a PC that will request services from an FTP server? FTP Client software If you need to download many files from a server, which could take hours, which protocol would you use? SMB
Which command did you use to manually get the name to IP information? nslookup What port is HTTPS? 443 What type of applications need a specific application interface and background service running between hosts? P2P application, like IM
Applications are computer programs with which the user interacts and which initiate the data transfer process at the user’s request. Services are background programs that provide the connection between the application layer and the lower layers of the networking model. Protocols provide a structure of agreed-upon rules and processes that ensure services running on one particular device can send and receive data from a range of different network devices
HTTP supports the delivery of web pages to end devices SMTP, POP, and IMAP support sending and receiving email FTP enable users to share files P2P applications make it easier for consumers to seamlessly share media DNS resolves the human legible names used to refer to network resources into numeric addresses usable by the network All of these elements work together, at the application layer. The application layer enables users to work and play over the Internet.
Complete the study guide handout Take the quiz on netacad.com Jeopardy review