Chapter 10 Intro to Routing & Switching

 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 .  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.

10.1

 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  POP  Gets from server to client  Then deleted from server  IMAP  Gets from 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

10.1.1

 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 into your web browser. A DNS request is created and then a we request is sent. What type of network is this?  Client-server

10.2.1

 What application layer protocols would you use on a daily basis?

  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  POP  IMAP-143  Send mail to server & server to server; SMTP  Get mail from server; POP3 & IMAP  POP deletes mail from server when sent to client  IMAP sends copy of to client and server keeps mail until deleted

 PT Lab Web &  In this activity, you will configure HTTP and services using the simulated server in Packet Tracer. You will then configure clients to access the HTTP and services.

 Why would you use IMAP instead of POP?  IMAP keeps the s until manually deleted  Which protocol uses GET, PUT, and POST?  HTTP  Which protocol send you a copy of the and deletes it from the server?  POP  What port # is POP?  110  What does HTTPS use to encrypt?  SSL

10.2.2

 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  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  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

10.2.3

 Layer 4 port: 20/21  20- data  21- control info  Download/upload data from a server  Example: sending a designed web page to the web server

 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  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  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

Chapter 10 Intro to Routing & Switching