Week8 final

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    07-Aug-2015
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Transcript of Week8 final

  1. 1. Lecture 8 Networks (contd.)
  2. 2. Recap of Network lectures
  3. 3. how works? (campus, metropolitan, home) (server-based, peer-to-peer) (core, access) (intranet, internet, extranet, VPN) (packet switching) (cell switching) (dial-up) (DSL, Cable, WiMax) Todays lecture outline
  4. 4. How email works? 1
  5. 5. User sends email SMTP data Source MAC address | Destination MAC address 23:34:aa:bb:cc:dd | 12:34:aa:bb:cc:dd FCSPayload PayloadSource Port | Destination Port > 1024 | 25 Payload PayloadSource IP | Destination IP 202.125.157.150 | 115.186.131.69 Payload Application layer Transport layer Link layer Internet layer
  6. 6. This is a mail client software (e.g., Outlook Express (shown); Mozilla Thunderbird) Compare with browser software: (Internet explorer; Mozilla Firefox) Webmail.niit.edu.pk Webmail.niit.edu.pk
  7. 7. User receives email POP request Source MAC address | Destination MAC address 23:34:aa:bb:cc:dd | 12:34:aa:bb:cc:dd FCSPayload PayloadSource Port | Destination Port > 1024 | 110 (POP) Payload PayloadSource IP | Destination IP 202.125.157.150 | 115.186.131.69 Payload Application layer Transport layer Link layer Internet layer or IMAP requestor HTTP request Source Port | Destination Port > 1024 | 143 ( if IMAP) Source Port | Destination Port > 1024 | 80 ( if HTTP) or IMAP requestor HTTP request
  8. 8. Classification of Networks 2
  9. 9. (Geographical Scope)Classification Wide Area Networks Metropolitan Area Networks Campus Area Networks Home Area Networks Personal Area Networks
  10. 10. (Network Paradigm)Classification Client-server networks: Examples: DNS, HTTP, DBMS servers and client
  11. 11. (Network Paradigm)Classification Peer-to-peer (P2P) networks: Examples: Workgroup computing; P2P networks such as BitTorrent, Gnutella, Morpheus, etc.
  12. 12. (Hierarchy)Classification Core Distribution Access
  13. 13. (Type)Classification VPN Image source: http://www.flexsys-group.com Extranet Internet
  14. 14. Network technologies 3
  15. 15. Multi-protocol label switching (MPLS) Packet based Unified data-carrying service for both circuit-based and packet-based clients Asynchronous Transfer Mode (ATM) Cell (small fixed sized packets) based Both ATM and MPLS allow traffic engineering Core network technologies
  16. 16. Uses analog telephone lines Utilizes a modulator/ demodulator (Modem) Modems perform error correction/ compression V.34 (28.8, 33.6 kbps); V.90 and V.92 (56 kbps) Telephone networks limit a single narrowband channel to 56 kbps (Narrowband)Access technology
  17. 17. Leased Circuits: E1 (2M), E2 (8M), E3 (34M) DSL: Utilizes telephone lines but performs efficient digital coding Types: ADSL, HDSL, SDSL, VDSL Cable: Utilizes co-axial cables and provides similar access speeds to DSL WiMax: Wireless broadband technology (Broadband)Access technology
  18. 18. http://tinyurl.com/5hb8pp