Week 1: Subnet Refresher

Week 1: 8/29/22

  • Dartmouth had hundreds of subnets just in the datacenter

  • 2^32 IPv4 addresses | 32 bits

Letter
Packet
  1. Look up recipient address

    1. Phone Book? Other Directory?

    2. Get zip code and street address

  2. Put in addressed envelope

    1. Write recipient and return address on envelope

  3. Put letter in mailbox

  4. Mail carrier picks letter up

    1. Take letter to local post office

  5. Post Office sorts and sends to next PO facility

    1. Uses zip code

  6. How does PO know where to send next?

    1. Postal Service has “routing lists”

  7. Ends up at local PO recipient

  8. Mail Carrier delivers to recipient

    1. Uses street address

  1. Look up recipient address

    1. Domain Name System (DNS)

    2. Convert Hostname to IP address

  2. Add “Headers” to data (encapsulate)

  3. Send packet to network interface controller (NIC)

  4. Transmits onto network

    1. Sent to local router (AKA default gateway)

  5. Router sends packet to next router

    1. Uses network part of the IP Address

  6. How does the router know where to send next?

    1. “Routing table” of IP networks

  7. Ends up at local router of recipient

  8. Router and switches send to recipient

    1. Uses Host part and IP address and Mac address`

TODO:

  • Download Packet Tracer 8.1.1

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