Week 1: Subnet Refresher
- Dartmouth had hundreds of subnets just in the datacenter
- 2^32 IPv4 addresses | 32 bits
| Letter | Packet |
|---|
- Look up recipient address
- Phone Book? Other Directory?
- Get zip code and street address
- Put in addressed envelope
- Write recipient and return address on envelope
- Put letter in mailbox
- Mail carrier picks letter up
- Take letter to local post office
- Post Office sorts and sends to next PO facility
- Uses zip code
- How does PO know where to send next?
- Postal Service has “routing lists”
- Ends up at local PO recipient
- Mail Carrier delivers to recipient
- Uses street address
| - Look up recipient address
- Domain Name System (DNS)
- Convert Hostname to IP address
- Add “Headers” to data (encapsulate)
- Send packet to network interface controller (NIC)
- Transmits onto network
- Sent to local router (AKA default gateway)
- Router sends packet to next router
- Uses network part of the IP Address
- How does the router know where to send next?
- “Routing table” of IP networks
- Ends up at local router of recipient
- Router and switches send to recipient
- Uses Host part and IP address and Mac address`
|
- grandma@aol.com
- ^Mailbox ^ Mail server → translates to ip address
TODO:
- Download Packet Tracer 8.1.1