---
# System prepended metadata

title: TCP/IP

---

# TCP/IP

1. Internet: “network of networks” • Interconnected ISPs
2.Protocols define the format, order of messages sent and received among network entities, and actions taken on msg transmission, receipt.
3.  protocols are everywhere
• control sending, receiving of messages
• e.g., HTTP (Web), streaming video, Skype, TCP, IP, WiFi, 4G, Ethernet
3. Internet standards
• RFC: Request for Comments
• IETF: Internet Engineering Task Force

## Internet Structure
### Network edge:
  - hosts: clients and servers 
  - servers often in data centers
### Access networks, physical media:
  - wired, wireless communication links
### Network core:
  - interconnected routers
  - network of networks

![Screenshot 2023-11-09 at 3.52.03 PM](https://hackmd.io/_uploads/rJytIacX6.png)
![Screenshot 2023-11-09 at 3.56.02 PM](https://hackmd.io/_uploads/SJrcPp5X6.png)
![Screenshot 2023-11-09 at 3.57.06 PM](https://hackmd.io/_uploads/S1psDTqmT.png)
![Screenshot 2023-11-09 at 4.02.43 PM](https://hackmd.io/_uploads/rJxWKaqXa.png)


## Delays
![Screenshot 2023-11-09 at 4.04.14 PM](https://hackmd.io/_uploads/ryKIKTcmp.png)
![Screenshot 2023-11-09 at 4.04.49 PM](https://hackmd.io/_uploads/HkCOtpq7p.png)
![Screenshot 2023-11-09 at 4.05.06 PM](https://hackmd.io/_uploads/H1pFF65Xa.png)

## Delays & Queueing
![Screenshot 2023-11-09 at 4.08.03 PM](https://hackmd.io/_uploads/H1kH96qQp.png)

## Traceroute
Traceroute program: provides delay measurement from source to router along end-end Internet path towards destination.

## Throughput
![Screenshot 2023-11-09 at 4.12.05 PM](https://hackmd.io/_uploads/HJ7Vj65X6.png)

![Screenshot 2023-11-09 at 4.13.45 PM](https://hackmd.io/_uploads/HJN5iTq7a.png)

## Encapsulation
Encapsulation in TCP/IP is the process of adding headers and trailers around some data1234. The headers contain additional information about the data and are added by each layer of the TCP/IP model. The headers are used for exchanging control and status information about the progress of the communication. When data moves from upper layer to lower layer of TCP/IP protocol stack, during an outgoing transmission, each layer includes a bundle of relevant information called "header" along with the actual data.

![Screenshot 2023-11-09 at 4.37.13 PM](https://hackmd.io/_uploads/r1Nf-0qQ6.png)


Persistent vs Non-persistent
![Screenshot 2023-11-09 at 5.56.53 PM](https://hackmd.io/_uploads/B1QTmko7p.png)

![Screenshot 2023-11-09 at 5.57.22 PM](https://hackmd.io/_uploads/rkpCQks7p.png)
![Screenshot 2023-11-09 at 5.58.31 PM](https://hackmd.io/_uploads/SybXV1jX6.png)
![Screenshot 2023-11-09 at 5.58.41 PM](https://hackmd.io/_uploads/ryoX4ys76.png)


# Cache
![Screenshot 2023-11-09 at 5.59.30 PM](https://hackmd.io/_uploads/B12LEkjX6.png)
![Screenshot 2023-11-09 at 6.00.52 PM](https://hackmd.io/_uploads/ry1nEysQ6.png)


# Email
![Screenshot 2023-11-09 at 6.02.05 PM](https://hackmd.io/_uploads/BygWryiQp.png)
![Screenshot 2023-11-09 at 6.02.20 PM](https://hackmd.io/_uploads/rJUZHyi76.png)
![Screenshot 2023-11-09 at 6.02.40 PM](https://hackmd.io/_uploads/BkcfHkomp.png)
![Screenshot 2023-11-09 at 6.02.49 PM](https://hackmd.io/_uploads/B17mrJjmp.png)

# DNS
![Screenshot 2023-11-09 at 4.37.13 PM](https://hackmd.io/_uploads/r1Nf-0qQ6.png)

# Sockets
![Screenshot 2023-11-09 at 6.09.56 PM](https://hackmd.io/_uploads/rJGA81jXT.png)

![Screenshot 2023-11-09 at 6.10.55 PM](https://hackmd.io/_uploads/HklGPJiXa.png)

