network layers

Work in Progress

Summary

Building the packet

Layer	Packet format	Needs
application layer	message	the data itself
transport layer	segment -> src & dest ports \| message	which port/process to send to
network layer	datagram -> src & dest ip \| segment	which host to send to

each successive layer builds upon the packet

Concept

Protocols

format and order of messages exchanged
actions taken upon receiving/sending

Protocol layers

built upon layers of abstraction, upper layers do not need to deal with the physical connection directly
all communication still goes through the physical layer

Application layer

application to application
protocols used by internet applications running on hosts
HTTP, DNS, FTP, SMTP

Architecture	Desc
client-server	- server: listens and waits, provides a service - client: initiates contact
peer to peer(P2P)	- end hosts communicate directly - scalable: new users add more capacity - difficult to manage
hybrid	- central server helps to link end hosts
Requirements

data integrity: file transfer requires lossless; streaming can tolerate data loss
timing: games need low latency
throughput: multimedia requires minimum amount of bandwidth to be effective
security: encryption, authentication

Transport layer

process to process
runs on the host itself
TCP. UDP

Stakeholder	Role
sender	break message into segments
receiver	reassemble segment into messages
routers	inspect dest ip and route

ususally, routers are in the network layer

Network layer

host to host
best-effort and unreliable
DHCP

Extra

Tikz template for protocol diagrams