OSI Model
Back to Networking
It is a view of networking that breaks down the layers of abstraction. Essentially, several layers of conventions on how to wrap data with metadata and the protocols for unwrapping.
5-7 Application & Upper Layer Data
These are the highest level of abstraction, generally deal with encryption & compression
- HTTP, HTTPS, FTP, SSH
- BGP, for modifying route tables (poisoning or adding routes)
At 6, SSL/TLS, ASCII, JPG
4 Transport
TCP, UDP sends Segment datagrams
- these are protocols that work on the assumption that messages make it to the right computer
- this layer exists for data integrity, where TCP further extends this to ensuring data is received
- includes ports
3 Network
IPv4, IPv6, ICMP.
- Packet datagrams
- this is where routing is handled, route tables and rules
- ICMP is used for pings, traceroute
- diagnostics, error messages or control messages to provide feedback about the control environment
- it could be done with IP packets, but would have required more length for each packet
2 Data Link
Ethernet protocol, WiFi protocol, amongst others. Each frame wraps informations around each data payload. This layer's responsibility is making a connection and ensuring error free transfer
- ARP is a protocol for discovering MAC address associated with an IPv4 address (or other layer 3 address)
1 Physical
Bits over cables. Electrical specs.