Networking Review
Networking is complicated! This Networking Review series is my attempt to review and demystify some of its concepts.
The content of this series is mostly based on Computer Networking: A Top-Down Approach (6th Edition).
High Level
Internet Service Providers (ISP) provide internet access for end devices. ISPs themselves must inter-connect with each other. In reality, Internet is a network of networks, in which there are several 1-tier-ISPs (AT&T, CenturyLink…) inter-connecting with each other.
Packet Switches
Packets travel from one machine to another typically go through packet switches. They are usually either a router or a layer-2 switch.
routers are used in core-networks while layer-2 switches are used in home-networks.
Routers have a forwarding table which maps the destination IP of an incoming packet on one interface to one of its other network interfaces.
How is this routing table get set? It is done by routing protocols.
OSI Model (Top Down)
- Application
- Presentation
- Session
- Transport
- Network
- Data Link
- Physical