Course glossary
Networking terms, in context.
Definitions for terms used in How Networks Work. Each one points back to the session where it becomes useful.
- ARP
- Address Resolution Protocol maps an IPv4 address on the local link to a link-layer address.
- Why it matters: Ethernet needs a destination MAC address. Act 1, Session 5.
- MAC address
- A link-layer identifier carried in an Ethernet frame.
- Why it matters: switches learn and forward using these addresses. Act 1, Session 4.
- Frame
- A unit of link-layer data, such as Ethernet, that can carry an IP packet.
- Act 1, Session 4.
- Packet
- A unit of network-layer data. An IP packet carries transport data between IP endpoints.
- Act 1, Session 1.
- Route
- A rule that tells a host or router which interface and next hop to use for matching destinations.
- Act 2, Session 7.
- Default gateway
- The next-hop router used when no more-specific route matches a destination.
- Act 1, Session 2.
- NAT
- Network Address Translation rewrites address information and often ports while tracking a flow.
- Act 2, Session 8.
- Port
- A transport-layer number that helps TCP or UDP deliver data to the right application endpoint.
- Act 2, Session 9.
- TCP
- A connection-oriented transport protocol that provides an ordered, reliable byte stream.
- Act 2, Sessions 9 and 10.
- DNS
- The Domain Name System maps names to records through a distributed, cached system.
- Act 2, Session 11.
- TLS
- A protocol that authenticates peers and protects application data in transit.
- Act 2, Session 12.
- Certificate
- A signed document that binds identity information to a public key, subject to validation rules.
- Act 2, Session 12.
- Firewall
- A policy enforcement point that permits or blocks traffic using packet and connection state.
- Act 3, Session 14.
- Load balancer
- A system that distributes connections or requests across available backends.
- Act 3, Session 15.
- Autonomous system
- A network or group of networks operated under one routing policy and identified by an ASN.
- Act 3, Session 17.
- BGP
- The Border Gateway Protocol exchanges reachability and path information between routing systems.
- Act 3, Sessions 17 and 18.