CompTIA Network+ (N10-009) Glossary
Keep the core N10-009 networking vocabulary straight with a compact glossary of high-confusion terms.
On this page
Use this glossary when Network+ terms blur together. Keep it beside the lesson pages rather than using it as a substitute for them.
| Term | Short meaning |
|---|---|
| APIPA | IPv4 self-assignment in the 169.254.0.0/16 range when DHCP fails |
| Anycast | One logical destination announced from multiple locations so traffic goes to the closest path |
| AAA | Authentication, authorization, and accounting for access-control workflows |
| CIDR | Prefix-length notation such as /24 or /64 |
| FHRP | Default-gateway redundancy mechanism |
| IPAM | Address-management inventory and control system |
| Jitter | Variation in delay that hurts voice and other time-sensitive traffic |
| MTBF | Mean time between failures |
| MTTR | Mean time to repair or restore |
| NAT | Address translation at a network boundary |
| Out-of-band management | An admin path that can still work when the main production path is impaired |
| PAT | Port-based form of NAT that lets many devices share one public address |
| PBQ | Performance-based question |
| PDU | The data object handled at a given protocol layer |
| PKI | Certificate and trust-chain system used for identity and encryption |
| PoE | Power over Ethernet |
| RPO | Maximum acceptable data-loss window |
| RTO | Target time to restore service |
| SLAAC | IPv6 self-addressing from router advertisements |
| SPAN | Port mirroring for traffic inspection |
| SSID | Wireless network name |
| STP | Loop-prevention mechanism for switched networks |
| TDR | Cable-testing method that helps locate faults along a copper run |
| TACACS+ | AAA protocol commonly used for device administration |
| VPC | Logically isolated cloud network |
| VLAN | Logical Layer 2 segmentation boundary |
Commonly confused pairs
| Pair | Keep this distinction clear |
|---|---|
| threat vs vulnerability | threat is the danger or actor, vulnerability is the weakness |
| exploit vs impact | exploit is the attack path, impact is what got harmed |
| baseline vs backup | baseline is intended approved state, backup is recoverable saved state |
| unicast vs multicast | unicast is one-to-one, multicast is one-to-many for subscribed receivers |
| out-of-band vs in-band management | out-of-band stays usable even when the normal production path is impaired |
Fast recall anchors
| If you keep mixing up… | Use this anchor |
|---|---|
| DNS vs DHCP | names versus addressing |
| NAT vs PAT | translation generally versus many hosts sharing one address |
| RTO vs RPO | restore time versus acceptable data-loss window |
| latency vs jitter | delay versus variation in delay |
| TACACS+ vs RADIUS | device-admin focus versus broader network-access AAA fit |
Best chapter to revisit by term family
| If the term is really about… | Revisit this chapter |
|---|---|
| layers, media, protocols, topology, or addressing | 1. Networking Concepts |
| routing, VLANs, wireless deployment, or installs | 2. Network Implementation |
| documentation, change, backups, services, or remote management | 3. Network Operations |
| controls, risk, compliance, segmentation, or attacks | 4. Network Security |
| symptoms, tools, and fault isolation | 5. Network Troubleshooting |
If a term keeps costing you points, jump back to the exact lesson page rather than rereading this glossary repeatedly.