Network plus 1900

DDoS (Distributed Denial of Service)

Attacking all at once from multiple offensive locations to overload a system and gain entry.

Trojan

Malware that pretends to be something safe so you install it yourself.

Spyware Traffic Behavior

Sends smaller amounts of data over long periods, often without generating an immediate, noticeable spike in traffic.

BitLocker

Microsoft’s built-in tool that encrypts the entire drive to prevent data theft if a laptop or hard drive is stolen.

RBAC (Role-Based Access Control)

An access-control model where permissions are based on a person’s role, not the individual person.

Switch Virtual Interface (SVI)

Acts as the VLAN's default gateway inside a switch; allows devices to reach other networks and manage the switch remotely.

Outbound Traffic Firewall Behavior

Stateful (Automatic tracking when an internal device sends traffic).

Inbound Traffic Firewall Behavior

Stateless (Requires manual rules for both directions when traffic originates from the outside).

IP Address Prefix Length

Represents the portion of the IP address that specifies the network.

Main drawback of NAT (Network Address Translation)

It breaks end-to-end connectivity.

Maximum Transmission Unit (MTU) & Default Size

The biggest packet a link can handle (1500 bytes default). Anything bigger must be fragmented.

Cyclic Redundancy Check (CRC)

Detects errors in frames/packets across a link. Layer 1 causes the error, but Layer 2 detects it.

Packet Scheduling

The method a device uses to choose the next packet to transmit from a queue (High-priority traffic is sent first).

Traffic Shaping

Delays packets by buffering and releasing them at a controlled speed to stay within a desired rate. Never drops packets.

Round Trip Time (RTT)

The time it takes for a packet to travel from source to destination AND back. Measures latency, not bandwidth.

High Latency Primary Cause

Delays in packet delivery, with routing issues being one of the biggest causes.

NAT Gateway

The cloud version of NAT. Provides powerful, highly available, and automatically scaled outbound internet access for private subnets without exposing private IPs.

Fibre Channel (FC)

High-speed, low-latency storage networking technology used in data centers to connect servers to Storage Area Networks (SANs).

Active-Active System

Two or more systems working at the exact same time, sharing the network or processing load.

SCADA (Supervisory Control And Data Acquisition)

A system that lets operators monitor and control large industrial equipment from far away.

Root Bridge

The "boss switch" or main reference point all switches use to calculate paths. The switch with the lowest Bridge ID wins.

RSTP (Rapid Spanning Tree Protocol) Port Roles

Faster version of STP. Uses 4 rules: Root port, Designated port, Alternate port (failsafe for root), and Backup port.

SNMP Polling vs. Trap

Polling asks the device for information. A Trap is an alert sent automatically by the device when something happens.

Management Information Base (MIB)

A dictionary or menu listing all the specific data points you can ask a device for using SNMP.

DHCP Traffic Flow (DORA)

Discover ➔ Offer ➔ Request ➔ Acknowledge.

IEEE 802.3

Ethernet

IEEE 802.11

Wi-Fi

802.1X

Secure port login

IEEE 802.1Q

VLAN tag

IEEE 802.1D

STP (Spanning Tree Protocol)

IEEE 802.1w

RSTP (Rapid Spanning Tree Protocol)

IEEE 802.1AX

LACP (Link Aggregation Control Protocol)

IEEE 802.1AE

MACsec (Media Access Control Security)

If you know where the network problem might be...

Use the Divide and Conquer troubleshooting approach.

If you have no clue where the network problem is...

Use the Top-to-Bottom or Bottom-to-Top troubleshooting approach.