Network Devices

What is a router?

A Layer 3 device that forwards packets between different networks using IP addresses.

What address does a router use to make forwarding decisions?

IP address

What OSI layer does a router operate at?

Layer 3 (Network)

What is router redundancy?

A backup router automatically takes over if the primary router fails.

What is clustering?

Multiple servers or devices working together as one system for higher performance and availability.

What is a Layer 3 switch?

A switch that combines Layer 2 switching with Layer 3 routing.

Which OSI layers does a Layer 3 switch operate at?

Layers 2 and 3

What is inter-VLAN routing?

Routing traffic between different VLANs (subnets).

What address does a Layer 3 switch use for routing?

IP address

What address does a Layer 3 switch use for switching?

MAC address

What is the purpose of a switch?

Connects devices within a LAN and forwards frames using MAC addresses.

What OSI layer does a switch operate at?

Layer 2

What address does a switch use?

MAC address

What is an ASIC?

A specialized chip that allows switches to forward traffic at very high speeds.

What does PoE stand for?

Power over Ethernet

What is PoE?

Technology that delivers both data and electrical power over one Ethernet cable.

Name three common PoE devices.

• IP cameras

• VoIP phones

• Wireless access points

What is a firewall?

A device or software that filters network traffic between trusted and untrusted networks.

What can firewalls filter?

• Source IP

• Destination IP

• Ports

• Protocols

What does a firewall log?

Network activity and blocked/allowed traffic.

What is an in-band security device?

A device that sits directly in the traffic path and can block traffic.

What is a Next-Generation Firewall (NGFW)?

A firewall that performs Deep Packet Inspection (DPI) and identifies application-level threats.

What is Deep Packet Inspection (DPI)?

Examining packet contents—not just headers—to detect malware and policy violations.

Which devices commonly perform NAT?

Routers (sometimes Layer 3 switches)

What is an IDS?

Intrusion Detection System

What does an IDS do?

Monitors traffic and alerts administrators without blocking traffic.

Is an IDS in-band or out-of-band?

Out-of-band

What is a TAP or SPAN port used for?

Sending a copy of network traffic to an IDS.

What is an IPS (stand for)?

Intrusion Prevention System

What does an IPS do?

Detects and actively blocks malicious traffic.

Which is passive: IDS or IPS?

IDS

Which is active: IDS or IPS?

IPS

Can IDS and IPS generate false positives?

Yes

What is load balancing?

Distributing network traffic across multiple servers.

Why use load balancing?

• Improves performance

• Reduces latency

• Prevents server overload

• Increases availability

What is fault tolerance?

The ability to continue operating after a failure.

What is a single point of failure?

A single component whose failure brings down the system.

What is SSL offloading (SSL termination)?

A load balancer decrypts HTTPS traffic before sending HTTP to backend servers.

Why use SSL offloading?

Reduces CPU load on web servers.

What is caching?

Storing frequently used data closer to users for faster access.

What are the benefits of caching?

• Faster responses

• Reduced bandwidth

• Lower server load

What is browser caching?

Stores web content locally on a user's device.

What is a proxy cache?

A shared cache used by multiple users.

What is a CDN?

A global network of servers that delivers content from the closest location.

What is QoS?

Prioritizing important network traffic over less critical traffic.

Which traffic is commonly prioritized by QoS?

• VoIP

• Video conferencing

• Streaming

What is a proxy server?

A server that acts as an intermediary between clients and the internet.

Why use a proxy server?

• Hide client IP addresses

• Filter websites

• Improve security

• Cache content

What is a transparent proxy?

A proxy that intercepts traffic automatically without client configuration.

What is a NAS?

Network Attached Storage

What type of storage does a NAS provide?

File-level storage

How does a NAS appear to users?

As a shared network folder.

What is a SAN?

Storage Area Network

What type of storage does a SAN provide?

Block-level storage

How does a SAN appear to servers?

Like a local hard drive.

What protocols can a SAN use?

• Fibre Channel (FC)

• iSCSI

• FCoE

What is a wireless access point (AP)?

A device that connects wireless clients to a wired network.

What OSI layer does an access point operate at?

Layer 2

What does an access point broadcast?

A Wi-Fi signal (SSID)

What is a Wireless LAN Controller?

A device that centrally manages multiple wireless access points.

What tasks does a WLC perform?

• Security policies

• SSID management

• Roaming

• Channel management

• Power management

Centrally manages multiple APs

WLC

Connects wireless devices to the wired network

Access Point