Network Architecture Flashcards

What is Network Architecture?

The design, organization, and structure of a network.

What are the three layers of the Three-Tier Architecture?

Core Layer • Distribution Layer • Access Layer

What is the Core Layer?

The high-speed backbone of the network that moves traffic quickly between network sections. • 🧠 Core = Fast Highway

What are the responsibilities of the Core Layer?

High-speed forwarding • Connects network sections • High availability • Minimal processing

Does the Core Layer focus on security and filtering?

❌ No — the Core Layer focuses on speed and reliability.

What is the Distribution Layer?

The layer between Core and Access that controls traffic and applies policies. • 🧠 Distribution = Traffic Cop

What are the responsibilities of the Distribution Layer?

Routing • Inter-VLAN Routing • ACLs • Security Policies • QoS • Route Filtering

Which layer performs routing?

✅ Distribution Layer

Which layer performs Inter-VLAN Routing?

✅ Distribution Layer

What are ACLs?

Access Control Lists — rules that allow or deny network traffic.

What is the Access Layer?

The layer where users and devices connect to the network. • 🧠 Access = Front Door

What devices connect to the Access Layer?

PCs • Laptops • Printers • IP Phones • Cameras • Wireless Access Points

Which layer connects end devices?

✅ Access Layer

What is the normal traffic flow in a Three-Tier Network?

PC → Access → Distribution → Core

What is Spine-Leaf Architecture?

A modern architecture used in data centers.

How many layers does Spine-Leaf Architecture have?

2 Layers: • Spine • Leaf

What do Spine Switches do?

Provide high-speed connections between Leaf switches.

What do Leaf Switches connect to?

Servers • Storage • Virtual Machines • End Devices

What connects to servers in a Spine-Leaf network?

✅ Leaf Switches

What connects to Leaf switches?

✅ Spine Switches

What does every Leaf switch connect to?

✅ Every Spine switch

Why is Spine-Leaf popular in data centers?

Because it provides: • Low latency • High bandwidth • Redundancy • Easy scalability

Memory Trick for Spine-Leaf

🧠 Every Leaf knows every Spine

What is North-South Traffic?

Traffic entering or leaving the network.

Examples of North-South Traffic

Internet Browsing • Email • File Downloads • Internet Access

Memory Trick for North-South Traffic

🧠 Up & Down = Outside

What is East-West Traffic?

Traffic that stays inside the network.

Examples of East-West Traffic

Server → Server • VM → VM • Database → Application Server

Memory Trick for East-West Traffic

🧠 Side to Side = Inside

Which traffic type is common in data centers?

✅ East-West Traffic

What is SDN?

Software-Defined Networking — a network managed through centralized software.

What does SDN separate?

Control Plane • Data Plane

What is the biggest benefit of SDN?

Centralized Management

Why do companies use SDN?

Easier Automation • Faster Deployment • Centralized Control • Simpler Configuration

Memory Trick for SDN

🧠 One Dashboard Controls Everything

What is the Control Plane?

The part of a network device that makes decisions.

What does the Control Plane do?

Learns Routes • Runs Routing Protocols • Builds Routing Tables • Decides Packet Paths

Memory Trick for Control Plane

🧠 The Brain

Does the Control Plane move packets?

❌ No — it makes decisions.

What is the Data Plane?

The part of a network device that forwards packets.

What does the Data Plane do?

Moves Packets • Uses Forwarding Tables • Delivers Traffic

Memory Trick for Data Plane

💪 The Muscles

Does the Data Plane make routing decisions?

❌ No — the Control Plane makes decisions.

What is a Collapsed Core?

A design that combines the Core Layer and Distribution Layer into one device.

Which layers are combined in a Collapsed Core?

✅ Core + Distribution

Where is a Collapsed Core commonly used?

Small Businesses • Branch Offices • Small Campuses

Benefits of a Collapsed Core

Lower Cost • Simpler Management • Fewer Devices

What is Inter-VLAN Routing?

The process of allowing devices in different VLANs to communicate.

Can VLAN 10 communicate directly with VLAN 20?

❌ No — different VLANs are separate networks.

What device is required for Inter-VLAN Routing?

✅ Router or Layer 3 Switch

What happens during Inter-VLAN Routing?

Traffic goes to a Router / Layer 3 Switch, which forwards it to the destination VLAN.

Exam Trap: Which layer performs routing?

✅ Distribution Layer • ❌ Not Access Layer

Exam Trap: Which switch connects directly to servers?

✅ Leaf Switches • ❌ Not Spine Switches

Exam Trap: Is North-South traffic Server-to-Server traffic?

❌ No • North-South = Entering/Leaving the network • East-West = Internal traffic

Exam Trap: Does SDN forward packets?

❌ No • SDN manages the network. • The Data Plane forwards packets.