SD WAN
SD WAN
SD-WAN (Software-Defined Wide Area Network) is a modern technology used to connect branch offices, remote users, cloud services, and data centers over a WAN (Wide Area Network).
SD-WAN uses software and centralized management to intelligently route traffic across multiple network connections such as:
Broadband Internet
MPLS
Fiber
4G/5G cellular
Satellite
Why Was SD-WAN Created?
Traditional WANs often relied on expensive MPLS circuits:
Plain Text
Branch Office
|
MPLS
|
Data Center
Show more lines
Problems:
❌ Expensive
❌ Difficult to scale
❌ Slow to deploy
❌ Limited cloud optimization
SD-WAN solves these problems by using multiple connection types and automatically selecting the best path.
How SD-WAN Works
Instead of manually configuring routes, SD-WAN continuously monitors network conditions:
Bandwidth
Latency
Packet loss
Jitter
It then chooses the best path for the traffic.
Plain Text
MPLS
|
Branch ----+---- Data Center
|
Broadband
|
5G
Show more lines
SD-WAN automatically selects the optimal connection.
Example
A branch office has:
Plain Text
1. MPLS
2. Fiber Internet
3. 5G Backup
Show more lines
Voice Call
Uses:
Plain Text
MPLS
Show more lines
because it has the lowest latency.
File Download
Uses:
Plain Text
Broadband Internet
Show more lines
because it has more bandwidth.
MPLS Failure
Automatically switches to:
Plain Text
5G Backup
Show more lines
without manual intervention.
Key Components
SD-WAN Edge Device
Located at branch offices.
Plain Text
Branch Office
|
SD-WAN Edge
Show more lines
Manages WAN connections and applies policies.
SD-WAN Controller
The centralized management system.
Administrators can:
Configure policies
Monitor performance
Manage all branch locations
from a single dashboard.
WAN Links
Can include:
Plain Text
MPLS
Broadband
Fiber
5G
Satellite
Show more lines
Application-Aware Routing
One of SD-WAN's biggest advantages.
It can identify applications and route them differently.
Example:
Application Preferred PathMicrosoft Teams MPLS
VoIP MPLS
Email Broadband
Software Updates Broadband
Video Streaming Broadband
SD-WAN vs MPLS
Feature MPLS SD-WANUses Labels Yes No
Cost High Lower
Uses Internet Usually No Yes
Centralized Management Limited Yes
Cloud Friendly Moderate Excellent
Automatic Path Selection Limited Yes
Multiple Links Limited Yes
Benefits of SD-WAN
✅ Lower WAN costs
✅ Better cloud performance
✅ Centralized management
✅ Automatic failover
✅ Improved application performance
✅ Supports remote offices
✅ Better visibility into network traffic
✅ Supports multiple WAN connections simultaneously
Automatic Failover Example
Normal Operation:
Plain Text
Branch
|
Fiber Internet
|
Data Center
``
Show more lines
Connection Fails:
Plain Text
Branch
|
5G Backup
|
Data Center
Show more lines
The switch can happen automatically with little or no interruption.
Common SD-WAN Vendors
Cisco SD-WAN (Viptela)
VMware VeloCloud
Fortinet Secure SD-WAN
Palo Alto Prisma SD-WAN
Aruba EdgeConnect
Versa Networks
SD-WAN and Security
Many SD-WAN solutions include:
VPN encryption
Firewalls
URL filtering
Intrusion prevention
Zero Trust integration
This is often called:
Plain Text
Secure SD-WAN
Show more lines
Real-World Example
A company has offices in:
Plain Text
Chicago
Dallas
New York
Los Angeles
Show more lines
Instead of buying expensive MPLS circuits for every office, they use:
Plain Text
Broadband Internet
+
SD-WAN
+
VPN Encryption
``
Show more lines
The offices stay securely connected at a lower cost.
Network+ Exam Tips
Remember
SD-WAN = Software-Defined WAN
The key idea is:
Plain Text
Software controls WAN traffic.
Show more lines
Key Features
Centralized management
Application-aware routing
Automatic failover
Multiple WAN links
Cloud optimization
MPLS vs SD-WAN
Plain Text
MPLS = Label-Based WAN
SD-WAN = Software-Controlled WAN
Show more lines
Quick Memory Trick
Plain Text
MPLS = Expensive Private Highway
SD-WAN = Smart GPS Navigation System
``
Show more lines
It constantly evaluates conditions and chooses the best route.
Simple Definition
SD-WAN (Software-Defined Wide Area Network) is a WAN technology that uses centralized software control to intelligently route network traffic across multiple connections such as MPLS, broadband Internet, and cellular networks, improving performance, reliability, and cost efficiency.
 "image title")
Subscribe to our newsletter
Sign up with your email address to receive news and updates.