I started with SD-WAN end of 2019 when a customer asked to set with me for few days to explain Cisco SD-WAN.
I followed Cisco SD-WAN Operation and Deployment (ENSDW) course outline.
While I am preparing, I found all viptela components and terminology were really easy to understand.
The 4Vs in cisco viptela are similar to the three VeloCloud Components etc
But since I knew that my training could be change to a consultation session , I asked myself ,
WHY , WHY we are doing SD-WAN ?
And I found that the answer is also the same answer for another question which is
What is next?
What is next after implementing transport connections (colors) to connect my branches with HQ using MPLS , 4G …etc?
To answer that I decide to think like I am the customer and since nowadays, the majority of enterprise traffic flows to public clouds and the Internet, I found the following:
I need to see the connections between my HQ/ branches automated, smart and policy based with centralized management.
I need to have the capability to add more branches without touching or changing anything in my color
I need to have the capability to automate my QoS settings and make it change dynamically based in real time bandwidth monitoring
I need to have capability to communicate over my SD-WAN fabric with my cloud services such as office 365 & Salesforce.com (SaaS) or even communicate with branch that is completely exists in AWS (IaaS) .
Also how all of this will be secure and how security services layer can be added dynamically to all of it.
SD-WAN try to help us with these new requirements for security, application performance, cloud connectivity, WAN management, and operations
It fully integrates routing, security, centralized policy, and orchestration into large-scale networks.
It is multi-tenant, cloud-delivered, highly-automated, secure, scalable, and application-aware with rich analytics.
With Cisco SD-WAN Cloud OnRamp, the SD-WAN fabric continuously measures the performance of a designated application through all permissible paths from a branch (i.e. MPLS, Internet, and 4G LTE).
The Cisco SD-WAN fabric automatically makes real-time decisions to choose the best-performing path between the end users at a remote branch and the cloud application.
What all of the above doing with MPLS? The simple answer is nothing
MPLS is just one of many a underlay networks we can use to have our overlay SD-WAN fabric
I can say people who compare MPLS with SD-WAN are not really understand what is SD-WAN.
Also they skip the fact that MPLS is not only MPLS L3 VPN.
Anyway , replacement for MPLS as transport option could be a high speed Internet connection (if we can ensure privacy to it).
Another more realistic replacement option for MPLS could be SRv3 , specially when to come to MPLS TE.
I wrote this article as introduction to cisco SD-WAN:
Also Cisco SD-WAN Viptela Resources and prerequisites:
Yasser Ramzy Auda