SDWAN Best Quality vs Lowest Cost

[HS08]

Someone can correct me if my understanding below is correct or not regarding sdwan best quality and lowest cost (SLA).

Best quality 

When use best quality the parameter used is only to select one from available below

Lowest Cost (SLA)

With this criteria then the parameter used is SLA target from each performance SLA?

[Atul_S]

Hi HS08,

Your understanding is correct.

For "Best Quality", SD-WAN selects the best link based on a single link-cost-factor parameter, such as latency, jitter, packet loss etc. The selection is made by comparing these factors to determine the best quality link for traffic forwarding. Whereas under "Lowest Cost" uses SLA targets to prioritize links based on performance SLA thresholds that prove the ability to meet these SLA criteria, ensuring that the traffic is routed through the most cost-effective path that still meets the defined performance standards.

[HS08]

For Lowest SLA the link will be failover if all enabled parameters (in my prev picture is 3) have value higher than threshold or even only one parameter then the link will be switched?

If we set packet loss 1% this mean the link will be switched if more than 1% or even ewual to 1% the link will be switched?

[Atul_S · Accepted solution]

Hi HS08,

Thanks for your reply. In the Lowest Cost strategy, a link will be considered for failover if any of the enabled SLA parameters exceed their defined thresholds. Hence, in your case, the link will be switched if it's above 1% and there won't be any change as long as it remains at 1 or below.

[fulapmu2]

Fortinet may not be as easy as other vendors , but building a vpn tunnel and routing over it isn't exactly complicated. You can follow fortinet guides or continue using the routing protocols and architecture you use today since fortigates are capable of handling almost all network technologies you throw at it. The SD-WAN feature makes it easy to combine those interfaces to have load-balancing, SLA monitoring, different routing path depending on the type of trafic,etc. on top of your network architecture without the need to think about asymmetric routing. For me it's the most robust way to build it as you know already how to troubleshoot your network and it's usually easier to troubleshoot than a blackbox that "does everything automagically". I hate Merakis for this, it just works that's true, but when it doesn't it isn't as easy to fix. If you don't have a good network, yes those blackboxes work great.