Sdwan Application Aware Routing

[Mahendervyas35821]

Hello Community, 

I have a query about Sdwan AAR ( application aware routing ) .

I have a sdwan setup with controllers on premises and may setup looks fimilar to below detaisl . 

Branch --> MPLS Provider --> DC --> DC FW--> Internet . 

Between Branch and DC i have 2 MPLS links , assume color names MPLS and Private5 . 

I have a Business critical applications like salesforce and SFDC . 

I want to configure AAR in such a way that initially traffic should load-balance between both available transports and if any transport doesn't meet SLA perimeters then traffic should not pass from that transport but should continue from another available transport.

As per my communication with TAC they said we can make MPLS as a prefered path and private5 as a back , if i apply this then iam utilizing only one link and wasting another link . 

Just curious As sdwan was made for AAR and Load balancing for better performance and now passing a traffic from only one link , i don't think customer will be happy with this type of solution .

will be thankful if any solution for Load balancing with AAR as i mentioned above . 

The only requirement is traffic should pass from both links and should stop passing from any link if SLA not meeting.

[rmfalconer]

In your application policy, what happens if you select both MPLS and Private5 as the Preferred Color? I think as long as both transports satisfy the SLA, ECMP should happen.

[Kanan Huseynli]

Hi,

it is strange that Cisco tac says such an answer.

https://www.cisco.com/c/en/us/td/docs/routers/sdwan/configuration/policies/ios-xe-17/policies-book-xe/application-aware-routing.html

Look flow chart as well.

ECMP happens if you don't mentione preferred color. In this case, ALL TLOCs that are SLA compliant are available to send that traffic.

If one or more does not satisfies, then TLOC is removed from forwarding list.

Just configure SLA class, apply to the traffic without preferred color. Or you may have multiple (both mpls and private5) in preferred color, but it does not give advantage/ any effect in your case.

HTH,

[Mahendervyas35821]

Hi @Kanan Huseynli 

Thanks for your Valuable reply . 

Just configure SLA class, apply to the traffic without preferred color. Or you may have multiple (both mpls and private5) in preferred color, but it does not give advantage/ any effect in your case.

As you said if i add both color it does not give any advantage , what do you mean by this . 

Please explain.

[Kanan Huseynli]

Hi,

I just wanted to give a bit detailed info.

In your case you have 2 TLOCs (colors). If you choose preferred color option and add both colors, then router does ECMP over both.

If you don't do preferred color and simple put SLA Class, again ECMP over both happens.

So, no different in you case (two TLOCs).

Using preferred color with multiple colors is effective when you have ,for example, 4 colors and you note 2 preferred colors. In that case, it makes sense.

HTH,