Logic behind Application aware routing- Cisco SDWAN

There are lot of terms people are talking about in next generation networks and one of the most important talks is Application aware routing. So from where this term came through and what does it means ?

Let's talk about Cisco SDWAN solution which provides the ability to use multiple transports in active-active state and intelligent to change the path accordingly whenever application faces issue.

What is the logic behind Application aware routing ?
App-aware routing leverages the following logic:

• Measure loss, jitter, latency parameters on all active tunnels.
• Centralize policy can be defined in order to measure SLA of the application
• Whichever path meets the SLA criteria which is used to steers application traffic. 

Fig 1.1- Cisco SDWAN APP Aware routing

From the above statement, let us suppose we have three different paths from source to destination.

• Path 1 : 10 ms, 0% loss, 5 ms jitter
• Path 2: 200 ms, 3% loss, 10 ms jitter
• Path 3: 140 ms, 1% loss, 10 ms jitter.

First path will be the best path as latency is 10ms and has no losses in the path with minimum of 5 % of jitter while Path 2 may be taken as worst path as per the SLA with 200ms latency and 3% loss and 10 ms jitter. You can use all these paths based on the critical applications from the best path and other from other paths which helps to use all paths and also the load balancing.

You can set the various parameters of application to be in SLA like the values of Latency, Jitter and losses. Like APP 1 which is most critical application in your environment you can put the SLA parameters like 

• Latency < 150ms
• Loss < 2%
• Jitter < 10 ms

So setting these parameters will automatically switched the path on SLA meets and you need not to be worried about if one path is performing low. 

Note : All these path using IP SEC tunnels from source to destination in order to reach to destination, so all these are highly secured for your data traffic.