Application – Aware Routing Overview

Application – Aware Routing Overview

Posted on Jan 27, 2020 (0)

Application - Aware Routing Overview

Application aware routing is method by which it tracks the network performance and path characteristics of data plane tunnel between vEdge routers. These characteristics are packet loss, Latency, jitter, load, cost, Bandwidth of link etc.

Following are some benefits which application aware routing Provides:

  • Reduces Network Cost, data traffic can be load balanced
  • Increase in application performance without WAN upgrades
  • Real time Network and Path performance analysis reduces Network performance
  • Meet SLA for application Performance

Each vEdge router supports 8 TLOC which means it can connect to eight different WAN provider.

Application-Aware Routing Components:

There are three components of Application Aware Routing discussed below:

Identification: Identify the Application to meet specific SLA, Create the Centralized policy based on 6 tuple, and configure it on vSmart controller which further passes its decision to vEdge router.

Monitoring & Measuring: By BFD packets, Viptela actively monitors data traffic on tunnels between vEdge router and periodically measures tunnel performance with help of latency, jitter, and traffic loss, one-way and round trip time of traffic travelling in tunnel.

Mapping Application traffic to specific tunnel: Based on Monitoring and Measuring results, it maps the application data traffic to appropriate tunnel. This tunnel mapping is done based on teo criteria:

  • Best path criteria, measured from path characteristics
  • Constraints specified in policy specific to that application

Classification of tunnels in to SLA Class:

There are three parts though which any tunnel is classified in to one or more SLA class:

Measure Loss , Latency and Jitter: As soon as tunnel is established for data plane , BFD session automatically starts and these BFD session monitors the health and liveness of tunnel by sending hello packet periodically to detect weather link is operational or not. By BFD hello packets it also measure loss, Latency, jitter on links.

BFD Hello packet timer by default: 1 Sec

Calculate Average loss, Latency and Jitter: With the help of BFD, It pools all the tunnel to collect the packet latency, loss, jitter, and other statistics and then calculates Average of each parameters for each tunnel and then further calculates or recalculates the tunnel SLA, however Each poll interval is called as bucket and poll interval is about 10 minutes with BFD hello seconds is of 1 minutes.

The loss, latency and jitter information for each poll is preserved for six poll intervals and as soon as seventh poll interval is done, the earliest poll statistics is removed. 

Determine SLA classification: the information received by poll interval is used by Application-Aware routing function to determine the SLA classification for each tunnel. By default total 6 times the poll interval statistics are calculated that means loss, jitter , latency information is collected over an hour and then based on its average calculation , SLA classification of each tunnel is  determined.

The multiplier is user-configurable (with the bfd app-route multiplier command).

Based on the measurement and calculation of tunnel loss and latency, each tunnel may satisfy one or more user configured SLA classes



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