As enterprises seek to expand 5G/LTE or MPLS networks, they must
set SLAs. Inside of those SLAs, key performance indicators (KPIs) drive the
progression of the network. With the expansion of SD-WAN deployments, network
administrators need assurance that the KPIs of branch sites align with their
current infrastructure. Tracking the performance of how the applications
connect to their assigned virtual private network (VPN) and DSCP class enables the
service provider to validate the SLA performance of a potential problem and
resolve it swiftly.

Key KPIs Enterprise Identify for SD-WAN Visibility

Many SD-WAN vendors use actionable data, which provides visibility
of network KPIs from the SD-WAN devices by regulating features such as reachability,
fabric performance, transport interface distribution, and site-to-site VoIP
quality.

As SD-WAN vendors work to track KPIs from SD-WAN devices, each vendor must develop their own proprietary algorithm for SD-WAN to manage data transmission. Each algorithm must regulate how traffic is directed over a specific link or when to switch traffic from one link to another. Viptela, a well-known SD-WAN vendor, developed 22 cflowd IPFIX information elements to track root cause of SD-WAN performance. These information elements enable customers to verify whether the SD-WAN is working as they expect. KPIs should not be withheld from the customer, as evaluating the application performance is important when rerouting traffic. With SD-WAN being a new technology, questions will be raised on what caused rerouting. Furthermore, knowing the root cause for rerouting helps customers take a proactive approach to avoid rerouting in the near future, thus enabling customers to have deeper visibility and reduce the frequency of these events.

KPIs to manage SD-WAN routers

Using Scrutinizer for traffic monitoring and flow analytics gives you the full story of your network. As SD-WAN vendors work to extract IPFIX information elements from SD-WAN devices, it gives network administrators better traffic visibility and single a point of failure for SD-WAN exports. Viptela has identified key performance indicators which are effective in the management SD-WAN vEdge routers.  

x01: idle timeout

The Flow was terminated because it was considered to
be idle.

0x02: Active timeout

The flow was terminated for reporting purposes while
it was still active. For example, after the maximum lifetime of unreported
flows was reached.

0x03: End of Flow detected

The flow was terminated as the metering process
detected signals indicating the end of the Flow. For example, the TCP FIN flag.

0x04: Forced end

The flow was terminated because of some external
event. For example, a shutdown of the metering process initiated by a network
management application.

0x05: Lack of resources

The Flow was terminated because of a lack of resources available
to the Metering Process and/or the exporting process.

To find out a real reason why the flow was rerouted we need
additional values. Please check out the VoIP quality stats below.

0x06: Jitter

Flow rerouted due to excessive jitter in VoIP
transmissions

0x07: Packet Loss

Flow rerouted due to excessive packet loss in UDP
connections

0x08: Retransmits

Flow rerouted due to excessive TCP retransmits

0x09: RTT flow rerouted due to excessive TCP setup
times

The information elements documented by IANA clarifying why
something occurred to a flow are: forwardingStatus(89), flowEndReason(136),
firewallEvent(233)

Conclusion

As enterprise data migrates from private WAN to the cloud, it is
essential to have effective KPIs to manage complex hybrid networking environments.
Using current flow exports does not provide enough visibility
to investigate a link failure, but pointing your SD-WAN devices toward Scrutinizer
allows NetOPS to track events such as link failure, latency, and packet loss
enables. Finally, if you need lateral visibility at branch sites
or edge routers within your network, configure NetFlow and download Scrutinizer,
and become network-aware.

Elgin Robinson

Elgin Robinson

Elgin provides pre-sales support to the sales team at Plixer. Elgin comes from a technical support background, having years of experience doing everything from sales engineering to technical support. Some of his interests include spending quality time with his significant other, mentoring youth in the DFW area, playing bingo with the elderly, and staying fit with the local CrossFit and boot camps in his area.