Why aren't more people using Cisco's IP SLA?

Q & A with Josh Stephens - VP and Head Geek of network management software vendor, SolarWinds.

Cisco IP SLA has been embedded in most Cisco switches and routers for the past decade. Many network admins and managers are aware of it, but may find it difficult or impossible to use. The below Q & A with Josh Stephens - VP and Head Geek of network management software vendor - SolarWinds, talks about Cisco's IP SLA and new software that according to Solarwinds makes IP SLA easy to use: 1. Why aren’t more people using Cisco's IP SLA and what common questions do you often hear about it?

Josh Stephens: Cisco IP SLA technology has been available on almost all business-class Cisco routers and switches for quite some time. That means that most people already have IP SLA technology in their network environment. The challenge has really been around how to best access and use IP SLA. So there are a couple of key reasons that more people haven’t adopted IP SLA. First, IP SLA operations have traditionally required the use of CLIs (command line interfaces) to configure and maintain – which is just difficult and overly time-consuming. Additionally, native IP SLA data results are hard to use and understand, particularly across multiple devices and network protocols. We designed Orion IP SLA Manager to make IP SLA more accessible and usable day-to-day by addressing these two issues. The most common questions we hear about Cisco IP SLA are which devices support it and how does it differ from NetFlow.

WAN Performance Dashboard 2. What does IP SLA monitoring get you that NetFlow doesn’t and does it replace NetFlow?

Josh Stephens: IP SLA doesn’t replace NetFlow- they’re complementary. Both technologies are embedded in Cisco IOS and are effectively "free" to network engineers. But, there are different use cases for each (see more in my "What is IP SLA?" tutorial). NetFlow is a "passive" technology that’s used to analyze traffic that exists on the network and to provide statistics on that traffic. IP SLA is more active and used to generate and analyze test traffic on the network. Used together, the technologies can give network management teams a more comprehensive perspective on network performance. While NetFlow is valuable for helping you understand and analyze the traffic on the network, IP SLA gives you visibility into actual network performance – specific to the applications that you care most about. Think of it this way. Your network is like a super highway. NetFlow sits at every intersection and tells you how many vehicles of each type are on the road and which direction they’re going. IP SLA allows you to send out your own drivers, in the types of cars that you choose, to tell you drive time along all of the available paths. Leveraging both of these technologies together is the sweet spot that you want to get to.

3. How does your new software, Orion IP SLA Manager, work with IP SLA to tackle some of the usability issues?

Josh Stephens: SolarWinds Orion IP SLA Manager was designed to make it much easier for network teams to deploy and use Cisco IP SLA technology. It automates the configuration and management of the IP SLA operations and pulls the data that is generated by IP SLA into an easy- to-use and understand web interface. Network teams can then use the data for performance analysis, alerting, and even within topology maps to display site-to-site network performance.

Broad IP SLA Operation Support 4. Why do you think it has taken so long to make IP SLA more user-friendly?

Josh Stephens: I think that most network management companies forget that a network engineer’s most valuable asset is time. While IT pros are certainly capable of doing this all by hand, they simply don’t have the spare cycles with everything else they’re managing. And while IP SLA, like its cousin NetFlow, is a really helpful and productive technology, it isn’t one of those BIG ideas that a lot of companies like to focus their product development on. We heard from a number of our customers that the ability to easily deploy and use IP SLA would improve their day-to-day work experience, so it became a priority for us to figure out how to make it work in the real world. Our relationship with Cisco allowed us to get a clear understanding of the available features within the technology, which gave us even better perspective on how to make IP SLA more usable.

5. What applications are driving more interest in IP SLA?

Josh Stephens: That list gets longer every day. Latency-sensitive and loss-intolerant applications like Voice and Video over IP are certainly driving a need for greater visibility into network performance. Additionally, SaaS and cloud-based services and applications, along with the adoption of MPLS and fully-meshed networks, have made understanding network performance on a per site, per path basis critical.

Advanced VoIP Monitoring The IP SLA operations currently supported by Orion IP SLA Manager include:

DHCP – Measure the round-trip time to retrieve an IP address
DNS – Measure the DNS look-up time (time to request and receive a reply)
FTP – Measure the round-trip time to transfer a file
HTTP – Measure the round-trip time to access a web page
ICMP Echo – Measure round-trip delay
TCP Connect – Measure connection time, which is useful for application and server monitoring
UDP Echo – Measure response times between IP SLA nodes using IP
UDP Jitter – Measure round-trip delay, one-way delay, one-way jitter, and one-way packet loss
VoIP UDP Jitter – Measure VoIP call path metrics

6. What’s the process for configuring IP SLA operations on a router?

Josh Stephens: By hand? Well, you’d have to either telnet or SSH to the router and then begin configuring each operation for each path individually. Like I mentioned, it can be a time-consuming and painful process.

Orion IP SLA Manager gives users a simple wizard that identifies which devices on the network support IP SLA and automatically sets up the desired operations: Automatic IP SLA Setup 7. What’s the performance impact of enabling IP SLA on devices?

Josh Stephens: In most cases, there is no noticeable impact on performance. It is possible to add so many operations that you could impact performance on some of the smaller routers, but it’s hard to imagine a scenario that would require adding that many. There are some great best practices and load calculators available at http://cisco.com/go/ipsla. If you’re concerned about performance, I would recommend going there and reading more. That said, the simplest way to ensure that you’re not negatively impacting device performance is to monitor the devices with a performance monitor, benchmark the performance before enabling IP SLA, and then continue to monitor as you add additional operations over time.

8. Any suggestions on how people who are not using IP SLA can get up and running?

Josh Stephens: One of the best ways to get started is to download a free tool that will help you familiarize yourself with the technology. We offer free tools for both NetFlow (SolarWinds Free Real-time NetFlow Analyzer; SolarWinds Free NetFlow Configurator) and IP SLA (SolarWinds Free IP SLA Monitor). And of course, for folks who just want to jump in… the free trials for Orion NPM and Orion IP SLA Manager are both available on the SolarWinds website. Select more Free Cisco Tools at BradReese.Com

SolarWinds Free IP SLA Monitor Related stories: Cisco voice monitoring tool updated by SolarWinds How to setup Cisco IP SLA jitter monitors How to setup a Cisco IP SLA TCP connect operation Are you taking advantage of NetFlow and IP SLA?


What's your take, why do you think more people aren't using Cisco's IP SLA?

BradReese.Com Cisco Refurbished - Services that protect, maintain and optimize Cisco hardware Contact: Brad Reese | Twitter: http://twitter.com/BradReese

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