Posted by: Eric Siegel
Software as a Service (SaaS) is tempting a lot of enterprises, but I worry that the service level agreements (SLAs) for these services may be incomplete.
It's important to define precisely what the service provider means by availability and performance. Is it measured inside the provider's server center? If so, then that's not particularly useful, unless your salesreps and other employees typically have their meetings there!
What you should want is a set of metrics to the locations where your staff does their work; e.g., inside your branch offices or on the road, across the Internet. Make the SaaS provider responsible for ensuring that communications is acceptable to the boundary of your office or to major Internet access points.
You can set up measurements at your branch office boundary router (to ensure that the provider isn't held responsible for problems inside the branch office network) and measure round-trip latency, availability, and possibly the home page download time for the SaaS provider from that point. (Coupled with a server-room measurement from the provider of the SaaS service, you will probably need only DNS resolution time to the SaaS site, availability of the SaaS servers, and round-trip TCP latency to the SaaS servers, unless the SaaS design is such that multiple server rooms are involved.)
Be sure that both you and the SaaS provider can see the metrics in real time and agree on the technology involved; the goal is to have the provider notice that the SLA metrics are in trouble and fix the underlying problem before a major outage or performance crisis occurs.
If your SLAs are being violated a lot of the time, then it's the service provider's responsibility to fix the communications between the SaaS server room and your branch offices. They may need to install a dedicated comms link, or a cache or WAN performance optimizer system, or a reworking of some of the SaaS software or tuning of the caching headers. But it's their problem, not yours, if you've written the SLA correctly.
And that extends to people on the road using the SaaS package. The SaaS provider can't be expected to handle every lousy last-mile comms link through a underpowered hotel firewall and a dial-up line made out of 50-year-old twisted pair. BUT the SaaS provider should, at least, provide decent performance to major nodes in geographic regions where you have a presence and on Internet service providers that your staff uses.
To keep track of over-the-Internet SaaS performance, you could set up a few monitoring facilities with short, uncongested links to the Internet service providers that your mobile staff use, or you could subscribe to a public service that already has those links and the credibility with service providers. (Examples are Neustar's Webmetrics GlobalWatch Ecosystem Management, which includes a specialty service for monitoring of major SaaS providers, as well as the standard Web transaction performance monitoring services such as Compuware's Gomez and Keynote Systems [where I used to work!] These vendors can also provide on-site monitoring appliances for your branch offices, to evaluate SaaS performance there.)
If performance is poor, the SaaS provider should have some serious talks with their Internet service provider, and possibly move to another provider or insist on better peering with the providers that you, their customer, use.
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