In this chapter, we’ll look at technical issues involving entities outside your organization that you need to consider if you hope to offer a reliable web service.
The most powerful technique for providing a reliable service is redundancy: using multiple systems, Internet connections, routes, web servers, and locations to protect your services from failure. Let’s look at what can happen if you don’t provide sufficient redundancy.
It was Monday, July 10, and all of Martha’s Vineyard was full of vacation cheer. But for Simson Garfinkel, who had spent the weekend on the Massachusetts island, things were not so good. At 9:30 a.m., Simson was in the middle of downloading his email when suddenly IP connectivity between his house on Martha’s Vineyard and his house on the mainland was interrupted. No amount of pinging, traceroutes, or praying, for that matter, would make it come back.
What had happened to the vaunted reliability of the Walden network that we described in Chapter 2? In a word, it was gone. The Walden network had been decommissioned on June 30, when Simson moved from Cambridge to Belmont. Because Belmont’s telephone central office was wired for DSL, Simson was able to move his Megapath Networks DSL line, but Belmont’s cable plant had not been upgraded for data, so he had to leave his cable modem behind. So long, redundancy! On the plus side, with the money that Simson saved ...