Author Archives: Russ

Responding to Readers: Questions on Microloops

Two different readers, in two different forums, asked me some excellent questions about some older posts on mircoloops. Unfortunately I didn’t take down the names or forums when I noted the questions, but you know who you are! For this discussion, use the network show below.

In this network, assume all link costs are one, and the destination is the 100::/64 Ipv6 address connected to A at the top. To review, a microloop will form in this network when the A->B link fails:

  1. B will learn about the link failure
  2. B will send an updated router LSP or LSA towards D, with the A->B link removed
  3. At about the same time, B will recalculate its best path to 100::/64, so its routing and forwarding tables now point towards D as the best path
  4. D, in the meantime, receives the updated information, runs SPF, and installs the new routing information into its forwarding table, with the new path pointing towards E

Between the third and fourth steps, B will be using D as its best path, while D is using B as its best path. Hence the microloop. The first question about microloops was—

Would BFD help prevent the microloop (or Continue reading

Reaction: Billing by the Hour

A very common mistake I see among engineers of all stripes is a failure to fully appreciate the value of time—both what it is worth, and how to make your time more valuable.

What I normally see is something like this—I should be making $x/hour, because I have this specific experience, or that specific skill set. This focus on hourly pay, however, is actually counter productive. For instance, I recently ran across an article in a publication for graphic designers and illustrators (a world I have followed since I lived it in many years ago)—

Billing by the hour is the most popular pricing method across the world in most industries. Of course, there are many web designers/developers out there who make a great living by using the hourly billing method, but in my opinion, value-based billing is far better than hourly billing. —Kyle Prinsloo @Web Designer Depot

To begin, what does Kyle mean when he says to “bill by value” rather than billing by the hour? Once, when I went into a lawyers office, I noticed he had a sign on the wall that said, “Lawyers don’t charge by the bullet.” The point the lawyer was making Continue reading