What is the client's IT budget for the network design project?

Q: What is the client's IT budget for the network design project?

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The [IT budget] probably is the most important question [to ask clients], and not for reasons of greed or commission, but because it's about setting expectations. You don't want to be in an environment where someone wants a billion-dollar network for $50, but you also want to make sure their budget is in sync with their expectations. There are certain design patterns that fit different budgets.

For WANs, if they want to go on the cheap, [they can use] VPNs over the Internet to connect buildings. This is very inexpensive, but it's not very reliable or very manageable.

A little bit more expansive, but more reliable, is using a multiprotocol label switching (MPLS) provider. These providers can run your WAN for you -- they've run a global or regional WAN, and you're sort of renting a chunk of it. Some MPLS providers are more high-end -- they do less oversubscription (how have they allocated how much bandwidth is going to be used on a certain link). So if you have a [MPLS] link that's a 10-Gigabit link, have [they] sold 10 Gigabits of that capacity, or have [they] sold 100 Gigabits of that capacity and are hoping that nobody is going to use their full capacity at any one moment?

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And then there are custom solutions because some customers just have the need for dedicated links, either for security reasons or because they just need that much bandwidth. On the LAN side, there are also different design patterns that match different costs levels, like with a network where a single fault can take down the network or disrupt users versus N+1 designs.