Designing networks always reminds me about traffic control, with a few adjustments:
- packets can only travel with constant speed from point A to point B.
- packets can not stand still on the freeway they have to buffer in city parking.
- Red lights are forbidden
- Roundabouts that will divert traffic with dynamic road signs (we call them routers).
- If you need to do a roundabout make sure it can handle the traffic
Now given these (and I probably missed a few), would you:
- Place a roundabout on the middle of 405 between Santa Monica and Highway 5?
- Have all traffic go to downtown LA before you go anywhere else?
- Have everybody go to work at 9 and come back at 5 (wait… we do that:))?
- Widen highway 405 over the Sepulveda pass (wait…we are doing that:))?
- Don’t use a top of rack switch for routing if what you need is a juniper MX80 or a MLX4e
So here is my point:
- Rsync via cron (e.g. start at 9 and come home at 5 is a bad idea), spread out the load over time.
- Distributed spine: fastest path between A and B and A and D is good without going over C.
- Widen network bandwidth in high traffic points (e.g. go 40 gig between 405 and Highway 5)
- Don’t do Layer 3 when all you need is simple Layer 2 (e.g. no roundabouts on 405).
- If you are going to use buffers (city parking), make sure you are not flowing over (e.g. use large buffers).
- Design your network for peak, although you took away the 9-5. Most people want to have lunch at work!