Hz so good wrote:
The high end routers and switches (Cisco or any other manufacturer) use custom ASICs. You aren't going to get much beyond marketing fluff terms unless you are working directly on them as these things are competitive advantages between manufacturers. They all know roughly what each other is doing anyway from getting hold of the other ones equipment, beating up on it in testing and reverse engineering, but the details are still secret.
I'm trying to get as many cisco certs as possible, and I'd imagine that have that info would help with me getting my CCNA Datacenter, since those switches tend to be ToR. Shame Cisco is trying to hold this close to it's vest, since I'm curious if any of those latency reducing techniques would be useful in other DC operations.
As someone else pointed out, you will never be exposed to the secret sauce that makes the ASICs so fast. You're left at the implementation level where most of it is common sense for someone who knows how a big switch works: no L3 routing on the switch, set QOS appropriately, no filtering, all ports at the same speed, etc. When you get down to micosecond latencys, it does help a little to stop and think about how the switch is architected. You don't want to cross line cards. Going from the top line card to the bottom line card in a large switch could add 5ns, just in physics. In fact, if you can stay within the same switching ASIC (usually a group of four ports), even better. You can get really carried away if you feel like it, but even in an high perfomance datacenter you are still only plugging things and twiddling some IOS settings. Unless you are doing HFT, nobody cares because the difference between 150us and 350us latency across a switch doesn't matter anywhere else.
You mentioned the freespace laser link in the beginning. As an aside, that laser link (when it is working) would be about 50% lower latency than a fibre optic link of the same distance and something like 30% lower latency than a copper link of the same distance. It can also be disrupted by a bird....