Big routers also mean they're a lot more expensive. You have to squeeze more life out of them because they cost you hundreds of thousands of dollars. You run them longer than you really should.
If you run more, smaller, $20k or $30k routers, you'll replace them on a more reasonable cycle. ----- Mike Hammett Intelligent Computing Solutions Midwest Internet Exchange The Brothers WISP ----- Original Message ----- From: adamv0...@netconsultings.com To: nanog@nanog.org Sent: Wednesday, June 19, 2019 3:22:45 PM Subject: few big monolithic PEs vs many small PEs Hi folks, Recently I ran into a peculiar situation where we had to cap couple of PE even though merely a half of the rather big chassis was populated with cards, reason being that the central RE/RP was not able to cope with the combined number of routes/vrfs/bgp sessions/etc.. So this made me think about the best strategy in building out SP-Edge nowadays (yes I'm aware of the centralize/decentralize pendulum swinging every couple of years). The conclusion I came to was that *currently the best approach would be to use several medium to small(fixed) PEs to replace a big monolithic chasses based system. So what I was thinking is, Yes it will cost a bit more (router is more expensive than a LC) Will end up with more prefixes in IGP, more BGP sessions etc.. -don't care. But the benefits are less eggs in one basket, simplified and hence faster testing in case of specialized PEs and obviously better RP CPU/MEM to port ratio. Am I missing anything please? *currently, Yes some old chassis systems or even multi-chassis systems used to support additional RPs and offloading some of the processes (e.g. BGP onto those) -problem is these are custom hacks and still a single OS which needs rebooting LC/ASICs when being upgraded -so the problem of too many eggs in one basket still exists (yes cisco NCS6k and recent ASR9k lightspeed LCs are an exception) And yes there is the "node-slicing" approach from Juniper where one can offload CP onto multiple x86 servers and assign LCs to each server (virtual node) - which would solve my chassis full problem -but honestly how many of you are running such setup? Exactly. And that's why I'd be hesitant to deploy this solution in production just yet. I don't know of any other vendor solution like this one, but who knows maybe in 5 years this is going to be the new standard. Anyways I need a solution/strategy for the next 3-5 years. Would like to hear what are your thoughts on this conundrum. adam netconsultings.com ::carrier-class solutions for the telecommunications industry::
