I did look into this a bit before. To be more specific: IPv6 CEF appears to be functioning normally for prefixes longer than 64-bit on my 720(s). I'm not seeing evidence of unexpected punting. The CPU utilization of the software process that would handle IPv6 being punted to software, "IPv6 Input", is at a steady %0.00 average (with spikes up to 0.02%). So there would seem to be at least one major platform that is OK. On Wed, Dec 28, 2011 at 12:51 PM, Ryan Malayter <malayter@gmail.com> wrote:
On Dec 28, 9:44 am, Ray Soucy <r...@maine.edu> wrote:
For what its worth I haven't stress tested it or anything, but I haven't seen any evidence on any of our RSP/SUP 720 boxes that would have caused me to think that routing and forwarding isn't being done in hardware, and we make liberal use of prefixes longer than 64 (including 126 for every link network). They might just be under capacity to the point that I haven't noticed, though. I have no problem getting muti-gigabit IPv6 throughput.
You can get >10GbE *throughput* from a Linux box doing all forwarding in software as well. That's easy when the packets are big and the routing tables are small, and the hash tables all fit in high-speed processor cache.
The general lack of deep information about how the switching and routing hardware really works for IPv6 is my main problem. It's not enough to make informed buying or design decisions. Unfortunately, I have over the course of my career learned that a "trust but verify" policy is required when managing vendors. Especially vendors that have a near-monopoly market position.
The problem, of course, is that verifying this sort of thing with realistic worst-case benchmarks requires some very expensive equipment and a lot of time, which is why the lack of solid information from vendors and 3rd-party testing labs is worrying.
Surely some engineers from the major switch/router vendors read the NANOG list. Anybody care to chime in with "we forward all IPv6 prefix lengths in hardware for these product families"?
-- Ray Soucy Epic Communications Specialist Phone: +1 (207) 561-3526 Networkmaine, a Unit of the University of Maine System http://www.networkmaine.net/