nanog mailing list archives

Re: Mikrotik Cloud Core Router and BGP real life experiences?


From: Andre Tomt <andre-nanog () tomt net>
Date: Fri, 27 Dec 2013 21:36:57 +0100

On 27. des. 2013 17:26, Jim Shankland wrote:
<snip>
Routing table size was completely not an issue in our environment; we
were looking at a number of concurrent flows in the high-5 to
low-6-digit range, and since Linux uses a route cache, it was that
number, rather than the number of full tables we carried, that was
important.
<snip>

FYI, Linux no longer has a routing cache, so any performance numbers with the cache in place is void on modern kernels. It was deemed too fragile, handled mixed traffic badly, and was way easy to DoS. It wasnt simply just ripped out of course, the full lookups was made way faster and a bunch of scalability issues got plugged in the process.

All in all, in PPS, Linux should now handle mixed traffic much better, but less diverse traffic patterns might be a little slower than before. However, all in all, much more consistent and predictable.

Not everything is peachy though, there are still some cases that sucked last I checked. Running tons of tunnels beeing one. Multicast rx was severely gimped for a while after the removal, but that got fixed.


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