[167728] in North American Network Operators' Group
Re: Mikrotik Cloud Core Router and BGP real life experiences?
daemon@ATHENA.MIT.EDU (Andre Tomt)
Fri Dec 27 15:37:12 2013
Date: Fri, 27 Dec 2013 21:36:57 +0100
From: Andre Tomt <andre-nanog@tomt.net>
To: nanog@nanog.org
In-Reply-To: <52BDAA34.7060002@shankland.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
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.
