Date: Mon, 19 Sep 2005 13:17:22 -0400 From: Charles Swiger <cswiger@mac.com> To: Daniel Pocock <daniel@lvdx.com> Cc: freebsd-isp@freebsd.org Subject: Re: FreeBSD, quagga (BGP) and 2950 VLANs Message-ID: <8AB0B562-974F-48EB-BCB4-B8491E7AEFF5@mac.com> In-Reply-To: <432EC4FF.4030706@lvdx.com> References: <432EC4FF.4030706@lvdx.com>
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On Sep 19, 2005, at 10:02 AM, Daniel Pocock wrote:
> I've been told that FreeBSD performs routing computations in linear
> time, even with large routing tables (such as from BGP), and that
> it is therefore superior to Linux for use as a border router. Is
> this so, and are there any specific documents I should review about
> the performance of FreeBSD routing?
I believe FreeBSD uses a radix lookup for the routing table which is O
(1); I don't know enough about the implementation in Linux to make
claims about one platform being superior.
> I've discovered that there is the 4.11 release and the 5.4
> release. Are there any compelling reasons why I should choose one
> of these over the other, for my intended application? The only
> application I will be running is quagga.
If you are setting up a new system, you should go with 5.4. 4.11 is
older and thus extremely well-tested by now, and might arguably be a
bit more reliable, but 5.4 has better support for ACPI and recent
hardware, as well as a significantly better SMP implementation.
> I'm planning to connect the FreeBSD server to a trunk port on a
> Cisco 2950 and put each interconnected IP provider into a separate
> VLAN. The documentation I've read so far suggests that FreeBSD is
> happy with VLANs - will this arrangement work and will it have any
> significant effect on performance?
This ought to work fine, but you might want to make sure your NICs
supports VLAN_MTU and VLAN_HWTAGGING options to help offload some of
the work:
bge0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
options=1a<TXCSUM,VLAN_MTU,VLAN_HWTAGGING>
"man 4 vlan" has a more complete discussion, including a list of NICs
which have this kind of hardware support. The Broadcom bge's and
Intel's em seem to work well.
--
-Chuck
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