Thread (18 messages) 18 messages, 5 authors, 2017-09-19

Re: [RFC net-next v2] bridge lwtunnel, VPLS & NVGRE

From: David Lamparter <hidden>
Date: 2017-08-22 12:06:10
Also in: bridge

On Tue, Aug 22, 2017 at 02:55:04PM +0300, Nikolay Aleksandrov wrote:
On 22/08/17 14:32, David Lamparter wrote:
quoted
On Tue, Aug 22, 2017 at 02:01:40PM +0300, Nikolay Aleksandrov wrote:
quoted
On 22/08/17 03:01, Stephen Hemminger wrote:
quoted
I know the bridge is an easy target to extend L2 forwarding, but it is not
the only option. Have you condidered building a new driver (like VXLAN does)
which does the forwarding you want. Having all features in one driver
makes for worse performance, and increased complexity.
+1

As I said before, a separate implementation will be much cleaner and will not affect
the bridge in any way, paying both performance and complexity price for something that
the majority of users will not be using isn't worth it.  In addition this creates a
silent dependency between the bridge and the fdb metadata dst users, it would be much
more preferable to be able to run them separately.
If there is any code that will need to be re-used by VPLS (or anyone else) figure out a way
to factor it out.
Could you tell me why this argument didn't apply to the bridge vlan
tunnel code?  It adds complexity to the bridge specifically for VXLAN
(and it does *not* transfer to VPLS or 802.11) and reduces performance

... by actually accessing the same metadata that this patchset does.
The separation is clean and does not add any dependencies, that code
is well isolated.  As for performance, the impact is minimal as it
adds a test for a port flag that is already in the cache at that
point.
Ah, ok, now this is useful input... I can add a BR_PORT_METADATA flag.
In fact it can be compiled-out entirely if you disable bridge vlan
support. The metadata you're referring to is not accessed if the port
flag is not set or vlan support is compiled out removing its impact
entirely.
Ok, I can probably adapt this patchset to do the same.
You can have a vxlan setup without bridge, no ?
You can run the VPLS code without a bridge too... behaviour will be the
same as with other ip tunnels when you set the destination to multicast
(packets get flooded.)


-David
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