[ovs-git] Open vSwitch: vswitchd: Make the MAC entry aging time configurable. (branch-1.4)

dev at openvswitch.org dev at openvswitch.org
Wed Feb 1 23:13:01 UTC 2012


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The branch, branch-1.4 has been updated
       via  231ee9b7442e515bc654dee37806ee957f74afd7 (commit)
       via  349dba3bcbe2bc447c7b0999427df6c748e35c09 (commit)
      from  c5cd317a53fa4f29ab39ee364a5151f7b700ee8d (commit)

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- Log -----------------------------------------------------------------
commit 231ee9b7442e515bc654dee37806ee957f74afd7
Diffs: http://openvswitch.org/cgi-bin/gitweb.cgi?p=openvswitch;a=commitdiff;h=231ee9b7442e515bc654dee37806ee957f74afd7
Author: Ben Pfaff <blp at nicira.com>
		
vswitchd: Make the MAC entry aging time configurable.
		
NICS-11.
Signed-off-by: Ben Pfaff <blp at nicira.com>


commit 349dba3bcbe2bc447c7b0999427df6c748e35c09
Diffs: http://openvswitch.org/cgi-bin/gitweb.cgi?p=openvswitch;a=commitdiff;h=349dba3bcbe2bc447c7b0999427df6c748e35c09
Author: Ben Pfaff <blp at nicira.com>
		
mac-learning: Increase MAC learning timeout to 300 seconds.
		
When Cisco (and other?) routers are configured in high-availability modes,
they use two different MAC addresses.  The router uses MAC 1 only for ARP
replies.  The router uses MAC 2 for forwarding IP packets to end hosts.
When a MAC learning switch is attached to the router, therefore, it will
only learn the location of MAC 1 from ARP replies.  If the end host's ARP
cache refresh timer is longer than the switch's MAC learning timeout, then
packets to the router will be flooded from the MAC learning timeout until
the next ARP reply.

This commit fixes the problem by increasing the MAC learning timeout from
60 seconds to 300 seconds.  According to research by Sanjay Sane, this is
always sufficient, even with operating systems that use ARP timeouts
longer than 300 seconds (such as FreeBSD and Mac OS, which have 1200
seconds ARP timeouts)  because the routers that cause this problem send
unsolicited ARP replies every 180 seconds.

This issue arises in any situation where traffic between two hosts flows
only in one direction.  The explanation above describes only one special
case.

NICS-11.
Signed-off-by: Ben Pfaff <blp at nicira.com>


-----------------------------------------------------------------------

Summary of changes:
 NEWS                       |    6 ++++++
 lib/learning-switch.c      |    6 ++++--
 lib/mac-learning.c         |   41 ++++++++++++++++++++++++++++++++++-------
 lib/mac-learning.h         |   12 ++++++++----
 ofproto/ofproto-dpif.c     |   13 +++++++++++--
 ofproto/ofproto-provider.h |    4 ++++
 ofproto/ofproto.c          |   10 ++++++++++
 ofproto/ofproto.h          |    3 ++-
 vswitchd/bridge.c          |   17 +++++++++++++++++
 vswitchd/vswitch.xml       |   20 ++++++++++++++++++++
 10 files changed, 116 insertions(+), 16 deletions(-)


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