bonding: alternate agg selection policies for 802.3ad

	This patch implements alternative aggregator selection policies
for 802.3ad.  The existing policy, now termed "stable," selects the active
aggregator by greatest bandwidth, and only reselects a new aggregator
if the active aggregator is entirely disabled (no more ports or all ports
down).

	This patch adds two new policies: bandwidth and count, selecting
the active aggregator by total bandwidth (like the stable policy) or by
the number of ports in the aggregator, respectively.  These two policies
also differ from the stable policy in that they will reselect the active
aggregator when availability-related changes occur in the bond (e.g.,
link state change).

	This permits "gang failover" within 802.3ad, allowing redundant
aggregators along parallel paths to always maintain the "best" aggregator
as the active aggregator (rather than having to wait for the active to
entirely fail).

	This patch also updates the driver version to 3.5.0.

Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 42 insertions, 0 deletions

diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt
index 3f4d0fae708..5ede7473b42 100644
--- a/Documentation/networking/bonding.txt
+++ b/Documentation/networking/bonding.txt
@@ -194,6 +194,48 @@ or, for backwards compatibility, the option value.  E.g.,
 
 	The parameters are as follows:
 
+ad_select
+
+	Specifies the 802.3ad aggregation selection logic to use.  The
+	possible values and their effects are:
+
+	stable or 0
+
+		The active aggregator is chosen by largest aggregate
+		bandwidth.
+
+		Reselection of the active aggregator occurs only when all
+		slaves of the active aggregator are down or the active
+		aggregator has no slaves.
+
+		This is the default value.
+
+	bandwidth or 1
+
+		The active aggregator is chosen by largest aggregate
+		bandwidth.  Reselection occurs if:
+
+		- A slave is added to or removed from the bond
+
+		- Any slave's link state changes
+
+		- Any slave's 802.3ad association state changes
+
+		- The bond's adminstrative state changes to up
+
+	count or 2
+
+		The active aggregator is chosen by the largest number of
+		ports (slaves).  Reselection occurs as described under the
+		"bandwidth" setting, above.
+
+	The bandwidth and count selection policies permit failover of
+	802.3ad aggregations when partial failure of the active aggregator
+	occurs.  This keeps the aggregator with the highest availability
+	(either in bandwidth or in number of ports) active at all times.
+
+	This option was added in bonding version 3.4.0.
+
 arp_interval
 
 	Specifies the ARP link monitoring frequency in milliseconds.