Merge ../linus

[linux-drm-fsl-dcu.git] / Documentation / networking / bonding.txt

diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt
index afac780445cd19a9042a629fa32245d11806e610..de809e58092fa070caa7fac46c6cc9bbac12aed4 100644 (file)
--- a/Documentation/networking/bonding.txt
+++ b/Documentation/networking/bonding.txt
@@ -192,6 +192,17 @@ or, for backwards compatibility, the option value.  E.g.,
 arp_interval
 
        Specifies the ARP link monitoring frequency in milliseconds.
+
+       The ARP monitor works by periodically checking the slave
+       devices to determine whether they have sent or received
+       traffic recently (the precise criteria depends upon the
+       bonding mode, and the state of the slave).  Regular traffic is
+       generated via ARP probes issued for the addresses specified by
+       the arp_ip_target option.
+
+       This behavior can be modified by the arp_validate option,
+       below.
+
        If ARP monitoring is used in an etherchannel compatible mode
        (modes 0 and 2), the switch should be configured in a mode
        that evenly distributes packets across all links. If the
@@ -213,6 +224,54 @@ arp_ip_target
        maximum number of targets that can be specified is 16.  The
        default value is no IP addresses.
 
+arp_validate
+
+       Specifies whether or not ARP probes and replies should be
+       validated in the active-backup mode.  This causes the ARP
+       monitor to examine the incoming ARP requests and replies, and
+       only consider a slave to be up if it is receiving the
+       appropriate ARP traffic.
+
+       Possible values are:
+
+       none or 0
+
+               No validation is performed.  This is the default.
+
+       active or 1
+
+               Validation is performed only for the active slave.
+
+       backup or 2
+
+               Validation is performed only for backup slaves.
+
+       all or 3
+
+               Validation is performed for all slaves.
+
+       For the active slave, the validation checks ARP replies to
+       confirm that they were generated by an arp_ip_target.  Since
+       backup slaves do not typically receive these replies, the
+       validation performed for backup slaves is on the ARP request
+       sent out via the active slave.  It is possible that some
+       switch or network configurations may result in situations
+       wherein the backup slaves do not receive the ARP requests; in
+       such a situation, validation of backup slaves must be
+       disabled.
+
+       This option is useful in network configurations in which
+       multiple bonding hosts are concurrently issuing ARPs to one or
+       more targets beyond a common switch.  Should the link between
+       the switch and target fail (but not the switch itself), the
+       probe traffic generated by the multiple bonding instances will
+       fool the standard ARP monitor into considering the links as
+       still up.  Use of the arp_validate option can resolve this, as
+       the ARP monitor will only consider ARP requests and replies
+       associated with its own instance of bonding.
+
+       This option was added in bonding version 3.1.0.
+
 downdelay
 
        Specifies the time, in milliseconds, to wait before disabling
@@ -964,7 +1023,7 @@ Changing a Bond's Configuration
 files located in /sys/class/net/<bond name>/bonding
 
        The names of these files correspond directly with the command-
-line parameters described elsewhere in in this file, and, with the
+line parameters described elsewhere in this file, and, with the
 exception of arp_ip_target, they accept the same values.  To see the
 current setting, simply cat the appropriate file.