bonding: document the new _arp options for arp_validate
CC: Jay Vosburgh <fubar@us.ibm.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt
index 96b4ad8..a383c00 100644
--- a/Documentation/networking/bonding.txt
+++ b/Documentation/networking/bonding.txt
@@ -270,16 +270,15 @@
arp_validate
Specifies whether or not ARP probes and replies should be
- validated in any mode that supports arp monitoring. 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.
+ validated in any mode that supports arp monitoring, or whether
+ non-ARP traffic should be filtered (disregarded) for link
+ monitoring purposes.
Possible values are:
none or 0
- No validation is performed. This is the default.
+ No validation or filtering is performed.
active or 1
@@ -293,31 +292,68 @@
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.
+ filter or 4
- The validation of ARP requests on backup slaves is mainly
- helping bonding to decide which slaves are more likely to
- work in case of the active slave failure, it doesn't really
- guarantee that the backup slave will work if it's selected
- as the next active slave.
+ Filtering is applied to all slaves. No validation is
+ performed.
- 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.
+ filter_active or 5
+
+ Filtering is applied to all slaves, validation is performed
+ only for the active slave.
+
+ filter_backup or 6
+
+ Filtering is applied to all slaves, validation is performed
+ only for backup slaves.
+
+ Validation:
+
+ Enabling validation 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.
+
+ For an 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 broadcast 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.
+
+ The validation of ARP requests on backup slaves is mainly helping
+ bonding to decide which slaves are more likely to work in case of
+ the active slave failure, it doesn't really guarantee that the
+ backup slave will work if it's selected as the next active slave.
+
+ Validation 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
+ validation can resolve this, as the ARP monitor will only consider
+ ARP requests and replies associated with its own instance of
+ bonding.
+
+ Filtering:
+
+ Enabling filtering causes the ARP monitor to only use incoming ARP
+ packets for link availability purposes. Arriving packets that are
+ not ARPs are delivered normally, but do not count when determining
+ if a slave is available.
+
+ Filtering operates by only considering the reception of ARP
+ packets (any ARP packet, regardless of source or destination) when
+ determining if a slave has received traffic for link availability
+ purposes.
+
+ Filtering is useful in network configurations in which significant
+ levels of third party broadcast traffic would fool the standard
+ ARP monitor into considering the links as still up. Use of
+ filtering can resolve this, as only ARP traffic is considered for
+ link availability purposes.
This option was added in bonding version 3.1.0.