From: Veaceslav Falico Date: Tue, 18 Feb 2014 06:48:41 +0000 (+0100) Subject: bonding: document the new _arp options for arp_validate X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=52f65ef33b3c99e7151ddb065988bb0b556e315e;p=linux-beck.git bonding: document the new _arp options for arp_validate CC: Jay Vosburgh CC: Andy Gospodarek Signed-off-by: Veaceslav Falico Signed-off-by: David S. Miller --- diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt index 96b4ad89cf25..a383c00392d0 100644 --- a/Documentation/networking/bonding.txt +++ b/Documentation/networking/bonding.txt @@ -270,16 +270,15 @@ arp_ip_target 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 @@ arp_validate 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. - - 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. - - 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 or 4 + + Filtering is applied to all slaves. No validation is + performed. + + 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.