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author | Jay Vosburgh <fubar@us.ibm.com> | 2006-09-22 21:54:53 -0700 |
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committer | Jeff Garzik <jeff@garzik.org> | 2006-09-25 20:08:09 -0400 |
commit | f5b2b966f032f22d3a289045a5afd4afa09f09c6 (patch) | |
tree | cb3c505d8f444438bed09353788f6c96150f68ad /Documentation/networking/bonding.txt | |
parent | 70298705bb29fb7982b85089adf17cd37b94baa7 (diff) | |
download | linux-f5b2b966f032f22d3a289045a5afd4afa09f09c6.tar.gz linux-f5b2b966f032f22d3a289045a5afd4afa09f09c6.tar.bz2 linux-f5b2b966f032f22d3a289045a5afd4afa09f09c6.zip |
[PATCH] bonding: Validate probe replies in ARP monitor
Add logic to check ARP request / reply packets used for ARP
monitor link integrity checking.
The current method simply examines the slave device to see if it
has sent and received traffic; this can be fooled by extraneous traffic.
For example, if multiple hosts running bonding are behind a common
switch, the probe traffic from the multiple instances of bonding will
update the tx/rx times on each other's slave devices.
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Diffstat (limited to 'Documentation/networking/bonding.txt')
-rw-r--r-- | Documentation/networking/bonding.txt | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt index afac780445cd..dc942eaf490f 100644 --- 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 |