multiple ping replies Post: 92087

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Special Forums IP Networking multiple ping replies Post 92087 by zazzybob on Wednesday 7th of December 2005 06:02:13 PM

12-07-2005

Registered User

Found this....

Quote:

Duplicated Incoming Packets
It is not uncommon to observe a short burst of duplicated traffic when the bonding device is first used, or after it has been idle for some period of time. This is most easily observed by issuing a "ping" to some other host on the network, and noticing that the output from ping flags duplicates (typically one per slave).

For example, on a bond in active-backup mode with five slaves all connected to one switch, the output may appear as follows:

# ping -n 10.0.4.2
PING 10.0.4.2 (10.0.4.2) from 10.0.3.10 : 56(84) bytes of data.
64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.7 ms
64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!)
64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!)
64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!)
64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!)
64 bytes from 10.0.4.2: icmp_seq=2 ttl=64 time=0.216 ms
64 bytes from 10.0.4.2: icmp_seq=3 ttl=64 time=0.267 ms
64 bytes from 10.0.4.2: icmp_seq=4 ttl=64 time=0.222 ms
This is not due to an error in the bonding driver, rather, it is a side effect of how many switches update their MAC forwarding tables. Initially, the switch does not associate the MAC address in the packet with a particular switch port, and so it may send the traffic to all ports until its MAC forwarding table is updated. Since the interfaces attached to the bond may occupy multiple ports on a single switch, when the switch (temporarily) floods the traffic to all ports, the bond device receives multiple copies of the same packet (one per slave device).

The duplicated packet behavior is switch dependent, some switches exhibit this, and some do not. On switches that display this behavior, it can be induced by clearing the MAC forwarding table (on most Cisco switches, the privileged command "clear mac address-table dynamic" will accomplish this).

http://linux-net.osdl.org/index.php/Bonding

Cheers
ZB

zazzybob

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LEARN ABOUT SUNOS

asadmin-jms-ping

asadmin-jms-ping(1AS)						   User Commands					     asadmin-jms-ping(1AS)

NAME

       jms-ping  - checks to see if the JMS provider is up and running

SYNOPSIS

       jms-ping   --user  admin_user  [--password  admin_password]  [--host  localhost]  [--port  4848]  [--passwordfile  filename]  [--secure|-s]
       [--terse=false] [--echo=false] [--interactive=false]

       Checks to see if the JMS provider is up and running. This command is supported in remote mode only.

OPTIONS

       --user		       authorized domain application server administrative username.

       --password	       password to administer the domain application server.

       --host		       machine name where the domain application server is running.

       --port		       port number of the domain application server listening for administration requests.

       --passwordfile	       file containing the domain application server password.

       --secure 	       if true, uses SSL/TLS to communicate with the domain application server.

       --terse		       indicates that any output data must be very concise, typically avoiding human-friendly sentences and favoring well-
			       formatted data for consumption by a script. Default is false.

       --echo		       setting to true will echo the command line statement on the standard output. Default is false.

       --interactive	       if set to true (default), only the required password options are prompted.

       Example 1: Using jms-ping

       asadmin> jms-ping --user admin --password adminadmin --host bluestar --port 4848 server1
       JMS Ping Status=RUNNING

EXIT STATUS

       0		       command executed successfully

       1		       error in executing the command

       asadmin-create-jmsdest(1AS), asadmin-delete-jmsdest(1AS), asadmin-list-jmsdest(1AS)

J2EE 1.4 SDK							    March 2004						     asadmin-jms-ping(1AS)