Testing APA

[Olga_1]

Hello All,

I am trying to test APA and actually see how load is balancing between lan0 and lan2 using gpm.

I started two FTP sessions and noticed that all the load goes to lan0. Is it because I use LB_MAC? I have server to switch connections.

Here is my APA configuration:

hp_apaconf:

HP_APA_INTERFACE_NAME[0]=lan900
HP_APA_LOAD_BALANCE_MODE[0]=LB_MAC
HP_APA_GROUP_CAPABILITY[0]=900


hp_apaportconf:

HP_APAPORT_INTERFACE_NAME[0]=lan0
HP_APAPORT_GROUP_CAPABILITY[0]=900
HP_APAPORT_CONFIG_MODE[0]=FEC_AUTO

HP_APAPORT_INTERFACE_NAME[1]=lan2
HP_APAPORT_GROUP_CAPABILITY[1]=900
HP_APAPORT_CONFIG_MODE[1]=FEC_AUTO

HP_APAPORT_INTERFACE_NAME[3]=lan900
HP_APAPORT_GROUP_CAPABILITY[3]=900
HP_APAPORT_PRIORITY[3]=5

HP_APAPORT_INTERFACE_NAME[4]=lan1
HP_APAPORT_CONFIG_MODE[4]=LAN_MONITOR
HP_APAPORT_PRIORITY[3]=3

Thank you,
Olga

[Steven E. Protter · Accepted solution]

Shalom Olga,

I don't think its reasonable to expect a single ftp session to balance between lan0 and lan2.

I think it is reasonable that when you have a dozen sessions the load will be split between the two lan cards.

Assuming they are both the same speed, etc.

SEP

[Olga_1]

Thank you, Steven.
I had 4 outgoing and 1 incoming sessions going at the same time each transferring about 30 G file.
It seems that all the outgoing trafic went to lan2 and incoming to lan0

I wonder where can I find detail description of how LB_MAC algorithm works?

[Ketan Kotak]

Hi,

LB_MAC will use source and dest mac address for distributing traffic.
In your case, since dest mac is probably same, APA will choose same port for the data flow.

May be you want to try LB_PORT.

If your application uses different IP, you can try LB_IP also.

You may want to read about Load Balancing algorithm in APA Users' Manual.
http://docs.hp.com/en/J4240-90035/J4240-90035.pdf

Thanks and regards,
+ Ketan Kotak

[Ketan Kotak]

Hi,

One more useful point.
The algorithm uses least bytes (right most) of both dest and source (IP address or MAC address or TCP/UDP port nubmer).

Thanks,
HTH,
+ ketan

[rick jones]

Yes it is because you used LB_MAC (as others have pointed-out). There is only one MAC pair between two systems, so there is no fanout of traffic. Similarly, if you use IP addresses, unless you assign multiple IP addresses to a NIC, there is only one pair of IP's between two systems and so no fanout.

As suggested you need to use port numbers when sending traffic between two systems. However, a couple caveats:

1) FTP actually uses two connections and the two sets of port numbers may end-up only using half the links - all the data connections may end-up with say even port numbers when the control connections have odd. If you run multiple transfers (one after the other) in the _same_ FTP session that will not be an issue.

2) Switches tend to only know how to balance by MAC or sometimes by IP address. This means that while you will get fanout on your outbound traffic, your inbound traffic may use only a single link.

Soooo, when switches are involved, you need to have more than just two MAC's involved, which likely means more than just two systems.

[Olga_1]

Thank you all for help.