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Load balancing using Aggregated Links (LACP)

groque
Frequent Advisor

Load balancing using Aggregated Links (LACP)

Hi guys/gals

Is it possible to load balance traffic using LACP trunk links.

For example I am running two 2910al's and I would like to create a 4Gbps trunk link in between them.

Is it possible to load balance traffic on that trunk port?

Thanks for the replies
9 REPLIES
Shadow13
Respected Contributor

Re: Load balancing using Aggregated Links (LACP)

Hi,


LACP is a trunking prot. it automaticlly load balance traffic between trunked ports but not equally, it uses something called conversation which depends on the source address and destination address of the packet, each unique SA/DA will be forwarded to one of the ports and all the traffic from the same SA/DA will take the same bath, and so on for other SA/DA combination.

for the configuration use this
#trunk lacp


= the ports that will be used in this trunk group

= fixed name for the trunk group, can be trk1, trk2,...etc

note that, the links must be with the same speed and duplex and connected to the same switches directly

If you need any other information please let me know.

Regards,
Islam Hassan
rick jones
Honored Contributor

Re: Load balancing using Aggregated Links (LACP)

Well, not *necessarily* equally - it depends on the definition of a "flow" - one example would be SA/DA pairs - how many flows there are, and whether or not the traffic of a single "flow" will be spread across more than one link in the aggregate/trunk/bond. I've not looked at the LACP spec (nor the ProCurve specs) to see if it can be set to define a flow as anything besides an SA/DA pair.

Not that it helps here specifically, but some end-systems trunking implementations can be configured to define a flow as anything from SA/DA pair through src/dst IP to full TCP (or UDP) four-tuple of local/remote IP + local/remote port.
there is no rest for the wicked yet the virtuous have no pillows
groque
Frequent Advisor

Re: Load balancing using Aggregated Links (LACP)

Thanks for the replies my main concern is all my users are connected to my second switch.

All the users have gigabit speeds and I have a four gig trunk that connects to the first switch.

The first switch contains all my servers and resoureces I don't want my users to experience any slowdowns accessing any resources. So I assume this 4 GB link will improve network performance.

All my users are on different VLAN(s) as well. Is this 4GB trunk port good enough should I look into something else? and I configured the trunk to use LACP.

Thanks again for all the help
rick jones
Honored Contributor

Re: Load balancing using Aggregated Links (LACP)

How many users (aka client MAC addresses) do you have?

How many servers (aka server MAC addresses) do you have?

If there are "enough" of each then the law of large numbers suggests things should be happiness and joy.

Unless I have high avialability concerns, I *personally* prefer to to up one level in link speed rather than aggregate (at least when possible), but then I get all my networking equipment internally.
there is no rest for the wicked yet the virtuous have no pillows
groque
Frequent Advisor

Re: Load balancing using Aggregated Links (LACP)

Hi Rick,

I have roughly 60 users and 10 main servers. I want the best performance out of my switches as possible what would you recommend?

All ports are running gigabit speeds
rick jones
Honored Contributor

Re: Load balancing using Aggregated Links (LACP)

I think you should be ok with a four-port trunk between the switches.
there is no rest for the wicked yet the virtuous have no pillows
Jeff Carrell
Honored Contributor

Re: Load balancing using Aggregated Links (LACP)

as a follow-on to this thread, there is no config "tuning" to force flows/load sharing/etc on trunk links...

SA/DA pairs is all we get...

and i would agree that based on your system, a 4G trunk should improve traffic flow as well as provide for "backup" in the event you had a link (or 2) failure...

and as always, more is better ;-)


hth...jeff
groque
Frequent Advisor

Re: Load balancing using Aggregated Links (LACP)

Thanks for the responses would a trunk be enough or should i do the sa/da pair which you guys are mentioning for better traffic flow?
Shadow13
Respected Contributor

Re: Load balancing using Aggregated Links (LACP)

SA/DA pairs cannot be manually configured, the switch automatically makes pairs based on Source Address/Destination Address of the frame.