link aggregation, two links, two streams, yet only single bandwidth

Userlevel 2
The setup is simple:
There's a backup server using HP Teaming software to form a LAG of two gigabit copper ports with a 7100 using LACP.
Establishment of the lag works fine and the aggregate bandwidth is shown correctly as 2Gbps.
Now I know what a single stream only flows over one link, meaning link aggregation won't help to get more than 1Gbps with a single session.
That's why I tried to backup two machines simultaneously.
The outputalgorithm is set to dip-sip.
Yet there is only one link used. The second link remains idle.
(The clients are not connected to the same switch than the backupserver but they are all in the same VLAN.)
Why is the backup load not shared between both links in this case?

->show port lacp port ge.2.3-4 status summ

Global Link Aggregation state : enabled

Port Aggr Actor System Partner System

Pri: System ID: Key: Pri: System ID: Key:

ge.2.3 lag.0.1 [(32768,20b399cc6c46, 102),( 0,e4115ba8ebc2, 768)]

ge.2.4 lag.0.1 [(32768,20b399cc6c46, 102),( 0,e4115ba8ebc2, 768)]

1 reply

Userlevel 2
LACP selects the link for a flow based on a hashing algorithm. If the result for both flows is the same, the same link will be used. There is no such thing as intelligent load sharing with L2 aggregation.