6506 gi 1/5 connect to loadbalancer giga 0/0
6506 gi 1/6 connect to loadbalancer giga 0/1
6506 is running CATOS
int giga 1/5
switchport access vlan 5
int giga 1/6
switchport access vlan 6
How do I configure LACP on 6506 running CATOS and aggregate giga 1/7-8 to VLAN 5 && giga1/9-10 to VLAN 6
CatOS is limited to OSI layer 2 operations so you cannot configure a L3 etherchannel on it.
the commands you have found on Reza's link should be enough to setup a L2 etherchannel using LACP.
My only doubt is that you may need to set the LACP system-id as this was a mandatory step in first IOS switches.
command for port channel protocol applies to slot numbers = modules not to channel group number, so be aware of this difference
This example shows how to specify the LACP protocol for modules 2 and 3:
Console> (enable) set channelprotocol lacp 2,3
Mod 2 is set to LACP protocol.
Mod 3 is set to LACP protocol.
the other commands for setting LACP system-id, LACP port priority are optional
Hope to help