Connecting switches - multiple connections

[brentwoodind]

I have
(2) 2824's a 2810 and a 4000 switch.

I currently have them connected with 1 crossovercable from one to the next. I would like to add connections between the switches to increase speed.
What is this called? where can I find more info?And is it supported on the switches?
when we tried it the switches started blinking and we lost connectivity.

[brentwoodind]

I beleive it is called Link Aggregation Protocol. I am reading that this is on by default. Do I need to specify what ports I am going to use?

[cenk sasmaztin]

hi
procurve switch two trunk method LACP and hp trunk

two port aggregate (may be four or eight port aggregate) increase speed

example
two switch LACP methot 2Gbps link connection
sw1(config)#trunk 49,50 trk1 lacp
sw2(config)#trunk 49,50 trk1 lacp

two switch trunk method 2Gbps link connection

sw1(config)#trunk 49,50 trk1 trunk
sw2(config)#trunk 49,50 trk1 trunk

good luck..