Important Note:- In the Firewall/IPSec VPN product range the ISG series and NetScreen-5000 series firewalls support port aggregation. SSG series firewalls and NetScreen series firewalls other than NetScreen-5000 series do not have this possibility.
On the NetScreen-5000 series devices it is only possible to aggregate ports that are connected to the same ASIC chip. This means that it is only possible to aggregate for example ports ethernet 2/1 with 2/2, 2/3 with2/4, 2/5 with 2/6, and 2/7 with 2/8. 10Gbps interfaces cannot be aggregated, because they use only one interface port per ASIC chip.
Procedure to follow
Port aggregation can be used to bundle multiple physical interfaces together into one virtual aggregate interface. This aggregate interface can be used as if it is a physical interface, so it can for example be assigned an IP address and sub-interfaces can be created for it.
Here is an example on how to bundle two physical interfaces into one aggregate interface on the CLI:
set int agg1 zone Untrust
set interface ethernet1/1 aggregate aggregate1
set interface ethernet1/2 aggregate aggregate1
You can check the config using the following command
get int agg1