requirement to have redundancy for IPS appliance placed on data center design, I have digged on Cisco docs but found the Resiliency and HA (High Availability) from the IPS point of view could occur in the switches side (HSRP/Eth channel load-balance).
is there any visible way to implement the High Availability in dynamic way !!
You are correct, only one sensor at a time will pass traffic.
Spanning Tree Protocol uses layer 2 frames called BPDUs to determine if a path to the root bridge (in this case VLAN) exists. If the primary sensor stops passing layer 2 frames (a good indication that the rest of your traffic is not going to get through the sensor) then BPDUs will not pass thru the primary sensor and Spanning Tree will unblock the secondary path through the standby sensor. You may want to watch for an SNMP trap from the switch to know when that happens.
The failover cable is just an ordinary roll over cable between two ports (in the two VLANS) on the switch. I called it a failover cable because it only carries traffic when the sensor has failed to pass layer two (and above) frames.
Yes Belal, both of the things mentioned by you are correct. There is no feature available that allows 'failover' communications between two IPS boxes like Cisco Firewalls do.
Yes Etherchannel load balances the traffic to each sensor based on unique src-dst IP pairs.