1)Where the need for IPS/CS-MARS/CSC-SSM?IN WITCH SITUATION?

IPS is for blocking packets and attacks based on signatures and rules.

CSC is to block and filter urls, spam and ftp. To scan for viruses in http and emails.

MARS is a platform that collects syslogs, analyzes them and alerts you.

2)does the CSC-SSM repalce the need for Ironport WSA/ mail filter?

Their functionality overlap in some way. the they are not identical and the CSC has limitations like it can not store blocked emails etc.

3)does the CSC-SSM replace IPS as it also prevent adaware/malware?

The CSC will can for virus patterns so that part is the same.

Though it will not filter based on other rules (like SYN floods) that the IPS can trigger using signatures.

I hope it helps.

PK