CSC-SSM module is used on ASA to scan the network traffic for HTTP, HTTPS,SMTP, POP3, FTP aprat from that it does not scan aly other traffic.
I am not 100% sure of what you asked but CSC-SSM does not have a sublet of its own neither it acts as a L3 device
The IP address that you assign to the CSC-SSM is only to manage it and also for DNS query as it needs to resolve FQDN names for the HTTP traffic through configured DNS servers; not used for routing purpose.
Please refer to the following latest configuration guide to understand better
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
[toc:faq]Introduction:This document describes details on how NAT-T
works.Background:ESP encrypts all critical information, encapsulating
the entire inner TCP/UDP datagram within an ESP header. ESP is an IP
protocol in the same sense that TCP and UDP are I...