An Intrusion Detection System (IDS) is a software application or hardware appliance that monitors traffic moving on networks and through systems to search for suspicious activity and known threats, sending up alerts when it finds such items. The overall purpose of an IDS is to inform IT personnel that a network intrusion may be taking place. Questions below are related to IDS. a. An IDS can be distinguished based on detection methods, the primary variants of which are signature detection and anomaly detection. Signature-based IDS (SIDS) applies matching methods to find a previous intrusion. In other words, an alarm signal is triggered when an intrusion signature coincides with a prior intrusion's signature that the signature database already contains. Although SIDS usually provides superior detection accuracy for familiar attacks, it fails to expose new intrusions due to the absence of matching signatures. Explain in detail with example how the Anomaly-based IDS (AIDS) can overcome the weaknesses generated from the SIDS. [6M] b. Draw and briefly explain how the watchdog approach can monitor or detect any suspicious activities that related to selective forwarding and blackhole attacks. [6M]