Protocol 41 is used to encapsulate IPv6 packets in IPv4 headers for transmission over an IPv4 network. This is one of the methods to implement IPv6 transition mechanisms for hosts and routers that are located on IPv4 networks. An increase in IPv4 traffic carrying protocol 41 may indicate that some hosts or routers are trying to tunnel IPv6 traffic through an IPv4 network, which could be a legitimate or malicious activity depending on the network policy. Reference := Understanding Cisco Cybersecurity Operations Fundamentals (CBROPS) - Cisco, page 177; [IPv6 Transition Mechanisms for IPv4 Domains]

Cisco Application Visibility and Control (AVC) provides features like metrics collection and exporting (D) for visibility on TCP bandwidth usage, response time, and latency. Application recognition (E) combined with deep packet inspection helps in identifying unknown software by its network traffic flow. Reference:= Cisco CyberOps Associate - Module 2: Security Concepts