Cisco S49ESK9-12231SG= operating system

IOS Software for Cisco Catalyst 4900 Series switches (Enterprise Services image with 3DES and BGP support) Control Plane Policing (CoPP): Protects the supervisor CPU by rate limiting and filtering out malicious traffic in hardware.
– Ensures network stability and availability and predictable network performance by controlling the traffic to the supervisor CPU.

Web Content Communication Protocol (WCCPv2) Layer 2 Redirection: Transparently redirects content requests to directly connected content engines via a L2/MAC address rewrite.
– Improves user response time and content availability by serving content locally on the LAN instead of the WAN.

Network Admission Control (NAC) and 802.1x Enhancements (MAC Authentication Bypass, 802.1x Inaccessible Authentication Bypass, 802.1x Unidirectional Controlled Port): Helps ensure that endpoints comply with security policies to protect networks against worms and viruses.
– Increases flexibility of NAC and 802.1x deployments.