In-Service Software Upgrade (ISSU) is the industry's first, comprehensive, transparent software upgrade capability for the IP/Multiprotocol Label Switching edge router. Apply bug fixes and deploy new features and services through in-service upgrade of the complete Cisco IOS Software image. This complete image, Cisco IOS ISSU capability, extends Cisco high availability innovations for minimizing planned downtime delivered earlier in Cisco IOS XR Software for service provider networks and in Cisco IOS Software Modularity for Enterprise campus and data center networks.