Non-service affecting software upgrades for multi-service routers

Today's communications service providers are under increasing pressure to take advantage of the lower costs and increased flexibility of a unified Internet protocol (IP)-based communications network. Today there is no doubt that network elements based on IP can provide reduced costs, converge multiple network services, and collapse communications layers into a common IP/MPLS based network backbone. However, end-users have become accustomed to service quality expectations developed over the course of decades based on the circuit-switched communications network for their basic communication needs. Quality of Service schemes developed by industry standards bodies and router technology vendors, while important to meeting the quality expectations of customers, are alone insufficient to provide a satisfactory customer experience. The crux of the problem is that the routing equipment deployed by carriers today in the public network are based on routing equipment developed for enterprise applications. Enterprises have valued data integrity and fast system recovery as opposed to a standard of always-on/never down, carrier-class reliability. Enterprise applications are tolerant of routine, non-trivial, downtime maintenance windows, a concept alien to the public network downtime goals. The public network requires continuous operation, where routine maintenance is designed to occur without downtime. This paper examines the needs of service providers as it relates to meeting and exceeding customer satisfaction levels by offering high availability solutions based on applying non-service affecting upgrade capabilities, or service assured upgrade capabilities, to the new class of data routers used in service provider networks. With a service assured upgrade, service providers can ensure that software-related maintenance upgrades do not adversely affect their existing revenue stream. With the service assured upgrade, service providers can make changes to their network infrastructure with minimal disruption to their end-customer traffic. This paper defines the parameters that influence the network availability and looks at how service assured upgrades can help address outage concerns during software maintenance. It discusses the objectives and requirements for performing a service assured software upgrade and the steps taken to complete the software upgrade process. Finally, to truly appreciate the benefits of service assured software upgrade, a comparison is made with the existing software upgrade solutions offered today by the current generation of routers.