Cisco Systems Inc. this week kicked off a new content networking initiative, targeted at Internet service providers who want to expand into application hosting and e-commerce services.
The centerpiece of the initiative is the ContentFlow architecture, which describes Cisco's plan for adding intelligence to the networking infrastructure, allowing it to better service requests coming from anywhere across the Web.
"The central issue is how to take a user request from anywhere and map it to the most appropriate service delivery point, such as a server farm, individual server or cache engine," said Cecil Christie, manager of services marketing at Cisco in San Jose, Calif.
The architecture shows how to address a complex set of requirements for providing efficient application hosting and e-commerce services across a backbone network and several data centers. Those requirements, as defined by Cisco, include a high-performance Layer 2 backbone structure, the ability to scale the service using an appropriate virtual LAN structure, a robust implementation of Border Gateway Protocol Version 4 for proper peering relationships with other ISPs, and traffic engineering capabilities provided by technologies such as IP Multicast or MPLS (Multi-Protocol Label Switching), Christie said.
On top of such an infrastructure are other requirements including local and global address resolution, accounting, efficient content distribution and tracking, as well as ensuring privacy and a consistent policy for access.
Managing the flow
The architecture Cisco proposes to meet that long list of requirements involves two primary elements: a flow management agent and a flow delivery agent.
"The flow management agent lets the network create a sustained interaction between the network and storage elements. It's always talking to the servers and cache engines to see if they are available and determines what their utilization levels are," said Christie.
With that data, agents then map user requests to the server or cache engine that can best serve the request. With end points then established, it can transfer the flow to the flow delivery agents that, again, determine the most appropriate path depending on policies defined for the flow.
"Flow delivery agents operating under a set of policies figure out whether a flow needs to be established in the first place and, if so, deliver the flow on a specific, traffic-engineered path [as dictated by the policies]," said Christie.
Those functions today are executed in Cisco's Local Director load balancing device, but Cisco will split them out and implement a flow delivery agent in the high-performance Catalyst 6500 data center switch. Splitting those functions, aside from providing a greater degree of fault tolerance and scalability for large data centers, addresses a performance issue in Local Director raised by large Cisco service providers.
"This is a different configuration used to scale delivery rates to gigabits per second, with the 6500 responsible for flow establishment and packet delivery, [while] the Local Director finds the most appropriate server," said Christie.
As part of the ContentFlow architecture, Cisco introduced a pair of new Web caching engines -- the Cache Engine 505 and Cache Engine 550 - and a new version of its Web Cache Communication Protocol. WCCP 2.0, which is implemented in Cisco's IOS internetworking software and in the Web cache engines, adds encryption of data communicated between the network and the cache engine.
Finally, the new architecture calls for two different methods for measuring the response times of servers in executing transactions. The Content Verification System is an agent-less technology that functions like a ping -- but at the content level. The Dynamic Feedback Protocol is server-based agent technology used to communicate utilization data between server and network.
To show off the ContentFlow architecture, Cisco and several partners on October 9 will Webcast live NetAid concerts from London, New York and Geneva, Switzerland, officials said. The event is expected to generate up to 1 billion hits, 10 million viewers and span over 90 data centers and 1,800 servers.