Cisco eases the economics of bandwidth protection

Bandwidth protection, a necessary but expensive staple in high-capacity fiber networks, got better and cheaper this week with Cisco Systems’ introduction of Multiprotocol Label Switching (MPLS) bandwidth protection.

The new solution to an old problem features a network architecture that uses MPLS Traffic Engineering Fast Reroute and an application developed by PARC Technologies called Tunnel Builder Pro. It minimizes and in some cases eliminates the need for non-productive redundant circuits.

While Cisco’s MPLS traffic engineering can compute the best available path in the case of a reroute of traffic, Tunnel Builder Pro enhances this capability by computing backup tunnels using an algorithm called hybrid optimization. The solution is part of and uses other features of Cisco’s IOS Software.

These other features include support of Resource Reservation Protocol (RSVP) Hellos, a mechanism used for detecting failures in Fast Ethernet, Gigabit Ethernet and other packet-over-Sonet networks.

Current methods of protection, such as SONET automatic protection switching and SDH multiplexed switching protection, require an equal amount of idle, non-revenue generating capacity to lie in wait for a network failure.

“Even the best protection schemes won’t give you 100% protection. So [carriers] need to weigh the amount of money they want to spend for it,” said Amrit Hanspal, product manager for MPLS and QoS in Cisco’s Internet technologies division.

In addition to the one-for-one backup scheme in other protection scenarios, network operators generally limit network utilization to 60% before adding more capacity. “That’s a lot of unused bandwidth,” Hanspal said.

MPLS bandwidth protection can be used in tandem with existing Sonet/SDH protection schemes, but rather than eliminating circuits used for protection, Cisco’s solution makes that bandwidth available for revenue generating traffic.

Tunnel Builder Pro uses a backup route generator that contains the algorithm for calculating the size of necessary backup tunnels. It includes a server that continuously pulls utilization and routing information from routers and an HTML/Java-based client that displays a real-time network map.

Although the $300,000 price tag for Tunnel Builder Pro is twice that of a backup OC-48 line card required for Sonet/SDH protection, Cisco estimates that the elimination of recurring operating expenses associated with maintaining the OC-48 circuits in a 10-router network (approximately $800,000) brings its MPLS bandwidth protection in at one-third the cost.

“MPLS protection gives service providers the two things they want. It reduces capital expense by allowing them to leverage existing infrastructure and at the same time cuts operating expenses be getting rid of recurring costs for unused circuits,” Hanspal said.