Cisco adds QoS to multi-protocol label switching

Cisco Systems Inc. last week unveiled software for service providers that could entice enterprises to more readily adopt IP VPNs.

The new features for Cisco's Internetwork Operating System (IOS) software are called Multi-protocol Label Switching Guaranteed Bandwidth services (MPLS GB). The features add quality of service (QoS) to MPLS, a standard for engineering traffic in a connectionless network such as the Internet or IP VPNs, and for establishing private user groups, or tunnels, in these networks.

By adding QoS awareness to MPLS, service providers can prioritize and guarantee a level of bandwidth for enterprise traffic in a point-to-point MPLS path, mimicking the capabilities of ATM, frame relay or leased-line services. Companies can now contract with their service providers for specific service-level agreements (SLA) and committed information rates in their VPN services.

"We offer an SLA of better than 99% throughput, which is virtually guaranteed bandwidth," says Tom Wyrick, vice president of market development at GlobalOne, a user of Cisco's MPLS. GlobalOne offers an MPLS-based VPN service with three class-of-service levels for handling throughput, jitter and delay. GlobalOne has 50 customers for the service and is signing them up at a rate of five to 10 per month, Wyrick says.

Specifically, MPLS GB adds three features to Cisco's existing MPLS traffic engineering code: Differentiated Services (Diff-Serv)-aware Traffic Engineering (DS-TE), Cisco AutoBandwidth allocator and Fast Reroute (FRR).

DS-TE lets service providers offer applications with QoS guarantees based on the proposed IETF Diff-Serv standard for IP QoS. DS-TE also lets service providers perform constraint-based - policy-based - routing of traffic requiring improved delay or jitter characteristics, such as voice traffic. This feature is optimal for services such as virtual leased lines for voice toll-bypass applications, Cisco says.

"Virtual leased lines - that's hot!" says Paul Strauss, an analyst at IDC. "You still need a leased line for access, but after you get past that it's virtual leased lines between offices, which is better than VPNs because they can guarantee bandwidth. This will allow service providers to sell VPNs with enough QoS so users will feel like they have a leased line."

AutoBandwidth, a proprietary Cisco feature, dynamically increases or decreases MPLS tunnel bandwidth based on measured traffic load. This makes more efficient use of available bandwidth by letting service providers configure and monitor bandwidth for MPLS tunnels, Cisco says.

FRR enables recovery in case of link failures, preventing end-user applications from timing out and losing data. Cisco claims to replicate SONET 50 millisecond restoration time with this feature, for "thousands" of MPLS tunnels. This makes MPLS an alternative to SONET for applications such as voice trunking, Cisco says.

MPLS GB targets service providers that lease bandwidth and those that offer premium classes of bandwidth services. MPLS GB is available now in Cisco IOS release 12.0(14)ST.

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