MPLS finds its way deeper into access services

By David Rohde

Multiprotocol Label Switching (MPLS) has quietly proven to be a hit in big carrier networks. AT&T and WorldCom have used the traffic engineering technique to essentially turn their frame relay networks into IP VPN look-alikes, as we've reported in stories about AT&T's IP-Enabled Frame Relay and WorldCom's Business Class IP, recently renamed Private IP Services.

But now MPLS is seeping into smaller carriers, particularly through integrated-access services that avoid the old dichotomy between time-division multiplexing and ATM.

For example, a carrier and premises equipment start-up in Chelmsford, Mass., is employing Multiprotocol Label Switching (MPLS) to find a niche among new local carriers who want to sell voice and data over IP.

Like numerous other vendors, the start-up, called Integral Access, pairs access aggregation gear for service-provider points of presence with a diverse set of integrated-access devices (IAD) for the customer premises.

But the trick for Integral Access is that all its devices support MPLS, which separates forwarding information from IP headers to create multiple virtual private networks - each distinguished by the application's sensitivity to latency or other network performance factors.

Integral's flagship product is the PurePacketNode, a chassis-based multiservice access concentrator for central offices, collocation sites and common wiring closets. The PurePacketNode combines the functions of an IP voice gateway, digital cross-connect and SONET multiplexer.

For the customer premises, Integral offers the PurePacketOUTburst -SB suitable for a site with a single T-1 access line. Using dynamic bandwidth allocation of the voice and data packets, the device can deliver 24 simultaneous voice calls plus up to 500K bit/sec of data over the T-1. It also provides key IP routing capabilities such Network Address Translation (NAT) and acts as a Dynamic Host Control Protocol (DHCP) server.

Integral also offers a smaller IAD called the OUTburst-Vx and a data-only device called the OUTburst-Dx. Those boxes are suitable for DSL and multiple dial-up access lines.

A carrier and premises equipment start-up is employing Multi-protocol Label Switching to find a niche among new local carriers which want to sell voice and data over IP.

Like numerous other vendors, the start-up, called Integral Access, pairs access aggregation gear for service provider points of presence with a diverse set of integrated access devices (IAD) for the customer premises.

But the trick for Integral Access is that all its devices support MPLS, a traffic-engineering technique for IP networks that's become increasingly popular in large carrier switches but is still comparatively rare in integrated access gear.

MPLS separates forwarding information from IP headers to create multiple VPNs - each distinguished by the application's sensitivity to latency or other network performance factors.

Integral's flagship product is the PurePacketNode, a chassis-based multiservice access concentrator for central offices, collocation sites and common wiring closets. The PurePacketNode combines the functions of an IP voice gateway, digital cross-connect and SONET multiplexer.

For the customer prem-ises, Integral offers the PurePacketOUTburst -SB, suitable for a site with a single T-1 access line. Using dynamic bandwidth allocation of the voice and data packets, the device can deliver 24 simultaneous voice calls plus up to 500K bit/sec of data over the T-1. It also provides key IP routing capabilities such as network address translation and acts as a Dynamic Host Configuration Protocol server.

Integral also offers a smaller IAD called the Outburst-Vx and a data-only device called the Outburst-Dx. Those boxes are suitable for DSL and multiple dial-up access lines.

Integral's approach appeals to Westelcom, a competitive local exchange carrier (CLEC) in Plattsburgh, N.Y. The CLEC is installing PurePacketNode in one of its central offices - the company is actually a subsidiary of a local, non-Bell incumbent telephone company - and collocating them in four Verizon central offices for expanded geographic reach.

Westelcom will install the IADs on customer premises to offer a variety of services, from a mixed voice/data offering for business T-1 customers to a residential service combining 384K bit/sec Internet access with two ordinary phone lines.

Westelcom Corporate Engineer Eric Kreckel says the CLEC didn't want to base new integrated services around the variety of available IADs based on time-division multiplexing. But he also passed on newer ATM-based IADs and carrier access concentrators that turn IP applications into cells and transport them via ATM's standard classes of service.

The problem with ATM is the network efficiency for small offices and residential customers. "Once you get through the IP encapsulation and the ATM cell tax, you're transporting more header than data," he says.

Integral has also sold into a group of CLECs in Minnesota, including Jaguar Communications and HickoryTech.

One key for IAD vendors to appealing to these CLECs, says RHK analyst Claude Romans, is building interfaces from the aggregation gear to classic Class 5 telephone switches and newer SoftSwitches. Integral didn't initially support classic telephone company switches, he says, but eventually added support for the GR303 protocol for voice concentration typically used by these devices.

Indeed, Kreckel says GR303 support was important for Westelcom.

We'll have more about Integral Access in next week's print edition of Network World, including the first experience of a CLEC in upstate New York using the gear.