Alcatel Edge Routers Tout Smaller Chassis, QoS

Alcatel aims to reduce the size and expand the functionality of carrier networks with additions this week to its service edge routing product family: a 200-Gbit chassis, I/O cards and

April 14, 2004

3 Min Read
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Alcatel aims to reduce the size and expand the functionality of carrier networks with additions this week to its service edge routing product family: a 200-Gbit chassis, I/O cards and a hierarchical quality-of-service (QoS) technique.

The family was acquired from startup TiMetra Networks last July.

Alcatel gained access to three router chassis architectures when it acquired TiMetra and developed a redundant chassis that delivers a 200-Gbit full-duplex switch fabric/system capacity in an 8U-high box that consumes one-fifth rack. Other products on the market achieve that performance in a half-rack architecture, said Lindsay Newell, director of product marketing at Alcatel (

The 7750 SR-7 chassis is a seven-slot architecture: five dedicated to I/O operation and two providing switch fabric architecture redundancy. Also, the system comes with extra fan trays and power supplies to boost redundancy.

The five I/O slots can support up to 40-Gbit/second operation. But card-capacity limitations will allow designers to achieve a peak of only 20 Gbit/s today. "In the future we'll have 40-Gbit/second line cards," Newell said.To complement the chassis launch, Alcatel has crafted hardware and software options that can be rolled out across all four of its service edge router designs.

In hardware, the company is introducing two half-slot media device adapter (MDA) cards for channelized operation. The MDAs include a 12-port channelized DS-3/OC-3 card, as well as a single-port, channelized OC-12/STM-4 card. Each of the cards supports 512 channels as well as frame relay, PPP, multi-link PPP and bridge control protocol encapsulation. The cards also come with an on-board network processor that can perform on-card multilink bundling.

Multilink bundling is typically handled by sending streams to a centralized processor. But Alcatel has opted for a distributed model in its new module architectures, implementing the company's homegrown network processor on card to handle multilink bundling tasks.

"This frees up the centralized processor to do other things," Newell said.

In addition, Alcatel is supporting coarse wavelength division multiplexing through the release of small-form-factor pluggable (SFP) modules for its 7750 platforms. These modules operate over the 1,470- to-1,610-nm range, deliver up to 70 km, and can be used to establish point-to-point Ethernet links over optical rings.Alcatel is also looking to add dense wave division multiplexing (DWDM) capabilities to its systems. According to Newell, DWDM SFPs are starting to hit the market. If all goes according to plan, Alcatel will implement this capability in the 7750 family by year's end.

Alcatel expects to raise eyebrows on the software side by changing its QoS approaches in the 7750. "QoS is where we are fundamentally different," Newell said.

Since Alcatel uses its own network processor, the company was able to go into the microcode and make QoS changes to its chips without respinning silicon. With the changes, the company has created a multitiered scheduling structure for its 7750 family.

Like other boxes, Alcatel's 7750 can reserve bandwidth for high-priority traffic. In a typical system, however, this bandwidth would be locked up whether or not the bandwidth is used. That's no longer the case with the 7750. If high-priority traffic is not using the reserved bandwidth, the 7750's hierarchical QoS architecture makes the bandwidth available for lower-priority traffic schemes.

By changing the way QoS is handled, Newell said, carriers can offer different types of service-level agreements. These include a multiapplication SLA, where each application gets a reserved bandwidth but lower-priority applications can bust to use all available bandwidth. It also includes a multisite SLA, in which two offices connected to the same VPN share one SLA.Control-plane security also gained attention when Alcatel was building upgrades for the 7750. The security of data plane traffic is a concern for most system designs. "However, if the control plane is not there, the data plane will not work," Newell said.

To solve that problem, Alcatel has implemented a network processor and traffic manager on its switch fabric cards. By including these components, the system can allow control-plane traffic to gain priority over data plane traffic while encrypting all control protocols.

Alcatel's latest chassis, cards and modules will be available this month. The base price for Alcatel's 7750 SR-7 chassis is $25,000.

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