10G matures

A network engineer assesses the latest round of 10G switches from Avaya, Cisco, Extreme Networks, Foundry Networks and Force10 Networks.

From the inception of its conceptual framework in late 1999 to the standardization of IEEE 802.3ae in mid 2002, 10G Ethernet has been one of the most anticipated and exciting technologies on the internetworking scene. Besides boasting throughput 10 times that of the already-blazing Gigabit Ethernet, 10G finally gives Ethernet-based networks the ability to contend with the more-established WAN technologies such as packet over SONET and ATM over high-speed OC/synchronous transfer mode circuits.

To the chagrin of many a network engineer and architect, the first round of 10G products, released less than a year after standardization, proved to be subpar. Some gear barely reached half the throughput defined in the specification, while others suffered from high amounts of latency and jitter. Potential customers quickly adopted an air of weary criticism, making it clear they would wait for more-refined products before making major purchasing decisions.

The wait has been short. Round Two of 10G products are here; the lineup looks promising.

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From the inception of its conceptual framework in late 1999 to the standardization of IEEE 802.3ae in mid 2002, 10G Ethernet has been one of the most anticipated and exciting technologies on the internetworking scene. Besides boasting throughput 10 times that of the already-blazing Gigabit Ethernet, 10G finally gives Ethernet-based networks the ability to contend with the more-established WAN technologies such as packet over SONET and ATM over high-speed OC/synchronous transfer mode circuits.

To the chagrin of many a network engineer and architect, the first round of 10G products, released less than a year after standardization, proved to be subpar. Some gear barely reached half the throughput defined in the specification, while others suffered from high amounts of latency and jitter. Potential customers quickly adopted an air of weary criticism, making it clear they would wait for more-refined products before making major purchasing decisions.

The wait has been short. Round Two of 10G products are here; the lineup looks promising.

Vendors that did not have Round One offerings are delivering their first, more mature 10G gear, while others already in the market are releasing more-refined versions of their earlier units in hopes of improving benchmarks and winning demand for their products. Most vendors say they have worked out the kinks in throughput capacity, leaving most of the differentiation to features including quality of service (QoS), IEEE 802.3ad link aggregation and reprogrammable ASICs.

The improvements are coming none too soon for a growing number of enterprise network users who need to scale past 1G Ethernet. Their justifications for 10G devices include high-volume storage-area networks and back-up segments, IP telephony, Gigabit-backed main distribution facilities, enterprise metropolitan-area networks (MAN), points of presence interconnected via 1G trunks, real-time audio and video multicasting, and data centers with switching and routing cores leveraging many 1G trunks.

"I would use 10Gig for aggregation at the enterprise core, where multiple data centers aggregate via WAN backhauls to one central border network," says Chris Rogers, a lead network engineer at InfoSpace, a provider of wireless and Internet software and application services in Bellevue, Wash. "I'd also use it anywhere throughput, latency and jitter were major issues."

Likewise for 10G's use in a management or dedicated back-up network on which lots of data needs to move quickly, says Claude Johnson, Unix systems engineer for enterprise hosting firm Digex. "In a network of thousands of systems, during a limited back-up window, I want to move as much data to my back-up servers as quickly as possible and keep those very expensive processors busy," he says.

Now with production-quality 10G units at the ready, enterprise network managers must decide which vendor has the most cost-effective, scalable products and how this fast technology best fits into their networks.

Switch vendors will have to strike a balance between price, hardware density and software features to grab the attention of these users. Avaya, Cisco, Extreme Networks, Foundry Networks and newcomer Force10 Networks are representative of the renewed 10G efforts. They each rolled out initial 10G Ethernet switches in 2002 that Network World benchmarked earlier this year.

Avaya and the Cajuns

Avaya now has two units on its 10G menu: the Cajun-series P882 MultiService Switch, for carrier cores, and the P580, more suitable for companies with midrange to high-end computing needs. With a 55G-bit/sec backplane and a forwarding rate of 40 million packet/sec, the multilayer switch does not offer much competition in terms of performance. And while users should expect to see the Cajun-series switches priced less expensively than 10G units rolled out from more-established vendors such as Cisco and Foundry, the cost is still relatively high with respect to performance and density. This is especially the case when taking into account that Force10 offers line-rate 10G ports at half the cost.

The P580, which is supposed to have a 20% speed increase over the original P550, still harbors the cross-bar chassis design that inhibited its throughput levels when tested earlier this year. It will take new testing to know whether the upgraded chassis really has resolved congestion issues in the crossbar or the 8G-bit/sec cap on the switch fabric, as Avaya says. However, it seems doubtful considering that the only major difference appears to be a boost in CPU clock speed.

The P580's scaling attributes also are somewhat weak, with a maximum of eight 10G ports, 48 1G ports and 288 10/100M bit/sec ports.

But on more positive notes, the Cajun line offers a solid set of software features, most notably for QoS. And benchmark testing against traffic shaping and queuing features has been positive, with the Avaya code enforcing traffic classes and queuing policies with strict precision. The same goes for jitter and delay.

The Cajun P580 might not be the best choice for the corporation that's looking for high scalability and full 10G performance benefits at the core and distribution layers, but it could serve as a relatively cost-effective solution for firms looking to leverage wide-scale, QoS-enhanced voice-over-IP deployments and real-time videostreaming.

The Cisco Catalysts

Opposite to Avaya on the 10G performance gradient lies Cisco, which offers a promising line of 10G products for the distribution and core layers of an enterprise campus, MAN or WAN. The most noteworthy are the four-port WS-X6704-10GE and two-port WS-X6802-10GE modules, for the Catalyst 6500-series switches and the Cisco 7600-series routers. The 6500-series switch is probably a better fit than the 7600-series router for most companies with midrange to high-end computing needs because of the scalability (48 to 576 ports of 10M, 100M or 1G Ethernet), diversity and redundancy it can provide as one manageable unit.

Combined with the new Supervisor Engine 720, which allows for an integrated 720G-bit/sec backplane, the 6500 series can accommodate up to 32 10G ports. This gives it one of the highest 10G densities available. Most startling, however, is switching performance. When the 10G modules are upgraded with distributed forwarding cards and used in combination with the Supervisor Engine, it is possible to reach a sustained forwarding rate of 48M packet/sec per card and a sustained aggregate forwarding rate of 400M bit/sec.