The road to virtualizing large data centres is partially blocked by the hunt for technologies that allow Layer 2 Ethernet switches to scale enough to allow large numbers virtual machines to traverse networks.
On Wednesday three major network equipment manufacturers said they recently successfully concluded a large-scale interoperability test in Ottawa of one of the technologies, the IEEE 802.1aq protocol called Shortest Path Bridging (SPB), which they say will allow enterprises and telecom carriers to greatly simplify how they create and configure large virtual networks.
Manufacturers Alcatel-Lucent, Avaya Inc. and Huawei Technologies used the help of Ottawa's Spirent Communications and Solana Networks to simulate a network of almost 200 modes and more than 400 links to pass traffic between their gear.
The test, the third in Ottawa, sets up SPB to be a legitimate challenger to proprietary network fabric solutions offered by Cisco Systems Inc., Brocade Communications Systems and Juniper Networks, said Zeus Kerravala, senior vice-president of enterprise research at Yankee Group.
"One of the questions I've heard from end users about fabrics is are these things really interoperable, or do I have to bank on a single-vendor solution?" he said.
Cisco can offer a proprietary solution called FabricPath, based on a protocol called Transparent Interconnect of Lots of Links (TRILL) because a number of enterprises have all-Cisco networks, he said. So equipment makers who go for an open standards solution like SPB have to assure customers through interoperability testing that they won't get stuck if they buy other gear.
"In a market where everyone is trying to solve the problem of getting virtual machines to run better on the network, I think interoperability testing at least brings in the viability of building a multi-vendor network," Kerravala said.
"A lot of buyers were very sceptical you wouldn't be able to do it for a year."
"The jury is still out for a lot of customers on what the best fabric solution, or next-generation data network, is going to look like," he acknowledged. "So this (latest test) is a milestone for the vendors that support Shortest Path Bridging as an alternative to (Ethernet's) Spanning Tree and TRILL."
SPB, he added, is further along the standards certification route than TRILL, which is why Cisco and Brocade have added extensions to the native TRILL protocol. Juniper has its own solution called QFabric.Peter Ashwood-Smith, a research fellow at Huawei's Ottawa lab, said in an interview that the latest test, conducted earlier this summer, used the fourth draft of the SPB specification. The final specification is expected to be approved by the IEEE by the end of this year or early next year, he said.
Shortest Path Bridging is a combination of proven existing standards, he said, including Intermediate System To Intermediate System (IS-IS), which dynamically builds the topology between network nodes; the Ethernet data plane; and the Ethernet connectivity fault management standard.
The latest test used 10 physical switches (including five Huawei Quidway S9300s, an Avaya Ethernet Routing Switch 8800 and an OmniSwitch 6900 from Alcatel-Lucent [NYSE: ALU]). Spirent's chassis-based TestCenter was used to simulate the larger network, while Solana's SmartHawk diagnostic appliance visualized the network.
Ashwood-Smith said Ottawa was chosen for the three tests because the five participants have labs there. Only one switch had to be brought in, he said, from Los Angeles.
However, the next test will likely be hosted by an enterprise or carrier that is already evaluating the protocol.
Roger Lapuh, an Avaya product line manager in the company's Ethernet switching group, said in an interview that the draft version of SPB is already available to customers in the ERS 8800.
However, he added, interoperability testing is important to help customers confused about the multiple solutions on the market. With the latest test done Avaya and others will want to start educating customers that SPB is the right solution, he said.
The group also wants to add more equipment makers. Missing from the Ottawa test group, for example, is Hewlett-Packard Co. and Force 10 Networks.
Until virtualization came along, Ethernet's Spanning Tree protocol, a ring-type protocol or a so-called split-lag protocol were the ways Ethernet networks could expand. However, each has limitations, Ashwood-Smith said. Next-generation networks need flatter topologies and broad Layer 2 networks, he said.
Not only can enterprises take advantage of SPB, he added, so can wireless carriers, who want to use Ethernet for backhaul.
Once the final standard is approved, SPB will be added by equipment makers to the operating software of their gear. It won't completely automate the configuration of a network, Ashwood-Smith said, but will go a long way.