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Are new IETF switching, routing specs needed?

TRILL, LISP capabilities may already be on the market from Cisco, Juniper

By , Network World
August 09, 2010 12:02 AM ET

Network World - Two high-profile specifications winding their way through the IETF promise to boost data center switching and service provider routing, but advances from Cisco and Juniper Networks raise questions about how much the specs are even needed.

For switching, the IETF is working on Transparent Interconnection of Lots of Links (TRILL), which is intended to overcome limitations of the Spanning Tree protocol in scale and topology reconvergence. For routing, the IETF is investigating the Locator/ID Separation Protocol (LISP), which is designed to improve addressing and load balancing for enterprises working with multiple ISPs.

While these may seem like solutions to long overdue networking problems, they may also be redundant with capabilities already or soon to be on the market. In the case of TRILL, Ethernet switch market leader Cisco will soon be shipping FabricPath for its Nexus 7000 switch that accomplishes the same tasks TRILL is intended to address while providing many more capabilities.

One of networking's greatest arguments: Cisco vs. Juniper 

And Cisco, the original author of LISP, acknowledges there are other techniques available today that accomplish some of the same goals as LISP. Rival Juniper concurs, enough so that it is holding off on pledging support for LISP -- as well as TRILL.

"We've already been doing this for the last two and a half years," says Dhritiman Dasqupta, senior product marketing manager for Data Center Technologies at Juniper. "What else does TRILL bring to the table? Honestly, we can't find much."

TRILL -- IETF RFC 5556 -- was authored by Joe Touch, research associate professor at the University of Southern California's Information Sciences Institute, and Radia Perlman, a software engineer at Intel who also created Spanning Tree. TRILL is intended to be a Layer 2 protocol with link state routing enhancements to enable shortest path multihop routing so users can build large-scale Ethernet and FibreChannel-over-Ethernet data center networks.

Link state routing allows the Ethernet network to discover and calculate shortest paths between TRILL nodes called Routing Bridges, or RBridges. TRILL is designed to overcome the slow topology reconvergence times associated with Spanning Tree, which limits scale and is more susceptible to link failures, but also backward compatible with existing Spanning Tree implementations.

Donald Eastlake, a principal engineer at Cisco and co-chair of the TRILL working group within the IETF, says the final TRILL RFC document will be published once a companion document that specifies IS-IS code points and data structures is agreed upon. He expects that sometime "fairly soon," while analysts expect products to populate the market in the first half of 2011.

In the meantime, vendors are implementing and testing preliminary versions of TRILL. The University of New Hampshire InterOperability Laboratory hosted a TRILL Plugfest last week; announced participants were components suppliers Broadcom and JDS Uniphase, and database giant Oracle, according to the UNH-IOL Web site.

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