"RFC 6326 is TRILL support of IS-IS," Eastlake says. "That has been out for a bit now. I think this year there will be a number of switches from a number of vendors that will support the TRILL control plane."
Eastlake wouldn't speculate on why vendors have been delaying full compliance of TRILL data and control planes in their fabric switches.
"There's nothing inherently evil about using the TRILL data plane instead of the control plane," he says. "It won't interoperate with a standard TRILL control plane but people manufacture things that don't interoperate all the time. They make the business decision that that's what they want to do. Other people make things that try very hard to be very interoperable because that's the business decision that they make."
HP says it supports TRILL and its own Intelligent Resilient Framework (IRF) multichassis bonding technology for flattening the data center network. HP just announced its new 5900 line of top-of-rack switches that support both.
Arista Networks, Extreme Networks and Alcatel-Lucent all currently advocate MC-LAG as the fabric architecture for their switches. MC-LAG is an IEEE standard that is intended to replace the Ethernet Spanning Tree Protocol to improve resiliency and uptime, and reduce latency, by creating active/active network paths for load balancing and redundancy.
Since the fabrics are based on Ethernet, they should be as easy to deploy as Ethernet, according to Extreme.
"Ethernet is open," says Doug Wills, senior director of marketing at Extreme. "Why not Ethernet fabrics?"
Avaya supports the IEEE's Shortest Path Bridging (SPB) specification, an alternative to TRILL, for its VENA fabric architectures. Shortest Path Bridging is founded on the IEEE 802.1ah Provider Backbone Bridging MAC-in-MAC standard, which in the telecom world is proposed as a Layer 2 alternative to MPLS for Metro Ethernet deployments.
Some vendors, though, hedge their bets by supporting both SPB and TRILL. Huawei is in this camp.
Juniper chose to implement a tagging mechanism in the Broadcom silicon in its QFabric line because it functions like a fabric inside the switch itself; if a switch itself functions as a fabric, a fabric configured with like switches can form a flatter topology, Juniper asserts.
"You don't actually run a protocol," says Andy Ingram, worldwide managing director of data center sales for Juniper. "We use the hardware to transport the bits between the ingress and the egress point in the switch fabric."
Ingram says this has several advantages: It can be managed as a single logical device -- there is no need to manage each node of the spine and leaf topology; it lowers latency because there are fewer ASICs in the data path; and it should be less expensive because of the fewer components.
"The cards inside of a fabric switch interconnect, we don't ask them to be intelligent," Ingram says. "We're at 3kW (per port) versus something that might be 13kW. Because we're not asking it to be a switch, we can make it more efficient, we can make it faster, we can make it less expensive."
A packet is tagged and hashed on which of the routes it will take through the interconnect, Ingram says. This capability is built into the Broadcom Titan and Trident ASICs used in the QFabric nodes and interconnects.