Lock & LinkTM
Lock & LinkTM and ITPATM are add-ons which can be interfaced with the customer-specific implementation of the Ethernet stack in full compliance with the Ethernet standard.
Lock & LinkTM will reduce energy in the Ethernet stack, layer 1, 2 and 3. Other protocols, such as Infiniband, can also be provided with Cool Optics technology. For other protocols, custom specific solutions can be provided as well.
Key conditions for useful application of Lock & LinkTM technology are:
- The protocol must be synchronous and high speed
- It must have a physical media layer, a datalink layer, and a network layer, as described in the OSI layer model.
- The load of the link (that is the ratio between actual load and maximum capacity) must be smaller then 50%, otherwise savings are too small
Key element in the Lock & LinkTM technology is to really start and stop the protocol during idle periods. With present technologies, such as Fast Wake and Deep Sleep, (see Clause 78 in the Ethernet 802.3 standards,) the problem is that starting and stopping of the network takes 300 nsec up to 3000 nsec. These are unacceptable delays in a state-of-the-art network application where high performance is required. Potential savings will vary with the startup/switchdown time of the on/off protocol. See graph below.
(In normal datacenter operations, the link load is between 1 and 10 %.)
Source : ADDAPT project
When switching off, the receiving side must know that there is not a communication issue, but a controlled switching off of the link. When switching on, the link must first re-synchronize on the media level (layer 1), and then on the datalink level (layer 2). Eventually, on the network level it must be made clear that the link is re-established and communication can resume.
Re-synchronization is the reason that the known Energy Efficient Ethernet protocols such as Fast Wake and Deep Sleep, take relatively much time.
Key features of Lock & Link™
- Industry-leading fast switching on and off of Ethernet or Infiniband data streams.
- Innovative VHDL design with interfaces to the PCS and PMA layers.
- Capability to also control the PMD, Physical Media Device, within a few nanoseconds, if equipped with Fast Link technology.
- For a simple PMD with Fast Link technology and with few lanes, the off/on control is faster than the processing time of the stack, hence there is no delay or latency.
- For PMD without Fast Link technology, there will not be any latency (but only energy reduction in the network IC).
- The normal Ethernet and /or Infiniband protocol is still valid
- A Cool Optics transceiver will interwork with a standard transceiver of the same kind, be it that there will no energy saving in either transceiver.
- A Cool Optics Ethernet stack will interwork with a normal similar Ethernet Stack, be it that there will be no energy saving in either ethernet stack.
Key benefits Lock & LinkTM:
- Enables an energy reduction of typical 60% in the network stack
- Enables an energy reduction of typical 70% in the PMD (if equipped with the Fast Link technology).
- Enables less cooling features to be installed on and near the Ethernet IC’s.
- Where heat development in the transceiver is an issue, double the present capacity can be installed by applying Fast Link technology in the transceiver.
- Reduces cooling measures such as fan’s and cooling bodies in the equipment, hence can be made smaller, more silent, and less power-hungry.
- The floor capacity of the data center virtually increases, as network equipment can be made smaller.
- Cooling Machines for the data center can be made smaller because less heat to be cooled away.
- A reduction of up to 16% in the energy bill for the data center.