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Apparatus for Communicating Between Adjacent, Stacked Switches without Cables

IP.com Disclosure Number: IPCOM000176257D
Original Publication Date: 2008-Nov-11
Included in the Prior Art Database: 2008-Nov-11
Document File: 3 page(s) / 39K

Publishing Venue

IBM

Abstract

It is desired to eliminate the cables between adjacent switches in a stack of switches. Such stacks of switches are increasing more common in storage area networks and local area networks. By eliminating these inter-switch cables, cost and set-up time is reduced as well as the installation effort and possibility of installation error is reduced. In summary, this invention allows two stacked switches to communicate directly without the need of inter-switch cables.

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Apparatus for Communicating Between Adjacent , Stacked Switches without Cables

It is desired to eliminate the cables between adjacent switches in a stack of switches. Such stacks of switches are increasing more common in storage area networks and local area networks. By eliminating these inter-switch cables, cost and set-up time is reduced as well as the installation effort and possibility of installation error is reduced. In summary, this invention allows two stacked switches to communicate directly without the need of inter-switch cables.

Figure 1 shows an exemplary embodiment of our invention, showing lower switch 101 communicating directly with upper switch 111 without the need of inter-switch cables. Switches 101 and 111 could be SAN or LAN switches that use fiber optics for inter-connect cables. Switches 101 and 111 could equally be gateway devices such as ethernet routers. Lower switch 101 comprises a lower switch cover 102, lower laser 103 for transmitting to upper phototransistor 114 of upper switch 111, lower phototransistor 104 for receiving from upper laser 113 of upper switch 111, lower collimating lens 105, lower cover 107 and lower processor 106. Similarly, upper switch 101 comprises an upper switch cover 112, upper laser 113 for transmitting to lower phototransistor 104 of lower switch 101, upper phototransistor 114 for receiving from lower laser 103 of lower switch 101, upper collimating lens 115, upper cover 117 and upper processor 116.

Processors 106 and 116 control the I/O between switches 101 and 111 respectively. Lasers 103 and 113 are of the same wavelength. This wavelength may be 405 nm for blue-violet lasers, 473 nm for blue lasers, 532 nm for green lasers, 650 nm for red lasers, 785-1065 nm for infrared lasers. Phototransistors 104 and 114 receive light at the same wavelength as lasers 103 and 113. Collimating lenses 105 and 115, lasers 103 and 113, and phototransistors 104 and 114 all have the same numerical aperture. The range of focal length for collimating lenses 105 and 115 is 1-50 mm.

The communication protocol between lasers 103 and phototransistor 114, as well as laser 113 and phototransistor 104 may be chosen from the group of SCSI, SAS (Serial Attached SCSI), iSCSI, fibre channel, ethernet, fibre channel over ethernet, SAS over ethernet, SATA, infiniband, and the like. Cover 107 could be transparent or an optical notch filter passing only the light of wavelength used by lasers 103 and 113.

Legs 118 and 119 are either of a different size or of a physically displaced distance such that switches 101 and 111 can only physically stack one way. This allows laser 103 and phototransistor 114 as well as laser 113 and phototransistor 104 to mechanically line up for data transmission. Upper switch 111 need only have one of these legs 118 and 119. Lower switch 101 has matching indentation...