Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

Re: Long distance links


That's (cost) a dangerous pedestal to get on. The cost of a multi-gigabit PHY is primarily governed by its opto-electronics and associated high-speed and Tx/Rx electronics such as the Tx Laser Driver and Rx Photo Diode Pre-Amplifier, Trans-Impendence Amplifier, Post Amplifier, whichever are applicable times their quantities and in consideration of the level of integration.

At multi-gigabit rates, the connection between Tx/Rx opto-electronics and associated Tx/Rx electronics are critical and packaging gets expensive depending on the architecture of the PHY.

I believe that, in general, silicon gate count for any multi-gigabit PHY gets lost in the noise.

My argument is that the architecture of the SONET OC-192 WAN PHY is far from the cheapest possible for 10 GbE based on its requirements for the highest speed opto-electronics and associated high-speed and Tx/Rx electronics. I don't want to see all 10 GbE connections encumbered with this unnecessary cost.

Best Regards,


"Booth, Brad" wrote:


I'd like to address the cost issue.  In a silicon gate count, the MAC for a WAN or a LAN should be the same cost.  As for the PHY, a WAN PHY is going to be more costly than a LAN PHY if you look at the silicon gate count.  The reason for the WAN PHY being more expensive is that the PHY is not only an encoder, it is also a framer.  Where a LAN PHY would perform encoding/decoding and translation from serial-parallel, the WAN PHY must perform all that plus add overhead and perform framing, which adds complexity and cost.

I feel that a WAN PHY and a LAN PHY are required so that LAN implementations are not burdened with the added cost and complexity of overhead and framing that are required to utilize the installed WAN OC-192 base.


Brad Booth
Austin Design Center
Intel Network Interface Division
 (512) 407-2135 office
(512) 589-4438 cellular

Richard Taborek Sr.    Tel: 650 210 8800 x101 or 408 370 9233
Principal Architect         Fax: 650 940 1898 or 408 374 3645
Transcendata, Inc.           Email: rtaborek@xxxxxxxxxxxxxxxx
1029 Corporation Way    
Palo Alto, CA 94303-4305    Alt email: rtaborek@xxxxxxxxxxxxx