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

Re: XGMII or SPI-4 ?

Hi Tim,

Thanks for your comment. But right now I am totally confused.
Since the document from OIF states clearly that SPI-4 is a service interface
Link Layer and PHY Layer, I don't know if I misunderstand the meaning or I
have an
out-of-date one. Could you educate me about this thing? Thanks a lot.

Wang, WenDeh

----- Original Message -----
From: Tim Warland <twarland@xxxxxxxxxxxxxxxxxx>
To: Wang Wendeh <wendeh@xxxxxxxxxxxxx>
Cc: Ben Brown <bbrown@xxxxxxxx>; stds-802-3-hssg <stds-802-3-hssg@xxxxxxxx>
Sent: Friday, May 11, 2001 9:11 AM
Subject: Re: XGMII or SPI-4 ?

> Wang Wendeh wrote:
> > Hi Ben,
> >
> > Thank you for the valuable information. You mentioned that SPI-4 is an
> > interface
> > above MAC layer, so that means the MAC will be needed to be implemented
> > the PHY device, right? It is kind of different than before. I don't know
> > it will make
> > the PHY device to be too complicated.
> This is not entirely correct. The SPI-4 bus is used for layer 3 traffic.
> In other word, the data on SPI-4 is TCP/IP packets. In order to get
> to a PHY which is a layer 1 device, you need to go through a layer
> 2 device.
> The purpose of this study group is to define layer 1 and layer 2
> functional standards for systems implementing ethernet (layer 2)
> protocals.
> It is anticipated that component vendors will develop PHY devices
> with either a XAUI or XSBI (or potentially XGMII) bus interface
> to a layer 2 MAC device. The system interface from the MAC
> (which is beyond the scope of this study group) shall be a layer 3
> type bus such as SPI-4.
> --
> Tim Warland     P.Eng.
> Hardware Design Engineer  Broadband Products
> High Performance Optical Component Solutions
> Nortel Networks                (613)765-6634