Re: [RPRWG] Phy Layer question
With regard to Leon's statement:
"I recommend that the RPR WG come up with a list of "preferred" phys for RPR
(My opinion: SONET/SDH and GE) and define their interface with RPR in some
detail, and have a general statement for other phys."
I will risk being redundant, and restate my belief that each PHY we support
will require a chapter in our standard that very specifically states how we
interface to it. There is no need to list "preferred" PHYs. We will have
separate chapters discussing how to use the PHYs we support.
Best regards,
Robert D. Love
Chair, Resilient Packet Ring Alliance
President, LAN Connect Consultants
7105 Leveret Circle Raleigh, NC 27615
Phone: 919 848-6773 Mobile: 919 810-7816
email: rdlove@xxxxxxxx Fax: 720 222-0900
----- Original Message -----
From: "Leon Bruckman" <leonb@xxxxxxxxxxxxx>
To: <stds-802-17@xxxxxxxx>
Sent: Thursday, April 19, 2001 9:03 AM
Subject: RE: [RPRWG] Phy Layer question
>
>
> Regarding the issue of RPR MAC being phy agnostic we voted and it was
> approved. Nevertheless the RPR standard will have to deal with some issues
> that are phy dependent:
>
> - Are we going to rely only on RPR alarms to perform protection switch ?
My
> position here is that we have to take into consideration layer 1 alarms
> also, then:
> - Which layer 1 alarms are the ones that trigger the protection mechanism.
> For example SONET phys can monitor for LOS, LOF, AIS (Line and Path), TIM
> (Section and Path), ... alarms, while GE phys monitor RxLOS. GR-253
defines
> that protection should be performed for LOS, LOF, AIS-L.
> - SONET APS uses also BER monitoring as a trigger to switch. Is RPR going
to
> have a BER monitoring capability to provide a similar behavior ?.
> - Is RPR going to support all the SONET APS stack (Lockout, Forced, SF,
SD,
> Manual, Exercise) ?
> - As Mike noted, the user should decide which protection mechanism should
be
> allowed first, this means that RPR should allow enough flexibility in the
> protection timers to cope with all the protection mechanisms provided by
> layer 1 phys that we consider candidates for RPR.
>
> I recommend that the RPR WG come up with a list of "preferred" phys for
RPR
> (My opinion: SONET/SDH and GE) and define their interface with RPR in some
> detail, and have a general statement for other phys.
>
> Leon
>
> -----Original Message-----
> From: Mike Takefman [mailto:tak@xxxxxxxxx]
> Sent: Thursday, April 19, 2001 5:08 AM
> To: Karighattam, Vasan
> Cc: stds-802-17@xxxxxxxx
> Subject: Re: [RPRWG] Phy Layer question
>
>
>
> Vasan,
>
> With my Chair hat on.
>
> A SONET framer does not have to be de-featured to work with an
> RPR MAC. It is my technical opinion that 802.17 will not use
> every feature of SONET but that there is no advantage
> to trying to create a reduced functionality SONET framer.
> There are plenty of SONET chips out there and no-one will
> want to redesign and reverify to save a few thousand gates.
>
> We want 802.17 to flow packets through SONET clouds, DWDM
> clouds and dark fiber. Therefore, we want to make sure we
> do not throw away any features of the layer 1 that are
> required to operate in the appropriate environment.
>
>
> With my Cisco Hat on.
>
> SRP does not use K1/K2 or any of the SONET APS signalling.
> It uses the SONET frame as a way to get a PDU from one
> node to the next. Most of our customers prefer SONET to
> GE due to the performance monitoring features.
>
> That being said, SRP can work in a SONET cloud when provided
> with a protected circuit and the SRP protection mechanism
> can be configured to allow Layer 1 to try to protect first.
> We do not encourage this mode of operation and suggest to
> customers that they use unprotected circuits and allow SRP
> to do the protection.
>
> cheers,
>
> mike