Virtex-4 RocketIO and G.709 OTU-2

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Hi all,
Did some company already implemented G.709 OTU-2 on Virtex-4 using the
RocketIO?
In other words: the maximum bitrate of RocketIO is 10.3125 but OTU-2 is
10.709. Should Virtex-4 be definitively excluded or are there some
tricks to achieve that challenge?

Cheers
Mehdi


Re: Virtex-4 RocketIO and G.709 OTU-2
Unfortunately, even OC-192 is excluded form Virtex- 4 (ug076.pdf :
"Payload compatible only"), so no hope for OTU-2 I think.
We have to wait Virtex-5 family ?


Re: Virtex-4 RocketIO and G.709 OTU-2

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No.  That is unlikely to have sufficient jitter performance, due to
certain compromises that must be made when putting an MGT on an FPGA.
In particular, it's likely to use a ring oscillator rather than an LC
oscillator which would have better perfomance.

Use an external SERDES designed for G.707 / G.709 work.

Note that (before they discontinued it) Xilinx's standalone SERDES
didn't meet the SONET jitter requirements either, so getting these
things to work is clearly not a trivial task.

Regards,
Allan

Re: Virtex-4 RocketIO and G.709 OTU-2
Can you indicate me such a SERDES. It's perfect if its output is
64bits. Also it shoulden't do FEC stuff. FEC is planned to be done on
FPGA.

Thnaks in advance
Mehdi

Allan Herriman wrote:
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Re: Virtex-4 RocketIO and G.709 OTU-2

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Most 10Gb/s SERDES parts seem to have 16 bit interfaces, probably
because there's common interface definition called SFI-4 that has 16
LVDS pairs clocked at 622-670MHz.

Xilinx has an app note called XAPP 622 that describes how to implement
such an interface on an FPGA.

Did you use Google?  You would have found SERDES manufacturers such as
PMC, AMCC, Broadcom, etc.

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Thanks for the top-post!

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Re: Virtex-4 RocketIO and G.709 OTU-2

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Is jitter the only limitation? Most fiber optic transceivers (XFP & friends)
have eye openers of their own and resynchronize everything anyway.

regards, Gerhard



Re: Virtex-4 RocketIO and G.709 OTU-2
The -11X speed grade is dead as of this week.  Do this some other way.


Re: Virtex-4 RocketIO and G.709 OTU-2
I didn't see this info on Xilinx's site! Is it official?
On the last Virtex-4 datasheet (ds302) the speed grade -12x disapeared
but not the -11x!

mike_la_jolla wrote:
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Re: Virtex-4 RocketIO and G.709 OTU-2
On Fri, 07 Apr 2006 16:50:08 +0200, Gerhard Hoffmann

wrote:
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An XFP will have a JTF bandwidth in the order of 1MHz.  A SERDES will
have a JTF bandwidth of 1-2 orders of magnitude less than that, so
resynchronisation in the XFP doesn't solve all the jitter problems.

Regards,
Allan

Re: Virtex-4 RocketIO and G.709 OTU-2
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I have seen that note as well. Can someone explain what "Payload
compatible only" means?

Re: Virtex-4 RocketIO and G.709 OTU-2
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I have seen that note as well. Can someone explain what "Payload
compatible only" means?

Re: Virtex-4 RocketIO and G.709 OTU-2
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I have seen that note as well. Can someone explain what "Payload
compatible only" means?

Re: Virtex-4 RocketIO and G.709 OTU-2
I have seen that note as well, but I don't understand it.

Can someone explain what "Payload compatible only" means?


Re: Virtex-4 RocketIO and G.709 OTU-2
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I don't know about this protocol exactly, but for 10GBit Ethernet, which
is a similar speed, you can use interfaces like XAUI (4x3.125Gbit) - if
there is either a standard interface or a chip that could do this for
you, then V4 could still be a contender.

Jeremy

Re: Virtex-4 RocketIO and G.709 OTU-2
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even if ...
Does anyone really have those Virtex4 in that super-speedgrade -12X?
To me it sounds like they won't be available anytime soon ... :-(


bye,
Michael

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