40G reforming

Hunter Fuller hf0002+nanog at uah.edu
Mon Feb 5 19:56:53 UTC 2018


I suspect that implies that you can just take a 40Gbase-SR4 module and
break it out into individual "10G" multi-mode pairs for DWDM use. Has
anyone tried this? I'm also very interested in using that strategy.

On Mon, Feb 5, 2018 at 1:36 PM Ryan, Spencer <sryan at arbor.net> wrote:

> Indeed. Arista does (did?) make at least one platform where you can do
> this.
>
> -----Original Message-----
> From: NANOG [mailto:nanog-bounces at nanog.org] On Behalf Of Marian Durkovic
> Sent: Monday, February 5, 2018 2:33 PM
> To: Baldur Norddahl <baldur.norddahl at gmail.com>
> Cc: nanog at nanog.org
> Subject: Re: 40G reforming
>
> Many switches based on BCM Trident ASIC allow you to configure 4
> consecutive
> SFP+ ports as 40G link (not LACP, but using real hardware 40G framing).
> In such case, you can plug 4 DWDM SFP+ modules directly into the switch,
> without the need for any reformer.
>
>    M.
>
> On Mon, 5 Feb 2018 20:03:33 +0100, Baldur Norddahl wrote
> > I may need to clarify that I do not want to break the port into 4x10G
> > as such. To the switch this will be an ordinary 40G link to another
> > switch far away.
> >
> > I want to take advantage of the fact that 40G is transported as four
> > individual streams. Each of the four streams are to be converted from
> > 850 nm to a 1550 DWDM channel (one channel per stream). And the
> > reverse at the other end of the link.
> >
> > The point of doing this is that 40G DWDM modules are not generally
> > available and neither are 80 km modules.
> >
> > I need a true 40G channel so 4x10G LACP is not an option here. For the
> > same reason I am unable to accept a solution that splits the 40G port
> > into 4x10G and then perhaps recombines using LACP. Instead I am
> > looking at an optical solution that is invisible to the switch hardware.
> >
> > The only doubt I have about the proposed solution is whether the frame
> > format of the 10G substreams is somehow incompatible with what goes on
> > in the reformer. As I understand these reformers they are little more
> > than two SFP(+) modules connected back to back. And therefore it
> > should not matter that the frame format may be different.
> >
> > Regards
> >
> > Baldur
> >
> > Den 5. feb. 2018 7.20 PM skrev "Paul Zugnoni" <pz at wish.com>:
> >
> > Whether a 40G port can be broken into 4x10G is dependent on the
> > router/switch hardware and the optic you use. Good news is that most
> > 40G ports are capable of being broken out into 4x10G, since a 40G port
> > is usually operating as 4x10G internally anyway to the ASIC. The QSFP
> > you'll need would be a 40G-SR4 for MTP/Multimode or 40G-LR4 for
> > MTP/Singlemode (or a lower power, less expensive equivalent). This is
> > a pretty common use of 40G ports. All 4 10G ports would then be at
> > 850nm or 1310nm, which you can then plug into any 10G SR or LR ports.
> >
> > What router or switch platform is driving the 40G?
> >
> > Paul Z
> >
> > On Mon, Feb 5, 2018 at 7:57 AM, Baldur Norddahl
> > <baldur.norddahl at gmail.com>
> > wrote:
> >
> > > Hello
> > >
> > > Is it possible to reform a 40G signal as individual 10G links?
> > >
> > > The idea is to use a 40G QSFP multimode MTP module such as
> > > https://urldefense.proofpoint.com/v2/url?u=https-3A__www.fs.com_prod
> > > ucts_44058.html&d=DwIDaQ&c=Hlvprqonr5LuCN9TN65xNw&r=Iw8ah1pcqZhOErIj
> > > aFRfuA&m=wWoshgttJT0E6q6-qJzP_ZcIrEz_EP88taPCbvAiK2Y&s=_rJfOmyDlGmPG
> > > C6M5FbhQ1V8_mho1OCpkcuYRNlaOvA&e=. Then connect it using a MTP
> > > breakout cable such as
> > > https://urldefense.proofpoint.com/v2/url?u=https-3A__www.fs.com_prod
> > >
> ucts_68049.html&d=DwIDaQ&c=Hlvprqonr5LuCN9TN65xNw&r=Iw8ah1pcqZhOErIjaFRfuA&m=wWoshgttJT0E6q6-qJzP_ZcIrEz_EP88taPCbvAiK2Y&s=Cz0mCyM3dtcHoZ7lGy7uyroI_Y7AwmKXdnYNFIF0rPI&e=
> to get four dual fiber connectors. These are then connected to four 10G
> SFP+ multimode modules such as
> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.fs.com_products_11589.html&d=DwIDaQ&c=Hlvprqonr5LuCN9TN65xNw&r=Iw8ah1pcqZhOErIjaFRfuA&m=wWoshgttJT0E6q6-qJzP_ZcIrEz_EP88taPCbvAiK2Y&s=l-9OAiUxeydRJCJc7d1kTKPVSkwQlkV4xkZFlbFxyRs&e=.
> The reformer could be
> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.fs.com_products_43721.html&d=DwIDaQ&c=Hlvprqonr5LuCN9TN65xNw&r=Iw8ah1pcqZhOErIjaFRfuA&m=wWoshgttJT0E6q6-qJzP_ZcIrEz_EP88taPCbvAiK2Y&s=NwCHiC_boNNs7zCOgJFRZ5nmZOVEPBovGYNTtdQ_pCE&e=.
> And finally the reformed signal can be transported using anything including
> DWDM modules such as
> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.fs.com_products_44058.html&d=DwIDaQ&c=Hlvprqonr5LuCN9TN65xNw&r=Iw8ah1pcqZhOErIjaFRfuA&m=wWoshgttJT0E6q6-qJzP_ZcIrEz_EP88taPCbvAiK2Y&s=_rJfOmyDlGmPGC6M5FbhQ1V8_mho1OCpkcuYRNlaOvA&e=
> .
> > >
> > > Just using fs.com as a reference to the kind of equipment I am
> > > talking about. Many other vendors offer simelar products.
> > >
> > > The motivation for doing this is to get access to the many options
> > > that are available for 10G optics but not possible with 40G.
> > >
> > > Regards,
> > >
> > > Baldur
> > >
> > >
>
> --

--
Hunter Fuller
Network Engineer
VBH Annex B-5
+1 256 824 5331

Office of Information Technology
The University of Alabama in Huntsville
Systems and Infrastructure



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