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://www.fs.com/products/44058.html. Then connect it using a MTP breakout cable such as https://www.fs.com/products/68049.html to get four dual fiber connectors. These are then connected to four 10G SFP+ multimode modules such as https://www.fs.com/products/11589.html. The reformer could be https://www.fs.com/products/43721.html. And finally the reformed signal can be transported using anything including DWDM modules such as https://www.fs.com/products/44058.html.
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
40G is either 4 x 10G over a single pair, or broken out into 8 fibers in the short or parallel versions.
Almost all Ethernet platforms support running most or all of their 40G ports as 1 x 40 or 4 x 10.
When using the breakout cables though your options are usually more limited. A 1U switch as a 4 x SFP+ to 1 x QSFP(28) converter will work, depending on your use case.
Spencer Ryan | Senior Systems Administrator | sryan@arbor.net Arbor Networks | The security division of NETSCOUT
+1.734.794.5033 (d) | +1.734.846.2053 (m)
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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
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
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
hey,
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.
You probably want something similar to:
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.
Indeed. Arista does (did?) make at least one platform where you can do this.
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.
You don’t use 40G modules at all. Just 4 x 10G SFP+.
The Broadcom trident chip is configured at the MAC layer for 40G, so it’s identical to a real 40G port inside.
Some more reading:
https://www.arista.com/assets/data/pdf/Whitepapers/AgilePorts_over_DWDM_Final.pdf
Spencer Ryan | Senior Systems Administrator | sryan@arbor.net<mailto:sryan@arbor.net>
Arbor Networks | The security division of NETSCOUT
+1.734.794.5033 (d) | +1.734.846.2053 (m)
www.arbornetworks.com<http://www.arbornetworks.com/>
I'm pretty sure that this is only available on 7150S which is FM6000, not
broadcom at all.
You don’t use 40G modules at all. Just 4 x 10G SFP+.
The Broadcom trident chip is configured at the MAC layer for 40G, so it’s
identical to a real 40G port inside.
Some more reading:
https://www.arista.com/assets/data/pdf/Whitepapers/
AgilePorts_over_DWDM_Final.pdf
Spencer Ryan | Senior Systems Administrator | sryan@arbor.net<mailto:sryan@
arbor.net>
Arbor Networks | The security division of NETSCOUT
+1.734.794.5033 (d) | +1.734.846.2053 (m)
www.arbornetworks.com<http://www.arbornetworks.com/>
Looks like you’re right. Too many 7xxx model numbers. Either way, same result. The MAC layer in the switch treats it like a QSFP port would be.