What's wrong with this picture?

Happy Friday!

I just got the following question: Is this cabling scheme correct?

Customer wants in-band management and no fiber.

What's wrong with this picture?

What would you change?

What would you add?

What would you remove?

Please review and post your thoughts.

I'll post my response once I hear back from some of you intrepid PTP 820 community members!



the protection cable share the port with out-band managment. 

The picture is wrong about in-band management. am i right?

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As one of our friends would say, "Come on, Man!"

Pretend that you've just given this to an installer.

What questions would the installer ask?

There are plenty of things we could change about this diagram to make it easier for the installer.

What are the long-term implications of this diagram?

(In other words, what about the person who has to watch this link during its lifetime? What might help them?)


I just worked on something similar.  A customer wanted an 820S 1+1 with in-band management from ETH1 with POE.  To make this work we had to enable LACP for the ETH1 logical interface.  The switchover works fine for user data, but management can take some time to recover when going through our network depending on how fast ARP tables get updated.  When I connected my laptop directly to the switch, management does recover quickly.

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Here's the first thing we might consider adding to the picture:

How is the unit powered?

DC line or PoE?

ETH1 is the PoE port; it has built-in surge suppression.

What else can we add to the diagram to make it more useful?

Here's the next thing we should consider:

What ports are we using?

What ports are we using for management and data?

Do we want to use fiber?

Do we want in-band or out-of-band management?



The text says in-band management and no fiber, but the picture appears to show out-of-band management.

One way to accomplish this would be to connect the units with a crossover cable and use PoE to power the units. This requires the least number of surge supressors (since surge suppression is built-in if you're using ETH1 and PoE.)

Are there other tradeoffs?

(Yes. What are they?)

Are there other things we could add to this picture to make it more useful to an installer (or someone who'll use it for "as-built" documentation)?

Ha! I'd hoped that some other members would reply to this post. Everyone's waiting for the answers.


I'd suggest labeling the ports on the diagram. They are PWR, ETH1/PoE, ETH2, ETH3, and MNG.

If this is a tall tower, it would be nice to have a backup (just in case something happens to the in-band management).

Therefore, I'd run four Ethernet cables up the tower. Two cables to ETH1/PoE with power (so I don't need to add surge suppression on this line), and two cables to MNG (with surge suppression). At the base of the tower (preferably inside the telecommunications shack), I'd use PoE injectors for ETH1/PoE cables, and I'd use splitter cables and connect them with a crossover cable. Putting the splitter cables and crossover cables at the bottom reduces the complexity of the install at the top of the tower.


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