Connecting multiple GigaBlox?

I have a question regarding the suitability of the GigaBlox for what is essentially Daisy Chaining Multiple GigaBlox together.
When I link the GigaBlox together, they appear to Negotiate to 100Mb/s (red Activity LED) - and I am trying to understand is this is normal behaviour.

For simplified, but wider context of what I am trying to do is the following.

I have a 1000Mb/s connection from my computer connecting into PORT 1 on GigaBlox (A) .

PORT 4 of the GigaBlox (A) is connected to a device with a maximum connection speed of 100Mb/s.

PORT 3 of the GibaBlox (A) is connected to PORT 1 of GigaBlox (B).

PORT 4 of the GigaBlox (B) is connected to a device with a maximum connection speed of 100Mb/s

PORT 5 of the GigaBlox (B) is connected to a device with a maximum connection speed of 100Mb/s

So If I am hypothetically sending 300Mb/s of data via the 1000Mbs connection on the computer should I be able to achieve a solid 100Mbs worth of data to all three of the devices on PORT 4 / 5 of each GigaBlox…

As mentioned, currently the only green activity light I have is the one with the direct connection to the computer but not between the two GigaBlox Cards which have red indicator LEDs, which I presume means the connection between the 2 is limited to 100Mb/s also.

Is what I am trying to do impossible?

Your logic is pretty sound. A 1000Mbps connection between both GigaBlox devices would allow up to a total agreggate of 1000Mbps to be sent between all devices.

So, imagine 4 100Mbps devices on GigaBlox A, all needing to send into a device on GigaBlox B. The interconnection between both GigaBlox would be able to handle the total 400Mbps.

It’s strange that the interconnection between both GigaBlox is only negotiating to 100Mbps; it should negotiate to 1000Mbps. How are you connecting both together? What cabling are you using? Have you tried different combinations of ports on each GigaBlox for the interconnection?

I have two advices:

  1. Try powering on all the things sequentially instead of all at the same time (if you already don’t do it). Especially gigabloxes have a known autonegotiation issue. So far, it was only manifesting if connecting port 1 to port 1 etc.

  2. If your 100mbps devices communicate via an unreliable protocol (e.g. UDP), you might be losing data even if you’re way under the total bandwidth limit. If all devices transmit at the same time (and 100mbps transfer is slow, so it takes long), the buffers in the switch might get overfilled and in such case, packets start being dropped.

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Good suggestions. There is indeed a known bug when interconnecting two GigaBlox boards using a same numbered port on each, and powering them on at the same time, but usually that results in no link, rather than a 100Mbps link.

Solving that is simple though, just connect different numbered ports on each.

Thanks for the reply.
It’s good to know that it should work at least.

In terms of cabling, I am using the supplied RJ45 tails into an RJ45 Coupler. from this I am interconnecting the GigaBox cards using a 1m Cat5e cable.

In terms of swapping the ports, the only one I swapped was the confirmed 1000Mbs connection to the computer (And I just did this to confirm the Green activity LED was showing the connection speed).

I will do a little more testing on Monday. and feed back.

Hi Peco1,

On Monday, I will try your suggesting of mix and matching the ports between Gigablox.
Likewise I will test powering on separately to see what impact this has. (although in my eventual real world scenario, this will not be possible).

In terms of the 100Mbs devices - they are for the most part only listening, so although it is UDP packets, they are being sent only from the Computer with the confirmed 1000Mbs link.

Thanks. Lee

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Hi all,

Sorry for the delayed response. My entired setup for testing got buried behind a load of other equipment.

However, interestingly, I pulled out just the Gigablox and tested on my bench, as as expected did get a consistant Gb connection between then. I tried to cause issues by powering on both at the same time and in sequence.

I tried swapping to using the same port on each switch… and all times, it worked perfectly at full speed.

I then added the Gigablox switches back into units i was previously testing with and again… worked perfectly. And I have been unable to re-create the initial issue.

So while I don’t have any answers as to my initial issues, I am pleased to report it is working as expected now. (Perhaps I had a poor quality cable in the initial test).
Thank you to everyone who offered suggestions… (I will feed back if the issue re-appears).

Thanks,

Lee

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