I was on vacation and found the internet response time at my destination was so bad, I could have a cup of tea and a chocolate biscuit while waiting for an internet response.  Someone else was streaming music with no problem – they said the internet was fine.  I tried to explain all about network performance, but the discussion got too deep.  I used the following scenario to explain the difference between response time and band width.

Imagine I wrote a letter to a supplier asking for some tapes.  I posted this, the letter was collected, put on the ferry for the 6 hour journey, and eventually arrived at the supplier the following day.   The supplier replied, and said he would send as much data as possible.  This letter went in the post, and they put my order on a lorry.
My letter (and the lorry)  went on the return  ferry.    The next day (2 days since I posted my original letter) the reply arrived through my letter box.  As I opened the letter I could hear the hiss of air brakes, and there was a knock at the door – and a very large container on a lorry.

If you do the sums…  a 1TB tape is about 10 cm * 10 cm * 2.5 cm in size.   A container with a size of  10 m * 2m * 2m can contain 160,000 tapes.
Total amount of data in the container is 160,000 TB.  This took 24 hours in the lorry. So the bandwidth was  160,000 TB in 24 * 3600 seconds = 1.8 TB/Second.

1.8TB  a second is very impressive bandwidth for a lorry  – but with a 2 day round trip time – it is impractical.

The lesson is that your network can have very high capacity – but be slow.  As an  MQ channel has an end of batch flow down, and the response back, your channel response time and throughput will be impacted by both network capacity and round trip time.

 

 

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