When Cardano Misses a Beat

I was trying to get the page number (Cardano Explorer API) based on the timestamp of the slot, but soon realised that at times Cardano misses a slot.

for instance slot 15,779 in epoch 134 is missing:

  1. this happens when the allocated slot leader is not online?

  2. Is there other ways to get the Cardano Explorer Page based on the timestamp of the slot?

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(Changed category: this is a technically advanced topic, so Developers not Beginners.)

Yes, or there a network issues between the slot leader and the rest of the network. The slot will still be there (at the give time stamp) but there may not be a block for that slot.

There is still an exact relationship between slot number and time.

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Very good, true, thanks for the direction.

But epochs don’t all necessarily have the same amount of slots right?
So I guess I have first to scan through all the epochs to check how many slots each has.
At least there is far less epochs than pages.

Each epoch will have the same number of slots.

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just a curiosity, reading this from the Cardano Doc I had the impression there is a security parameter K that defines an epoch as 10×k slots?

What do they actually mean?

Its the duration of an epoch. The constants involved are slotDuration * 10 * k , i.e. 20s * 10 * 2160 , currently on mainnet.

so the epoch’s slots amount could change in the future?

Reading through this I have to wonder why a redundant system could not be in place to ensure every block has a slot leader that validates the network on time, if a slot leader is elected but cannot complete it’s duty how difficult would it be to also have an elected backup to fulfill the duty?

I was wondering the same thing when I did the script for the “Epochs and Slots” video (https://youtu.be/BQkJP0uUxS0) and came to the conclusion that it probably just wasn’t worth the effort. (my assumption, no sources for that)

It is build in way that empty blocks are totally fine. (as long as the majority of blocks in an epoch are created)

With the backup solution you would need to double up everything and then still design the system in a way that empty blocks are fine, because you can’t guarantee that the backup pool will be online.


Yes, slot times and number of slots are parameter that could be changed in the future.

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Tezos pools (named “bakers”) can jump in as a backup in case the randomly elected slot leader does not deliver the block. So they collect the incentives. But as @adatainment already wrote, it makes things more complicated. And as the Cardano protocol is already quite complex I guess it’s the better way to not introduce such a mechanism.

Attacking a pool to keep him offline (DDOS, hack, physical, …) is possible, but with the permanently changing slot leader it will affect only single lsots from time to time. Such a missed slot is nothing else than a short delay (20sec) of TX awaiting in the mempool before they become part of a block and confirmed in he network.


So if exchanges can stake and have Enterprise addresses is there a risk for Cardano to become centralized and controlled by big exchanges running stake pools?

I believe enterprise addresses are not going to be allowed to participate in staking.


Absolutely! If 1000 pools are online and liquid democracy in our ecosystem is instituted and 20 pools or so are the powerhouses that control the future of Cardano through the delegated stake and those exchange pools are making executive (so to speak through vote) decisions for the protocol than absolutely there is risk of centralization coming from those addresses.

@Donnybaseball @Wayne_Morgan enterprise addresses carry no staking rights, that is true. But you can’t force someone to use them. Please see this short video for details:

If Binance decides to not use enterprise addresses and run their own pools instead (and I personally bet they will) this would mean they have to manage about 100 pools (of > 1000 pools) because they have users with somewhat like 10% of all the total available Ada.

Yes, 10% is a lot but I don’t see where this is centralized or even “controlled by exchanges”. Remember it’s the users decision to give away their Ada and the staking rights to the exchange.

In my eyes the most important part of the video above is the last one about “social pressure”. (starts at 2:30) If users will decide in the future to not use exchanges that are not using enterprise addresses, things will change.


Thank you, be interesting in a few months to see where it goes.
I will just keep filling my pockets till then. I don’t have enough to put in bags😁 yet.

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I should have pointed out that 20 addresses as powerhouse voters in our ecosystem does not make it exactly centralized, as centralized has a defintion that is different, but if the 20 addresses organize to control the network then I think it could be viewed as centralized, most unlikely that this will happen as alt’s are down and people IRL think Cardano has no chance, little do they know that the price assist’s the spread to further decetralize the protocol, it is unlikely that Cardano will see any centralized idea’s control the netwrok as most people involved appear to truly want a decentralized network.

iirc the number of empty slots are used as a metric by the treasury system to validate good actors… don’t quote me on that, it’s a little fuzzy but i believe they do have a purpose