# Background
our parachain has won the slot and will launch in the future.So,we fistly face that how many collators should be setup in our parachain.Here are some of my questions.

# confusing question
1. In our fist stage, we use the simple `POA` consensus.Also, we need to setup our own collators.how many collators should we setup can we ensure our parachain network's security?
2. In the second stage, we may launch `POS` mechanism.So, we need to open some seats for 
the public collators to produce block.The next two question is that how many public collators seats should we provide?  Is there a quantitative relationship between the number of our own collators and the number of public collators?
3. About the `latency` in parachain, the scene is below:   
  we set a `fixed number` of collators accounts in the chainspec.if i setup one collator to mantain the parachain, the latency is very big.But if i setup the whole fix number of collators, the latency will be small.
[![enter image description here][1]][1]
So why that? And another is that, if one collator has dropped，my parachain's network will be affected? Also, After we open some public collators seats,if some public collators dropped, it will affect our network?


  [1]: https://i.sstatic.net/ONxNB.png