Question about Network-Level Resiliency?

[hydakyo]

I have a question ?

when I studied CCNP , I were learned Resiliency for HA have 2 level : Network-Level Resiliency and System-Level Resiliency

but when I readed Deploying and Managing High Availability Networks, I saw Resiliency for HA have 4 level : Device Level , Transport/Link Level, Protocol Level , Application Level

So, what is correct ? 

Thanks .

[Deepak Kumar · Accepted solution]

Hi,

I say both are correct. If you are talking about only the network then System and Network level resiliency but if you are talking about complete IT Infra then it will be Device Level, Transport/Link Level, Protocol Level, Application Level.

[hydakyo]

Thanks you very much for your answer !!!