Hi @palani2010
1.How to do telnet to a destination endpoint from L3 bridge domain.
You don't. If you want to use inband management for your leafs, then you need to configure it separately from the user BDs. Here is a great article from @RedNectar on how to configure inband mgmt https://rednectar.net/2016/12/22/configuring-in-band-management-for-the-apic-on-cisco-aci-part-1-via-an-epg/
2.How does the communication happen between two bridge domains for example if i don't use contract then how does the communication happen.
I believe you actually wanted to ask what happens when endpoints from one EPG to tries to communicate with endpoints from another EPG, where EPGs are part of different BDs, and there is no contract configured between the EPGs. In this case, the communication does not happen. This is becauseACI is implemented with a whitelist policy model. Meaning you need to explicitly say which one (EPG) can communicate with another (EPG).
Take care,
Sergiu
