Hello ,
1) what are the physical requirments for logical-system in srx. do i need to have seprate physical interface for each logical system ?
> You need to have licences to have user logical system . Physical interfaces are not mandatory , but recommended .
2) is this possible design where i have the logical0system connecting external network and userlogical system conencted via dedicated lt link, not vpls switch ?
> For inter LSYS connectivity , either you need external physical link or lt connectivity via VPLS switch .