Not sure about the question, but CA is certificate issuing authority which issue certificates which is needed accessing secure information (mainly https website)
If you are looking to buy some try the following http://www.namecheap.com/ http://www.trustico.ca/rapidssl/who-is-rapidssl.php
There is no security at eGTP level . Does the IP-sec sufficient to achieve the security for eGTP messages ?
Are LTE UEs generally IPSec capable? With the numerous smart devices entering the LTE space, are there standards that mandate LTE UEs to be IPsec capable?