I have 1 central site and 3 remotes sites connected by wireless link. Call Manager is installed on the router 3825 and already running. I need to configure and secure traffic between the central site and the 3 remotes sites and install ASA 5520 to protect the network. (see pics attached)I have 4 questions:
1.the ASA is placed just behind the router 3825, this is the best location?
2.Is it better to configure the VPN tunnels between ASA 5520 and the routers 1841 or between router 3825 and routers 1841 ?
3.I choosed the site to site VPN with IPSec AES and preshared key. How can I implement it and keep traffic and IP Telephony qos?
4.How can I configure the ASA 5520 to protect my network and keep traffic and IP Telephony qos ?