VPN concentrator/ASA/PIX is a piece of hardware on your network. Some vendors include: Cisco, Adtran, Juniper, etc.
If you don't know what it is, I wouldn't attempt to install it.
Any Avaya BP would have recommendations on the best solution for your network.
ACS - IP Office Implement
ACA - IP Telephony Implement
CCNA - Cisco Certified Network Associate
MCP - Microsoft Certified Professional
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