Good book for telecommunications people

A very good book for getting those with a telecomm background up to speed on network security for VoIP. I only saw one mistake (probably a typo), which is quite acceptable. Those with a background in network security can also use the book to get familiar with those aspects which apply to VoIP. The only real problem is that the book is several years old.

Other Reviews

• Good book for telecommunications people
• for begginer, it only explains basic elements in PBX, and basic terms of VoIP with Asterisk
• Practical VoIP Security