Detect Intruders on Network

Source : https://www.google.com.pk/search?hl=en&site=imghp&tbm=isch&source=hp&biw=1366&bih=633&q=Top+tips+for+SIP+trunking&oq=Top+tips+for+SIP+trunking&gs_l=img.12…2330.2330.0.3339.1.1.0.0.0.0.190.190.0j1.1.0….0…1ac.1.64.img..1.0.0.d1Fatp3j7QY#hl=en&tbm=isch&q=Almost+a+third+of+organisations+unable+to+detect+intruders+on+network&imgrc=I5UIf2jolt7U3M%3A