الموضوع غير مطروح فى ال ccna
عليك ب ال ccnp in switching track
هتلاقى حاجه اسمها p acl & v acl
In some situations, you need to prevent Layer 2 (L2) connectivity between end devices on a switch without the placement of the devices in different IP subnets. This setup prevents the waste of IP addresses. Private VLANs (PVLANs) allow the isolation at Layer 2 of devices in the same IP subnet. You can restrict some ports on the switch to reach only specific ports that have a default gateway, backup server, or Cisco LocalDirector attached.