VLAN Trunk Security | 6.7 LAYER-2 SECURITY TERMINOLOGY скачать в хорошем качестве

VLAN Trunk Security | 6.7 LAYER-2 SECURITY TERMINOLOGY

It's easy to see why virtual LANs have become extremely popular on networks of all sizes. In practical terms, multiple VLANs are pretty much the same as having multiple separate physical networks within a single organization — without the headache of managing multiple cable plants and switches. Because VLANs segment a network, creating multiple broadcast domains, they effectively allow traffic from the broadcast domains to remain isolated while increasing the network's bandwidth, availability, and security. Most managed switches are VLAN-capable, but this doesn't mean that they all perform the job equally well. The market has been flooded by thousands of switches that seem to do the job, but special consideration must be taken before making a purchase. A switch in a VLAN-enabled network needs to do a lot more than just switch packets between its ports. Core backbone switches undertake the hefty task of managing the network's VLANs to ensure everything runs smoothly. The tasks of these switches include prioritizing network packets based on their source and destination (essentially Quality of Service), ensuring all edge switches are aware of the VLANs configured in the network, continuously monitoring for possible network loops on every VLAN, switching packets between VLANs as required and ensuring network security according to their configuration. Edge switches, also known as access switches, are dedicated to the end devices: user workstations, network peripherals, and sometimes servers (most IT administrators rightly prefer to connect servers directly to the core- backbone switches). The edge switches must be compatible with the VLAN features that the core backbone switches support, otherwise unavoidable problems will arise because of incompatibilities among the switch devices. This is one reason many organizations standardize when it comes to network equipment from companies that include Cisco Systems, HP, and Juniper Networks.