Libro sobre Proxmox maestria
Chapter 5
Once VLAN data leaves the virtual environment, a physical network switch with the VLAN feature tags each data with an ID and then directs the data to its proper destination. Each subnet should have the same VLAN ID on the virtual environment and on the physical network switch. VLAN helps reduce the broadcast traffic of multiple domains on the same network. By segmenting a large network into smaller VLAN, broadcasts can be sent only to relevant VLAN without interrupting other data traffic on the network.
Imagine a 10-lane highway connecting point A to point B. Each lane is designated to one manufacturing plant that needs to transport goods from point A to point B. Plant 1 is designated to lane number 1 (VLAN ID 1); plant 2 is designated to lane number 2 (VLAN ID 2); and so on. Even though all plants share the same highway, they each have their own lane not shared by others. VLAN follows the same logic. VLAN also provides an added security layer on a multidomain network since a user can no longer just plug into the network and capture just about any data of any domains on the network. Network segmentation is usually done with a layer 3 device such as a router. But using VLAN, significant cost saving can be achieved with an already-existing layer 2 device on the network such as a switch. There are seven layers defined by the Open Systems Interconnection (OSI) model by which network communication takes place. For in-depth details on OSI, follow the link http://en.wikipedia.org/wiki/OSI_model.
Network Address Translation/Translator (NAT) is the translation of an IP address between known and/or unknown networks. NAT allows an outbound internal network to have a designated public IP address on the Internet. So when a network device initiates an outbound connection, it uses the designated IP address instead of the local IP address designated to the device. NAT reduces the exposure of the internal IP address to the public network, thus providing protection from internal IP exposure. NAT is usually configured in the router or firewall of a network, where the policy is created for local-to-global and global-to-local IP address mapping. It should be noted that NAT is relevant for IPv4 networks. An IPv6 network diminishes the need to use NAT, because IPv6 addressing is always public.