VLAN division
There are four ways：
1. Divide VLANs according to ports
Many VLAN vendors use switch ports to divide VLAN members. The set ports are all in the same broadcast domain. For example, ports 1, 2, 3, 4, and 5 of a switch are defined as virtual network AAA, and ports 6, 7, and 8 of the same switch form a virtual network BBB. Doing so allows communication between ports and allows for upgrades to the shared network. However, this partitioning mode limits the virtual network to one switch.
The second-generation port VLAN technology allows VLANs to be divided across multiple different ports of multiple switches, and several ports on different switches can form the same virtual network.
The configuration process of dividing network members by switch ports is simple and clear. Therefore, from the moment, this way of dividing VLANs based on ports is still the most commonly used method.
2. Divide VLANs according to MAC address
This method of dividing VLANs is divided according to the MAC address of each host, that is, the host of each MAC address is configured to which group it belongs to. The biggest advantage of this VLAN division method is that when the user moves physically, that is, when switching from one switch to another, the VLAN does not need to be reconfigured. Therefore, it can be considered that this method of division based on MAC addresses is based on the user's VLAN. The disadvantage of this method is that when initializing, all users must configure it. If there are hundreds or even thousands of users, the configuration is very tiring. Moreover, this division method also leads to a reduction in switch execution efficiency, because there may be many members of VLAN groups on the port of each switch, so that broadcast packets cannot be restricted. In addition, for users who use laptops, their network cards may be replaced frequently, so that VLANs must be configured continuously.
3. Divide VLANs according to network layer
This method of dividing VLANs is divided according to the network layer address or protocol type of each host (if multi-protocol is supported). Although this method of dividing is based on the network address, such as IP address, it is not a route and has nothing to do with the routing of the network layer.
The advantage is that the user's physical location has changed, and the VLAN is not required to be reconfigured, and the VLAN can be divided according to the protocol type, which is very important for network managers. In addition, this method does not require additional frame tags to identify the VLAN, which can reduce the network's traffic. The disadvantage is its inefficiency, because checking the network layer address of each data packet requires processing time (relative to the previous two methods). Generally, switch chips can automatically check the Ethernet frame headers of data packets on the network, but making the chip able to check the IP frame headers requires higher technology and time-consuming. Of course, this is related to the implementation methods of each manufacturer.
4. Dividing VLANs according to IP multicast
IP multicast is actually a definition of VLAN, that is, a multicast group is considered to be a VLAN. This division method expands VLAN to a wide area network, so this method has greater flexibility and is easy to expand through a router. Of course, this method is not suitable for LANs, mainly because it is not efficient.
VLAN standards
For VLAN standards, we only introduce two more common standards. Of course, some companies have their own standards, such as Cisco's ISL standard. Although it is not a popular standard, due to the extensive use of Cisco Catalyst switches, ISL has become a standard that is not a standard.
· 802.10 VLAN standard
In 1995, Cisco advocated the use of the IEEE802.10 protocol. Prior to this, IEEE802.10 was once the same specification for VLAN security worldwide. Cisco attempts to transmit VLAN tags necessary in FramTagging mode on the network using the optimized 802.10 frame format. However, most members of the 802 committee oppose the promotion of 802.10. Because, this protocol is based on the FrameTagging method.
· 802.1Q
In March 1996, the IEEE802.1 Internetworking Committee concluded its revision of the initial VLAN standards. The newly issued standards further improve the VLAN architecture, unify the label formats of different manufacturers in the Fram-eTagging method, and formulate the development direction of VLAN standards in the future. The 802.1Q standard formed has been widely promoted in the industry. It has become a milestone in VLAN history. The emergence of 802.1Q broke the deadlock of virtual network dependence on a single manufacturer, and promoted the rapid development of VLAN from one aspect. In addition, the pressure from the market has caused major network manufacturers to immediately integrate the new standards into their respective products.
Here is an example of a VLAN, which is explained:
A certain IT company currently has administrative department, technical department and marketing department. VLAN division: VLAN10 of the administrative department, VLAN20 of the technology department, VLAN30 of the marketing department, and various departments can also communicate with each other.
The existing equipment is: Cisco 3640 router, one Cisco Catalyst 2924 switch, and several secondary switches.
Some of the codes in the switch configuration file are as follows:
......
!
interface vlan10
ip address 192.168.0.1
!
interface vlan20
ip address 192.168.1.1
!
interface vlan30
ip address 192.168.2.1
!
......
Some of the codes in the router configuration file are as follows:
......
interface FastEthernet 1/0.1
encapsulation isl 10
ip address 192.168.0.2
!
interface FastEthernet 1/0.2
encapsulation isl 20
ip address 192.168.1.2
!
interface FastEthernet 1/0.3
encapsulation isl 30
ip address 192.168.2.2
!
......
!
router rip
etwork 192.168.0.0
Article entry: csh Editor in charge: csh