VLAN: virtual local area network 0-4095 VLAN head and tail can not use
1 switch to divide the collision domain, can not divide the broadcast domain
2 to improve network efficiency
3 Vlan to divide the broadcast domain
Role of VLAN
1 Broadcast Control
2 Security
3 Bandwidth Utilization
4 Latency
Types of VLANs
1 Static:
use ports to divide static VLANs
2 Dynamic
use MAC addresses to divide dynamic VLANs
VLAN frame format
tag [tag]
PVID:
By default, the vlan to which the port belongs is vlan1
Access port:
when the port receives data, add a tag tag
. When receiving, delete the tag tag, otherwise the
access cannot be recognized. When sending data frames, remove the tag
[the switch will add a tag when receiving, and remove the tag when sending]
trunk 1 When sending data frames, With the flag
[if the flag is not carried, it will be marked with pvid]
2 When sending a data frame, when the ports are the same, remove the flag and send directly
[PVID switch port] Tag [data flag]
[The switch port is the same as PVID, and the sent data will be sent Tag is removed]
3 When sending data frames, if the PVID of the port is different, it will be sent directly
[The PVID of the switch port is different, and the sent data will be sent directly]
Hybrid
can be set to either access mode or trunk mode
Trunk
can support the links through which multiple vlan data are transmitted at the same time, which is called Trunk. It
supports tagging of data of different vlans, which is a protocol of vlan-id/Tag
802.1Q/dot1q [international common standard]
Original The data is increased by 4 bytes.
ISL--linter switch link [Cisco private protocol]
The original data is increased by 30 bytes
The data that access
sends and receives on the port has no label
The data sent and received by Hybrid
on the port, whether there is a label, can be manually controlled
. The characteristics of the default route
1. In one entry, it can represent all networks
2. In the routing table, it belongs to the most inaccurate route. A routing entry
[Principles of routers looking for routing tables: longest matching principle - longer - more accurate]
3 Only one port in the router passes, it is recommended to use the default route
Floating attribute:
preference: Priority, also known as the management distance
value range 1-255 [theoretically 0-255]
meaning: the stability of the route, the smaller the value, the more stable
cost: cost meaning: the smaller
the distance to the next route, the closer to the target network. The routing table selects routing entries to enter the routing table. The routing table can be formed: 1. First, compare the priorities. Next, compare the cost value, the smaller the better. Note: Only when comparing multiple paths to the same target network, the above principles are used for comparison. That is: if the target networks of multiple routing entries are not the same, it is not necessary to Comparison of preference and cost
Floating routing function: realize the backup/redundancy of the three-layer link
[Huawei]display port vlan [View the status of the vlan port]
[Huawei]ip route-static 192.168.1.0 24 192.168.3.1 preference 80
[Set the floating route, the smaller the priority value, the more stable the default value is 60]
Layer 3 switching:
realize
Layer 2 switching + Layer 3 forwarding for communication between different VLANs
Note: Each VLAN on
Cisco or Huawei Layer 3 switches corresponds to a virtual interface, and the IP address configured on the virtual interface belongs to the VLAN
Gateway IP addresses of all member hosts of