Exploring layer-3 Switch construction enterprise VLAN

Layer-3 switches are quite common, so I have studied how to build enterprise VLANs for layer-3 switches. Here I will share with you, hoping they will be useful to you. The emergence of Virtual lan vlan breaks the many inherent concepts of traditional networks, making the network structure flexible, convenient, and free to do as you like.

VLAN divides user logic into working groups with relatively independent functions based on functions, applications, and other factors without considering users' physical locations, each user host is connected to a layer-3 Switch Port supporting VLAN and belongs to a VLAN. All members in the same VLAN share the broadcast information, and the broadcast information between different VLANs is isolated from each other. In this way, the entire network is divided into multiple different broadcast domains.

Traditional routers have routing forwarding, firewall, and broadcast isolation functions in the network. In a network with VLAN division, logically, the communication between different network segments still needs to be forwarded through the router. Because the data volume of communication between different VLANs is large on the LAN, if the router needs to route each packet once, as the data volume on the network increases, the router will be overwhelmed, and the router will become the bottleneck of the entire network. In this case, layer-3 switch technology emerged. Generally speaking, it is a technology that combines routing and switching technologies into one. After the router routes the first data stream, a ing table between the MAC address and IP address is generated. When the same data flow passes again, this table is used directly from the second layer instead of the second route, which eliminates the network delay caused by router selection and improves the efficiency of packet forwarding, eliminate possible network bottlenecks of the vro.

Configure VLAN

1) VLAN working mode:

Static VLAN: the Administrator specifies a VLAN for the switch port.

Dynamic VLAN: by setting the VMPSVLAN Membership Policy Server), it contains a ing table between MAC addresses and VLAN numbers. When the data frame arrives at the switch, the vswitch queries VMPS to obtain the vlan id of the corresponding MAC address.

2) ISL label: ISLInter-Switch Link) is a protocol for transmitting VLAN information and VLAN data streams between switches, between switches and routers, and between switches and servers, by configuring ISL encapsulation on the port directly connected to the switch, VLAN allocation and configuration across the switch can be performed. The International Standard for VLAN encapsulation is IEEE 802.1Q.

3) VTPVLAN Trunking Protocol): It is a Protocol for synchronizing and transmitting VLAN configuration information between layer-3 switches. Configurations on a VTP Server are transmitted to all switches in the network. VTP supports large-scale networks by reducing manual configurations. VTP has three modes:

Server Mode: allows you to create, modify, and delete VLANs and other configuration parameters for the entire VTP domain, and synchronize the latest VLAN information transmitted by other switches in this VTP domain.

Client mode: in Client mode, a vswitch cannot create, delete, or modify VLAN configurations, nor store VLAN configurations in NVRAM, however, the VLAN information transmitted by other layer-3 switches in The VTP domain can be synchronized.

Transparent mode: You can create, modify, or delete a VTP domain, or transmit the VTP broadcast information sent by other layer-3 vswitches In The VTP domain, but it is not involved in the synchronization and allocation of The VTP domain, it does not pass its own VLAN configuration to other switches in The VTP domain. Its VLAN configuration only affects itself. The switch is in Server mode by default.

4) create a VLAN. By default, the switch only has VLAN 1. You can use commands to add the required VLAN.

5) Assign the VLAN to each port of the switch. By default, all ports of the layer-3 Switch belong to VLAN 1. You can use global commands to modify the vlan id of each port of the switch. However, each port of the switch can belong to only one VLAN.

Configure layer-3 Switching

Configure the MLSP protocol so that information can be exchanged between the RP and the SE, and configure the Management port through which the MLSP can send and receive communications between the RP and the SE. Assign different VLAN Gateway Addresses for different VLANs to enable the router routing function. You can define an access policy between VLAN virtual networks as needed, which can be achieved by defining an access list.