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VLAN

azad4frnd1
Level 1
Level 1

Dear All,

Could you please explain about static vlan and dynamic vlan 

Regards

Azad

3 Replies 3

InayathUlla Sharieff
Cisco Employee
Cisco Employee

Azad,

Static Vlan :- You manually configure the vlan on the box.

Ex: Switch(config)# vlan 10 >> means you are manaully/statically configure vlan 10 on the switch and so on.

Dynamic vlan:- Vlans gets assigned to the switches automatically using VMPS server.

==============Detail explanation on the same:- ================

What is Static VLAN?

Static VLANs which are also known as Port-based VLANs are created by manually assigning ports to a VLAN. When a device is connected to a port it automatically assumes the VLAN that the port is assigned to. If the user changes the port and still needs to access the same VLAN, the network administrator has to manually assign the port to the VLAN. Static VLANs are generally used to reduce broadcast and to increase the security. Since static VLANs have a small administrative overhead and provide good security than traditional switches, they are widely used. Another strong point of static VLANs is the ability to control where the user moves within a large network. By assigning specific ports on the switches in the network, the network administrators can control access and limit the network resources that can be used by the users.

What is Dynamic VLAN?

As mentioned earlier, dynamic VLANs are created by assigning the host to a VLAN when a host is plugged in to a switch using hardware addresses stored in a database. Dynamic VLANs use a central server called VMPS (VLAN Membership Policy Server). VMPS is used to handle port configurations of every switch on the VLAN network. VMPS server holds a database that contains MAC addresses of all workstations with the VLAN it belongs to. This provides a VLAN-to-MAC address mapping. This mapping scheme allows the hosts to move inside the network and connect to any switch, which is part of the VMPS network and still maintain its VLAN configuration. Initial workload required for configuring the VMPS is large hence dynamic VLANs are quite rare. When a host is connected to a switch, it is checked against the VMPS database for its VLAN membership before the port is activated and assigned to a VLAN. This prevents a foreign host accessing a network by simply plugging in a workstation to a wall socket.

What is the difference between Static VLAN and Dynamic VLAN?

Main difference between static VLANs and dynamic VLANs is that the static VLANs are configured manually by assigning ports to a VLAN while dynamic VLANs use a database that stores a VLAN-to-MAC mapping to determine the VLAN that a particular host is connected to. This provides more flexibility in dynamic VLANs allowing the hosts to move within the network as opposed to static networks. But configuring the VMPS server that contains the VLAN-to-MAC mapping requires lot of initial work. Due to this overhead network administrators tend to prefer static VLANs.

HTH

Regards

Inayath

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The vmps server builted in switch or separately we need to install

Yes. Please find details below:-

Switch:-

======

For step-by-step instructions on how to configure a Cisco Catalyst switch as a VLAN Management Policy Server (VMPS), refer to the Configure VMPS section of Configuring Dynamic Port VLAN Membership with VMPS.

With the VMPS, a Cisco Catalyst switch administrator can dynamically assign a network device to a particular VLAN. This technology is useful in sites that contain a large number of mobile users.

VMPS enables the dynamic assignment of switch ports to VLANs, based on the source MAC address of the device connected to the port. When a host is moved from a port on one switch in the network to a port on another switch in the network, the switch dynamically assigns the new port to the proper VLAN for that host.

Refer to the Components Used section of Troubleshooting the Catalyst VMPS Switch for information on the minimum software level necessary in order to run both the VMPS and VMPS client, and suggestions on how to troubleshoot the various stages and components of a Dynamic VLAN (DVLAN) assignment.

Notes:

1. The VMPS is not supported on the Cisco Catalyst 2950.

2. The Cisco Catalyst 3550 and 3548 only support the VMPS client. High-end switches such as the Catalyst 6000/6500 switches can be a VMPS server.

3. A PC cannot be configured to be a VMPS server.

Regards

Inayath

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