Siemens SCALANCE W1750D UI, Руководство по настройке

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Customizing AP Settings
8.7 Master Election and Virtual Controller
SCALANCE W1750D UI
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Configuration Manual, 02/2018, C79000-G8976-C451-02
8.7 Master Election and Virtual Controller
SCALANCE W does not require an external Mobility Controller to regulate and manage the
Wi-Fi network. Instead, one AP in every network assumes the role of VC. It coordinates,
stores, and distributes the settings required for providing a centralized functionality to
regulate and manage the Wi-Fi network. The VC is the single point of configuration and
firmware management. When configured, the VC sets up and manages the Virtual Private
Network (VPN) tunnel to a mobility controller in the data center.
The VC also functions like any other AP with full RF scalability. It also acts as a node,
coordinating DHCP address allocation for network address translated clients ensuring
mobility of the clients when they roam between different APs.
Master Election Protocol
The Master Election Protocol enables the SCALANCE W network to dynamically elect an AP
to take on a VC role and allow graceful failover to a new VC when the existing VC is not
available. This protocol ensures stability of the network during initial startup or when the VC
goes down by allowing only one AP to self-elect as a VC.
Preference to an AP with 3G/4G Card
he Master Election Protocol prefers the AP with a 3G/4G card when electing a VC for the
SCALANCE W network during the initial setup.
The VC is selected based on the following criteria:
● If there is more than one AP with 3G/4G cards, one of these APs is dynamically elected
as the VC.
● When an AP without 3G/4G card is elected as the VC but is up for less than 5 minutes,
another AP with 3G/4G card in the network is elected as the VC to replace it and the
previous VC reboots.
● When an AP without 3G/4G card is already elected as the VC and is up for more than 5
minutes, the VC will not be replaced until it goes down.
Preference to an AP with Non-Default IP
The Master Election Protocol prefers an AP with non-default IP when electing a VC for the
SCALANCE W network during initial startup. If there are more than one APs with non-default
IPs in the network, all APs with default IP will automatically reboot and the DHCP process is
used to assign new IP addresses.
Viewing Master Election Details
To verify the status of an AP and master election details, execute the following commands:
(scalance)# show election statistics (scalance)# show summary support
Manual Provisioning of Master AP
In most cases, the master election process automatically determines the best AP that can
perform the role of VC, which will apply its image and configuration to all other APs in the
same AP management VLAN. When the VC goes down, a new VC is elected.