Users Guide

1036| Instant AP VPN Support Dell Networking W-Series ArubaOS 6.5.x| User Guide
Branch-ID Allocation
For branches deployed in distributed L3 and distributed L2 modes, the master AP in the branch and the
controller must agree upon a subnet and IP addresses to be use for DHCP services in the branch. The process
or protocol used by the master AP and the controller to determine the subnet and IP addresses used in a
branch is called BID allocation. If the branches are deployed in local only or centralized l2 only modes, the BID
allocation process is not required.
The BID allocation process performs the following functions:
l Determines the IP addresses used in a branch for distributed L2 mode
l Determines the subnet used in a branch for distributed L3 mode
l Avoids IP address or subnet overlap (that is, avoids IP conflict)
l Ensures that a branch is allocated the same subnet or range of IP addresses irrespective of which AP in the
branch assumes the role of the master in an IAP cluster
BID Allocation in a Master-Local Topology
In a master-local controller setup, the master controller runs the BID allocation algorithm and allocates BID to
the branches terminating on it and the Local controllers. The IAP sends the new branch registration requests to
the Local controller (branch coming for the first time with BIDs as -1), which in turn forwards the request to the
master controller. After receiving the registration request, the master controller allocates BIDs to the local
controller and local controller sends the BID details to the IAP. The master controller saves the BIDs in its
memory and the IAP database to avoid the collision of BID (per subnet), whereas the local controller saves the
BIDs only in its memory.
Trusted Branch Validation
The branch registration requests sent by the IAP indicates whether the IAP is managed by W-AirWave or
Central, and provides information about the IAP configuration modes on AirWave (managed or monitored
modes). Based on the information received in the registration request and the status of trusted branch
configuration, controller allows the IAP to register the branch.
Table 246 maps the IAP configuration scenario to the branch registration and trusted branch validation
process.
IAP Configuration Mode on
W-AirWave or Central
Trusted Branch DB
validation Enabled on
Controller
Branch Registration
Allowed?
Monitor mode Yes
No
Monitor mode No
Yes
Managed mode Yes
Yes
Managed mode No
Yes
Not managed by W-AirWave or
Central
Yes
No
Not managed by W-AirWave or
Central
No
Yes
Table 246: Branch Registration and Trusted Branch Validation