Uplink Tracking

The Uplink Tracking feature enables you to assign the role of the leader to the Branch Gateway with the highest number of active uplinks in a Branch Gateway cluster. While calculating active uplinks, backup or virtual uplinks are not considered. Uplink Tracking is effective only when a preferred leader is not configured.

To enable uplink tracking for a Branch Gateway cluster, complete the following steps.

  1. In the Aruba Central app, set the filter to a Branch Gateway group.
  2. Under Manage, click Devices > Gateways.
  3. Click the Config icon.

    The gateway configuration page is displayed.

  4. Click Advanced Mode, and then click the High Availability tab.

    The High Availability details accordion is displayed. In the Clusters tab, under Cluster mode, the Automatic toggle switch and Auto Site options are enabled by default. The Auto Site clusters are created automatically and the Clusters table displays the cluster names, number of gateways, and the corresponding site name.

  5. Select the cluster profile from the Clusters table.

    The gateways assigned to the selected cluster are displayed in the Gateways in <group name> Cluster table. It consists of the Gateway and Preferred Leader columns. If the toggle switch is enabled corresponding to a gateway, it indicates that it is the preferred leader for the cluster, and the other gateway is the member. For more information, see Configuring Preferred Leader and Management VLAN at Group Level.

  6. Click the Uplink Tracking check box.

  7. Click Save Settings.

Figure 1  Uplink Tracking

Important Points to Note:

  • This method of defining the cluster leader works only when the Preferred Leader feature is not configured. If the Preferred Leader feature is configured, and a Branch Gateway is selected as the leader in the group, then the selected Branch Gateway takes precedence over the Uplink Tracking feature.

  • If the number of active uplinks on the leader becomes fewer than that on the member, the member gateway takes the role of the cluster leader and the existing leader node assumes the role of member. Since both the nodes are still part of the same Branch Gateway cluster and the cluster formation remains intact, no failure is triggered. Since member gateways in a Branch Gateway cluster always remains in hot standby mode, all the users, sessions, and GSM objects are already available on the member. Upon assuming the role of the leader, the Branch Gateway publishes new bucket map immediately, pointing active User Designated Gateways (UDGs) to itself, along with the VLAN- Designated Gateways (VDGs) and the Device Designated Gateway (DDG). The new leader becomes the VRRP Virtual Router Redundancy Protocol. VRRP is an election protocol that dynamically assigns responsibility for a virtual router to one of the VRRP routers on a LAN. master immediately after the switch without any additional delay, which is inline with the bucketmap. All connected devices receive the nodelist and bucketmap from new leader immediately after the switch.

  • Since the stability of the uplink can affect tracking priority and can trigger cluster leader switchover, there can be back to back switchovers if the uplink flaps. Hence, a 60 second hold off timer has been introduced to avoid consecutive leader switchovers. There is a 60 second pause from the previous switchover to trigger the next switchover due to changes in tracking priority. This hold off timer is applicable only for dynamic tracking priority changes such as uplink flapping. There is no hold off timer for manual configuration changes. That is, if the Uplink Tracking feature is enabled or disabled multiple times manually within a minute, the modified configuration is immediately applied. But, if the uplink flaps dynamically multiple times within 60 seconds, the changed tracking priority is applied only after hold off time expires.

  • If the preferred leader is not configured, and the Uplink Tracking checkbox is not selected, then the Branch Gateway platform is given the priority. The Branch Gateway with the higher platform becomes the cluster leader.
  • If the preferred leader is not configured, the Uplink Tracking checkbox is not selected, and both gateways have the same platform capacity, then the Branch Gateway with the higher MAC Media Access Control. A MAC address is a unique identifier assigned to network interfaces for communications on a network. address is chosen as the cluster leader.