This section introduces how to use the Neighbor Join operator to join table data of a device and its neighbor into a new table for comparison.

1.Extend a Multiple Table Operator > Neighbor Join from the Table node.

1)In the Neighbor Join node, the Qapp automatically moves the data from the two tables to one table and allocates values to the corresponding variables by the neighbor relationship in the Device Queue node.

2)If a key variable is incorrectly matched with its corresponding variable in the Device Queue, click the drop-down menu of the key variable and select the correct one. For example, this.intf <-> Table1.intf.

3)Click the Table node after the Neighbor Join node. You can see that the variables of two tables are displayed by the order of their corresponding neighbor relationships.

2.Extend a Basic Output node from the Table3 node and define the conditions to trigger the output.

1)Click the Output1 node and then click New Condition.

2)In the Define Condition dialog, define conditions as follows:

a)$this_mtu != $nbr_mtu

Tip: != means not equal to.

b)$this_bw != $nbr_bw

c)Boolean Expression : A or B

3.Extend a Draw Note node from the Output1 node and define it as follows:

1)Unselect the Map Note check box, and then select the Interface Note check box.

2)Select $this_device in the Device field, and then select $this_intf in the Interface field.

3)Enter the title of the note: Neighbor MTU/Bandwidth Mismatch.

4)Enter the content of the note. For example:
This Interface mtu: $this_mtu <------> neighbor interface mtu: $nbr_mtu
This Interface speed $this_bw <------> neighbor interface speed $nbr_bw

4.Save and run the Qapp on a map. After the Qapp execution is finished, devices with mismatched MTU or bandwidth value will be attached with a note.