Assuming each input data record comprises the structure in your example above you can use a FIlter node to separate out the record datetime element and split out the embedded key value pairs:

The output of the node would be as follows:

However, the above view of the output data has been sorted by the 'key' field to highlight that each input record contains multiple elements with the same key, Typically, the Pivot Data to Names node would be used to transpose the data so that the values of the key fields could be used as field names and the 'value' field's contents could be used as the corresponding value for the new field. However, in this case the node would generate an error as you cannot have multiple output fields with the same name (Cisco-AVPair in this case).

You would need to disambiguate the key field's value in line with your requirements before the data could be transposed using the Pivot Data to Names node.
The example is attached as a text file (copy the contents onto the canvas) and also as a .brg file (for LAE 6.x).
Attached files
Output_Embedded_Key_Value_Pairs.txt
Output_Embedded_Key_Value_Pairs.brg