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Difficulty: Very hardInterpreting JSON Encoded Data

A network automation engineer issues an HTTP GET request to a Cisco IOS-XE RESTCONF API endpoint to retrieve BGP neighbor status details. The router returns the following JSON-encoded response:

{
"Cisco-IOS-XE-bgp:bgp-state-data": {
"bgp-neighbors": [
{
"neighbor-id": "192.168.10.1",
"remote-as": 65001,
"state": "Established",
"address-family": [
{
"af-name": "ipv4-unicast",
"prefixes": {
"accepted": 42,
"sent": 15
}
},
{
"af-name": "vpnv4-unicast",
"prefixes": {
"accepted": 120,
"sent": 88
}
}
]
},
{
"neighbor-id": "192.168.20.2",
"remote-as": 65002,
"state": "Active",
"address-family": [
{
"af-name": "ipv4-unicast",
"prefixes": {
"accepted": 0,
"sent": 0
}
}
]
}
]
}
}

Match each Python dictionary lookup / data extraction expression on the left to its corresponding value or evaluated data type on the right based on the JSON response payload.

  • data["Cisco-IOS-XE-bgp:bgp-state-data"]["bgp-neighbors"][0]["address-family"][1]["prefixes"]["accepted"]120
  • data["Cisco-IOS-XE-bgp:bgp-state-data"]["bgp-neighbors"][1]["remote-as"]65002 (integer)
  • type(data["Cisco-IOS-XE-bgp:bgp-state-data"]["bgp-neighbors"][0]["neighbor-id"])str (string)
  • data["Cisco-IOS-XE-bgp:bgp-state-data"]["bgp-neighbors"][0]["address-family"][0]["af-name"]"ipv4-unicast"

Answer

Each Python expression correctly matches its evaluated output: the nested lookup for the second address family accepted prefixes of neighbor 0 evaluates to 120; the remote-as of neighbor 1 evaluates to integer 65002; the data type of the quoted neighbor-id string evaluates to str; and the first address family name of neighbor 0 evaluates to "ipv4-unicast".
Each expression matches its exact JSON path evaluation according to zero-based array indexing rules and standard JSON data type mapping into Python data structures (objects to dictionaries, lists to arrays, quoted values to strings, unquoted numbers to integers).

Step-by-Step Solution

1
Parse the top-level JSON structure and array indices using zero-based index rules.
Neighbor array index [0] corresponds to neighbor '192.168.10.1'. Neighbor array index [1] corresponds to neighbor '192.168.20.2'.
JSON arrays listed under brackets [] in Python parsing are zero-indexed.
2
Trace nested path queries down into key-value pairs and inner arrays.
Path 1 selects neighbor [0] ('192.168.10.1'), address-family array index [1] ('vpnv4-unicast'), and extracts key 'accepted' with value 120. Path 2 selects neighbor [1] ('192.168.20.2') and extracts key 'remote-as' with value 65002.
Proper path traversal requires following object keys ({}) and array indices ([]) sequentially.
3
Distinguish between JSON primitive types (string vs number/integer).
'neighbor-id' value "192.168.10.1" is enclosed in quotes (string), whereas 'remote-as' value 65002 is unquoted (integer).
JSON represents strings in double quotes and numbers without quotes.

Key Concept

JSON data structure traversal and type interpretation (arrays, objects, strings, integers)
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Topics

Interpreting JSON Encoded Data

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