350-401 Model-Driven Telemetry Practice Test 2 — 15 Questions

Question 1

An engineer retrieves telemetry data from a Cisco IOS-XE device using RESTCONF and receives the following response:

```json
{
  "ietf-interfaces:interfaces": {
    "interface": [
      {
        "name": "GigabitEthernet1",
        "type": "iana-if-type:ethernetCsmacd",
        "enabled": true,
        "ipv4": {
          "address": [
            {
              "ip": "192.168.1.1",
              "netmask": "255.255.255.0"
            }
          ]
        }
      }
    ]
  }
}
```

What is the correct way to access the IP address of the interface using Python?

Accepted Answer

data['ietf-interfaces:interfaces']['interface'][0]['ipv4']['address'][0]['ip']. The JSON response is nested. To access the IP address, you need to navigate through the dictionary: data['ietf-interfaces:interfaces']['interface'][0]['ipv4']['address'][0]['ip']. This returns '192.168.1.1'.

Answer

data['interface'][0]['ipv4']['address']['ip']

Answer

data['interfaces']['interface']['ipv4']['address']['ip']

Answer

data['ietf-interfaces:interfaces']['interface']['ipv4']['address'][0]['ip']

Question 2

An Ansible playbook uses the cisco.ios.ios_telemetry module to configure a telemetry subscription:

```yaml
---
- name: Configure telemetry subscription
  hosts: ios_xe
  gather_facts: no
  tasks:
    - name: Create telemetry subscription
      cisco.ios.ios_telemetry:
        state: present
        subscription_id: 300
        receiver:
          ip: 10.1.1.100
          port: 50051
          protocol: grpc-tcp
        source_ip: 10.1.1.1
        encoding: kvgpb
        filter:
          xpath: /interfaces/interface/state/counters
        update_policy:
          period: 10000
```

What is the purpose of the 'state: present' parameter?

Accepted Answer

It ensures the subscription is present in the running configuration.. The 'state: present' parameter ensures that the telemetry subscription is created if it does not exist, or updated if it does. It is a common Ansible module parameter that idempotently manages configuration.

Answer

It checks if the subscription is currently active.

Answer

It removes the subscription if it exists.

Answer

It displays the current subscription configuration.

Question 3

A network engineer uses the following Python code to subscribe to telemetry data from a Cisco IOS-XE device via NETCONF using the YANG module 'Cisco-IOS-XE-mdt-oper': ```python from ncclient import manager m = manager.connect( host='192.168.1.1', port=830, username='admin', password='cisco', hostkey_verify=False ) # Create a telemetry subscription subscription = '''

400

yang-push encode-kvgpb 5000 /interfaces/interface/state/counters

10.1.1.100

50051 grpc-tcp

''' reply = m.edit_config(target='running', config=subscription) print(reply.xml) m.close_session() ``` What is the issue with this code?

Accepted Answer

The code uses target='running' which may not be writable; it should use target='candidate' and then commit.. The NETCONF edit-config operation with target='running' is used to directly modify the running configuration. However, on many Cisco IOS-XE devices, the running configuration is not directly writable via NETCONF; you must use target='candidate' and then commit. Additionally, the XML namespace for mdt-config-data may be incorrect; the correct namespace is 'http://cisco.com/ns/yang/Cisco-IOS-XE-mdt-cfg' but the module name is 'Cisco-IOS-XE-mdt-cfg'. However, the primary issue is that the code uses target='running' instead of target='candidate' and a separate commit operation.

Answer

The XML namespace is incorrect; it should be 'http://cisco.com/ns/yang/Cisco-IOS-XE-mdt-oper'.

Answer

The xpath is invalid; it should be '/interfaces/interface/state/counters'.

Answer

The subscription-id should be a string, not an integer.

Question 4

Consider the following configuration snippet on a Cisco IOS-XE device:

telemetry ietf subscription 100
 encoding encode-kvgpb
 filter xpath /interfaces/interface/state/counters
 stream yang-push
 update-policy periodic 500
 receiver ip address 10.1.1.1 50000 protocol grpc

What is the effect of this configuration?

Accepted Answer

It streams interface counter data every 500 milliseconds to the collector at 10.1.1.1:50000 using gRPC.. This configuration creates an IETF telemetry subscription that periodically pushes interface counter data to a gRPC collector.

Answer

It streams interface counter data every 500 seconds to the collector at 10.1.1.1:50000 using gRPC.

Answer

It streams the entire YANG model for interfaces to the collector, not just counters.

Answer

It uses the NETCONF protocol to send data to the collector.

Question 5

Examine the following telemetry configuration on a Cisco IOS-XE device:

telemetry ietf subscription 200
 encoding encode-kvgpb
 filter xpath /interfaces/interface[name='GigabitEthernet0/0/0']/state
 stream yang-push
 update-policy on-change
 receiver ip address 192.168.1.100 50001 protocol grpc

Which statement is true about this configuration?

Accepted Answer

Data is pushed only when a change occurs in the state of GigabitEthernet0/0/0.. This subscription uses on-change update policy, so data is pushed only when a change occurs in the specified subtree.

Answer

Data is pushed every 200 seconds to the collector.

Answer

The subscription uses JSON encoding.

Answer

The filter selects all interfaces, not just GigabitEthernet0/0/0.

Question 6

Review the following telemetry configuration snippet:

telemetry ietf subscription 300
 encoding encode-kvgpb
 filter xpath /interfaces/interface/state/counters
 stream yang-push
 update-policy periodic 100
 receiver ip address 10.1.1.1 50000 protocol grpc

What is missing or incorrect in this configuration?

Accepted Answer

The receiver should specify a source interface to ensure consistent source IP for the telemetry stream.. The configuration is missing a source interface or source IP address, which is recommended for telemetry receivers to ensure reachability and consistent source addressing.

Answer

The configuration is correct and complete.

Answer

The update-policy period of 100 milliseconds is too fast and may cause performance issues.

Answer

The encoding should be encode-xml for IETF subscriptions.

Question 7

Given this telemetry configuration on a Cisco IOS-XE device:

telemetry ietf subscription 400
 encoding encode-kvgpb
 filter xpath /interfaces/interface/state
 stream yang-push
 update-policy periodic 1000
 receiver ip address 10.1.1.1 50000 protocol grpc
 source-interface Loopback0

What is the effect of the source-interface Loopback0 command?

Accepted Answer

It uses the IP address of Loopback0 as the source for telemetry packets to the receiver.. The source-interface command ensures that all telemetry packets sent to the receiver use the IP address of Loopback0 as the source.

Answer

It forces the telemetry receiver to listen on Loopback0.

Answer

It restricts the telemetry data to only Loopback0 interface counters.

Answer

It changes the update policy to on-change for Loopback0.

Question 8

Examine the following telemetry configuration:

telemetry ietf subscription 500
 encoding encode-kvgpb
 filter xpath /interfaces/interface/state/counters
 stream yang-push
 update-policy periodic 500
 receiver ip address 10.1.1.1 50000 protocol grpc

A network engineer wants to add a second receiver for redundancy. Which additional configuration is correct?

Accepted Answer

Add a second receiver under the same subscription: receiver ip address 10.1.1.2 50000 protocol grpc. To add a second receiver, you add another receiver line under the same subscription.

Answer

Create a new subscription with the same parameters and a different receiver.

Answer

Modify the existing receiver to use multicast address 239.1.1.1.

Answer

Use the backup-receiver command under the receiver.

Question 9

Consider the following telemetry configuration on a Cisco IOS-XE device:

telemetry ietf subscription 600
 encoding encode-kvgpb
 filter xpath /interfaces/interface/state
 stream yang-push
 update-policy on-change
 receiver ip address 10.1.1.1 50000 protocol grpc

What is a potential issue with this configuration?

Accepted Answer

The filter XPath is too broad and may cause excessive CPU usage on frequent changes.. On-change subscriptions can generate high CPU load if the monitored data changes frequently, which may impact device performance.

Answer

The on-change policy will not work without a periodic fallback.

Answer

The receiver IP address must be on the same subnet as the device.

Answer

The encoding should be encode-xml for on-change subscriptions.

Question 10

What is the default update interval for a Cisco IOS-XE telemetry subscription when using update-policy periodic without specifying a value?

Accepted Answer

10000 milliseconds. The default periodic interval is 10000 milliseconds (10 seconds) if not explicitly configured.

Answer

1000 milliseconds

Answer

5000 milliseconds

Answer

The command requires a value; there is no default.

Question 11

Which of the following is a valid transport protocol for model-driven telemetry receivers on Cisco IOS-XE?

Accepted Answer

gRPC. gRPC is a supported transport protocol for telemetry receivers, along with gNMI and others.

Answer

HTTP

Answer

FTP

Answer

SNMP

Question 12

What is the purpose of the 'source-interface' command under a telemetry receiver configuration?

Accepted Answer

It sets the source IP address for telemetry packets sent to the receiver.. The source-interface command ensures that telemetry packets use a consistent source IP address, which helps with firewall rules and receiver identification.

Answer

It specifies the interface from which the telemetry data is collected.

Answer

It limits telemetry data to only that interface's statistics.

Answer

It enables telemetry on that interface for incoming data.

Question 13

Drag and drop the steps of the gRPC dial-out telemetry subscription flow into the correct order, from first to last.

Accepted Answer

Configure telemetry receiver with IP and port. The correct order is: first, configure the telemetry receiver (destination) on the network device. Next, define a sensor group to specify which YANG data paths to collect. Then, create a subscription associating the sensor group with the receiver. After that, enable the subscription to start streaming data. Finally, the device streams telemetry data to the receiver.

Question 14

Drag and drop the steps of configuring NETCONF YANG-based telemetry with on-change subscription into the correct order, from first to last.

Accepted Answer

Enable NETCONF on the device. First, enable NETCONF on the device. Then, define a sensor group that includes the YANG paths to monitor for changes. Next, create a subscription that specifies the sensor group, a receiver, and the on-change update policy. After that, apply the subscription to activate it. Finally, the device sends updates only when the monitored data changes.

Question 15

Drag and drop the steps of troubleshooting a model-driven telemetry subscription using CLI into the correct order, from first to last.

Accepted Answer

Verify telemetry receiver configuration. First, verify the telemetry receiver configuration to ensure the destination is correct. Next, check the sensor group to confirm the correct YANG paths are included. Then, examine the subscription status to see if it is active. After that, review any telemetry error logs for connectivity or data issues. Finally, use debug commands to capture real-time telemetry packets.