CLCOR Practice Test 2 — 10 Questions

Question 1

You are deploying Webex Hybrid Data Security (HDS). After deploying the virtual machines for the HDS nodes, you find they are not appearing in Control Hub. What is the first step you should take to troubleshoot the registration?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Check the local log files in the HDS node using the CLI.. When HDS nodes do not appear in Control Hub, the first troubleshooting step is to check the local log files on the HDS node via the CLI. The logs will show whether the node successfully reached the Webex cloud, whether the registration token was accepted, and whether there are certificate or connectivity errors. This is the fastest way to identify the root cause before making configuration changes.

Answer

Disable the firewall on the HDS node.

Answer

Restart the Cisco Webex Hybrid Services host.

Answer

Re-download the management certificate.

Question 2

Which THREE of the following factors impact the quality of video calls in a network?

Accepted Answer

Packet loss. Packet loss (A) is correct because dropped RTP/UDP packets in a video stream cause visible artifacts, freezing, and audio gaps, directly degrading call quality. Jitter (C) is correct because variation in packet inter-arrival times disrupts the playout buffer, causing choppy audio and stuttering video even when average delay is acceptable. Latency (E) is correct because high end-to-end delay (typically above 150 ms one-way) impairs interactivity and, combined with jitter and loss, degrades the real-time experience. Interface description (B) is only a text label on an interface and has no effect on traffic handling, and router uptime (D) is an availability metric that does not by itself determine video quality as long as the device is forwarding packets.

Answer

Interface description

Answer

Router uptime

Question 3

You are configuring a Cisco IOS XE voice gateway to register with an ITSP over SIP. The provider requires registration to be refreshed every 60 seconds. You have already configured the registrar and credentials under sip-ua. Which command correctly sets the registration expiry timer to 60 seconds?

Accepted Answer

timers expires 60. The registration expiry timer on a Cisco IOS XE voice gateway is configured under sip-ua with the timers expires command. This timer determines how often the gateway sends a REGISTER refresh to the SIP registrar. Setting it to 60 seconds aligns with the provider's requirement for a 60-second refresh interval, preventing the registration from expiring unexpectedly.

Answer

authentication username user password pass

Answer

registrar ipv4:10.1.1.1 expires 60

Answer

retry invite 3

Question 4

You are configuring a local gateway for Webex Calling. Which mechanism ensures that the Webex Cloud can communicate with your on-premises edge device without requiring inbound firewall ports?

Accepted Answer

Outbound TLS connection from CUBE to Webex Cloud. Webex Calling uses a persistent outbound TLS connection from the on-premises CUBE (Customer Edge) to the Webex Cloud. This connection is initiated from the enterprise side, typically over TCP port 8934 (or 443 for some services), and is kept alive with keepalives. Because the connection is outbound, no inbound firewall ports need to be opened, and the cloud can send messages back over the established TLS session. This design is fundamental to Webex Calling's cloud-to-edge architecture, ensuring secure and NAT-friendly connectivity.

Answer

Webex Calling Connector via port forwarding

Answer

SIP Trunk over VPN

Answer

H.323 Gatekeeper registration

Question 5

Which dashboard in Control Hub provides insights into the quality and usage of hybrid services?

Accepted Answer

Analytics Dashboard. The Analytics Dashboard in Control Hub provides insights into quality and usage of hybrid services, including call quality, media statistics, and service adoption. It aggregates data from hybrid connectors and services to show trends and performance. This is the designated dashboard for hybrid service analytics.

Answer

Device Dashboard

Answer

Troubleshooting Dashboard

Answer

Management Dashboard

Question 6

Which protocol provides the signaling for Webex Room devices when they are registered to CUCM (on-premises)?

Accepted Answer

SIP. Webex Room devices, when registered on-premises to CUCM, use SIP (Session Initiation Protocol) for signaling. SIP is the standard protocol for establishing, modifying, and terminating multimedia sessions, and it is supported by Webex devices for call control with CUCM.

Answer

MGCP

Answer

SCCP

Answer

H.323

Question 7

A network engineer is configuring a Cisco IOS router to mark voice bearer traffic with the DSCP value EF (46) and call signaling traffic with CS3 (24). The engineer wants to ensure that both marking operations are applied in a single policy-map on the ingress interface. Which configuration element is required to differentiate the two traffic classes before marking?

Accepted Answer

A class-map that matches voice bearer and signaling using ACLs or protocol-specific match criteria.. The correct approach is to create a class-map that identifies voice bearer and signaling traffic based on protocol and port numbers, then reference that class-map in a policy-map where DSCP values are set. This ensures that both traffic types are properly marked regardless of their initial markings. Using ACLs or protocol-specific match criteria allows precise differentiation, which is essential for downstream QoS treatment.

Answer

A class-map that matches on IP precedence 5 for voice and 3 for signaling.

Answer

A policy-map that uses the 'set ip dscp' command with a table-map to translate incoming markings.

Answer

A route-map that matches on RTP and SIP ports and sets the DSCP values.

Question 8

When designing for high availability of Cisco Unified Communications Manager (CUCM) services, which specific configuration ensures that a secondary node takes over call processing if the primary node fails?

Accepted Answer

Configure a CUCM Group in the Device Pool with multiple servers.. A CUCM Group is an ordered list of up to three CUCM servers (primary, secondary, tertiary) that a device uses for call processing. When you assign a CUCM Group to a Device Pool, every device referencing that pool will attempt registration with the first server in the list and, if it becomes unreachable, will fail over to the next server in the group. This is the standard, supported mechanism for call-processing redundancy in a CUCM cluster.

Answer

Set the 'Call Processing Load' value in the System settings.

Answer

Enable Auto-registration for all phones.

Answer

Configure the cluster-wide failover parameter in the Service Parameter page.

Question 9

You are troubleshooting intermittent audio quality. You notice that RTCP packets are arriving with high variance. What does this indicate?

Accepted Answer

Jitter. RTCP (RTP Control Protocol) provides reception quality feedback, including interarrival jitter, which is the statistical variance in packet arrival times. High variance in RTCP-reported jitter indicates network jitter — packets are arriving with uneven spacing, causing audio quality issues like choppy or robotic voice. Jitter is distinct from latency (delay) and packet loss (missing packets).

Answer

Latency

Answer

Codec Mismatch

Answer

Packet Loss

Question 10

When troubleshooting CUBE SIP normalization, which tool allows you to view the normalized SIP messages in real-time?

Accepted Answer

debug ccsip messages. The command `debug ccsip messages` (B) enables real-time debugging of SIP messages on Cisco Unified Border Element (CUBE). It displays the actual SIP messages sent and received, including the normalized messages after SIP normalization profiles are applied, allowing you to verify the normalization logic.

Answer

show voice class sip-profiles

Answer

debug voip ccapi inout

Answer

debug sip-ua

Answer

show sip-profile