CLCOR Practice Test 12 — 15 Questions

Question 1

A company is deploying Webex Hybrid Video Mesh to optimize media traversal for internal meetings. The administrator has deployed two Video Mesh nodes in a cluster. During testing, users on the internal network report poor video quality when joining meetings hosted by the Video Mesh nodes, while external users have good quality. What is the most likely cause?

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

Accepted Answer

The internal clients cannot reach the Video Mesh nodes due to firewall or routing issues.. For Video Mesh to improve media quality, internal clients must have direct IP connectivity to the Video Mesh nodes. If firewall rules or routing prevent this, clients will use the Webex cloud for media, which may result in poor quality. Ensuring that internal clients can reach the Video Mesh nodes on the required ports is essential for optimal performance.

Answer

The Video Mesh nodes are not configured with public IP addresses.

Answer

The Video Mesh cluster is not configured for high availability.

Answer

The Video Mesh nodes are not registered with Cisco Unified Communications Manager.

Question 2

An administrator is configuring Cisco Webex Hybrid Directory Service to synchronize users from an on-premises Active Directory to Webex Control Hub. The synchronization is not working, and the connector status in Control Hub shows 'Not Connected'. What is the most likely cause?

Accepted Answer

The Cisco Directory Connector service is not running or is not properly registered with Webex.. Hybrid Directory Service uses the Cisco Directory Connector installed on a Windows server to synchronize Active Directory users to Webex. If the connector service is stopped or not registered, Control Hub will show 'Not Connected'. Checking the service status and registration is the first step to resolve synchronization issues.

Answer

The Expressway-C certificate has expired.

Answer

The Active Directory domain controller is not reachable from the Expressway-C.

Answer

The Webex Control Hub administrator account does not have the 'Directory Synchronization' role.

Question 3

A CUBE is configured to route calls between Cisco Unified Communications Manager and a SIP provider. The provider sends calls with a '+1' prefix, but the internal dial plan expects calls without the '+'. Which CUBE feature should be used to strip the '+' from the incoming called number before extending the call to Unified CM?

Accepted Answer

voice translation-profile. To strip the '+' prefix from the incoming called number, you should use a voice translation-profile with a translation rule that matches the '+' and removes it. Apply this profile to the inbound dial-peer from the provider. This modifies the called number before the call is routed to Unified CM, ensuring compatibility with the internal dial plan.

Answer

dial-peer destination-pattern with 'no +'

Answer

voice-class uri

Answer

SIP normalization script

Question 4

A collaboration engineer is deploying a new Cisco Webex Room Kit Pro in a conference room. The device is registered to Cisco Unified Communications Manager (CUCM) using SIP. The engineer needs to ensure that the device can place calls to external numbers and that the dialed digits are correctly processed. Which two configuration elements must be defined on CUCM to enable external dialing from this endpoint? (Choose two.)

Accepted Answer

Route Pattern. To enable external dialing from a Cisco Webex Room Kit Pro registered to CUCM, you must configure a Route Pattern to match the dialed digits and route the call, and a Gateway or Route List to provide the physical connection to the external network. The Route Pattern directs the call to the Route List, which then selects a Gateway. Without these, the call cannot leave the CUCM cluster.

Answer

SIP Profile with Outbound Proxy

Answer

Device Pool with Region settings

Answer

Translation Pattern

Question 5

A Cisco Unified Communications Manager (CUCM) administrator is configuring a new phone for a user. The user needs to be able to dial internal extensions, local PSTN numbers, and international numbers. The administrator has created a device pool, a line, and a directory number. Which additional configuration is required to allow the phone to place calls to the PSTN?

Accepted Answer

Assign a calling search space to the phone's directory number that includes the partitions containing the route patterns for PSTN access.. In CUCM, call permissions are enforced through calling search spaces (CSS) and partitions. The CSS assigned to the directory number determines which partitions (and thus which route patterns) the phone can access. To allow PSTN calls, the CSS must include the partitions containing the relevant route patterns. This is the essential configuration step.

Answer

Add the phone to a device pool that contains the gateway for PSTN connectivity.

Answer

Configure a translation pattern that converts internal extensions to E.164 format for all outbound calls.

Answer

Enable the 'Allow Outbound Calls' checkbox in the phone's configuration page.

Question 6

A collaboration engineer is troubleshooting a one-way audio issue between two Cisco IP Phones registered to the same Cisco Unified Communications Manager cluster. The phones are in different locations separated by a WAN link. The engineer captures traffic and notices that the SIP signaling is correct, but RTP packets are only flowing in one direction. The engineer suspects a NAT or firewall issue. Which protocol or feature should the engineer verify to ensure that RTP can traverse the NAT and firewalls correctly?

Accepted Answer

Interactive Connectivity Establishment (ICE). One-way audio often results from NAT or firewall blocking RTP in one direction. ICE is a protocol that helps endpoints discover and negotiate media paths through NAT by using STUN and TURN. In CUCM, ICE can be enabled on SIP profiles to facilitate NAT traversal. Verifying ICE configuration is the correct step to ensure RTP flows bidirectionally. Other options like Early Offer or MTP do not directly address NAT traversal for media.

Answer

SIP Early Offer

Answer

Media Termination Point (MTP)

Answer

Skinny Client Control Protocol (SCCP)

Question 7

A user dials a number that matches a route pattern configured with the 'Urgent Priority' check box selected. What is the effect of this setting on the dialing behavior?

Accepted Answer

The call is placed immediately without waiting for the interdigit timeout.. The Urgent Priority setting on a route pattern instructs CUCM to route the call immediately when the dialed digits match the pattern, without waiting for the interdigit timeout. This is particularly useful when patterns overlap, such as a pattern for 911 and another for 9.1.1, ensuring emergency calls are placed without delay. It does not affect queuing, pattern order, or busy handling.

Answer

The call is blocked if the destination is busy.

Answer

The call is queued until a gateway becomes available.

Answer

The route pattern is placed at the top of the dial plan for all users.

Question 8

A collaboration engineer is preparing a Cisco Unified Communications Manager cluster for a new site that requires the Cisco 8845 IP Phone to operate in a secure environment. The security team mandates that all signaling and media between the phone and CUCM be encrypted, and that the phone authenticate to CUCM using a locally significant certificate (LSC). Which action must the engineer take first to ensure the phone can obtain an LSC and register securely?

Accepted Answer

Enable 'Mixed Mode' on the CUCM cluster and restart the Cisco CallManager service.. To enable secure signaling and media with LSCs, the CUCM cluster must first be switched to Mixed Mode. This activates the Cisco CTL and allows the CAPF service to issue LSCs to supported endpoints. Only after Mixed Mode is enabled can a Phone Security Profile with Encrypted mode be effective, and the phone can then register securely using its LSC.

Answer

Upload a publicly signed certificate to the CUCM Tomcat trust store and restart the Cisco Tomcat service.

Answer

Configure a Phone Security Profile with 'Device Security Mode' set to Encrypted and assign it to the phone.

Answer

Install a Certificate Authority Proxy Function (CAPF) certificate on the phone manually via the phone's web interface.

Question 9

A collaboration administrator is deploying a new Cisco Unified Communications Manager (CUCM) cluster and needs to ensure that the publisher database is protected against corruption. The administrator plans to use the Disaster Recovery System (DRS) for backups. Which statement accurately describes a DRS backup requirement?

Accepted Answer

DRS requires an external SFTP server to store the backup files, and the backup can include the publisher and all subscribers.. The Disaster Recovery System (DRS) in CUCM uses an external SFTP server to store backups. Backups are scheduled from the publisher and can include the publisher and all subscribers. This ensures that the entire cluster's configuration and data are protected. The SFTP server must be configured with sufficient storage and network access from all nodes.

Answer

A DRS backup can only be restored to a cluster with the exact same IP addresses and hostnames.

Answer

DRS backups must be scheduled on each node individually, and the backup files are stored locally on each node.

Answer

DRS backup is only supported for the publisher node and cannot include subscriber nodes.

Question 10

A collaboration engineer is deploying a new branch where WAN congestion causes jitter on voice calls. The carrier marks all traffic with DSCP 0 on ingress. The engineer wants the branch Cisco IOS router to reclassify voice bearer traffic into the EF class and apply priority queueing before the traffic enters the MPLS WAN. Which configuration approach accomplishes this goal?

Accepted Answer

Configure a class-map matching RTP media ports, then a policy-map that uses the priority command, and apply it outbound on the WAN interface with service-policy output.. Because the carrier resets all packets to DSCP 0, the branch router cannot rely on trust. The engineer must classify voice bearer by RTP port range, mark or treat it as EF, and give it strict-priority queueing with the priority command in a policy-map applied outbound on the WAN interface. This restores low-latency treatment toward the congested MPLS path.

Answer

Configure RSVP between the branch router and the WAN headend to reserve bandwidth for voice bearer traffic.

Answer

Configure the WAN interface with mls qos trust dscp and enable auto-qos on the interface.

Answer

Configure a policy-map with a bandwidth guarantee for voice and apply it inbound on the LAN interface.

Question 11

When deploying Cisco IP phones, what is the best practice for VLAN configuration?

Accepted Answer

Use a dedicated Voice VLAN.. Best practice is to place voice traffic on a dedicated Voice VLAN, separate from the data VLAN, so that QoS policies, security, and broadcast domain boundaries can be applied specifically to voice. This also enables features like voice VLAN access (CDP/LLDP-MED) that let the phone tag its own traffic while the PC behind it uses the data VLAN untagged.

Answer

Use the default VLAN 1 for all voice and data.

Answer

Use a separate physical switch for phones.

Answer

Do not use VLANs; use static routing.

Question 12

Where in Webex Control Hub do you verify the health status of Hybrid Service connectors?

Accepted Answer

Services tab. In Webex Control Hub, the health status of Hybrid Service connectors is verified under the Services tab. Navigating to Services > Hybrid Services (or the specific service like Call/Calendar) shows connector status, registration state, and any alerts for each Expressway-C node running the connector.

Answer

Troubleshooting tab

Answer

Devices tab

Answer

Users tab

Question 13

You are designing a high-availability solution for Cisco Expressway. Which element is required to load-balance traffic between multiple Expressway nodes?

Accepted Answer

External Load Balancer. To load-balance traffic across multiple Expressway nodes (e.g., Expressway-C or Expressway-E clusters), an external load balancer is required because Expressway does not provide built-in load balancing. The load balancer distributes incoming connections across the nodes for scalability and high availability.

Answer

Cisco CUBE redundancy

Answer

Cisco UCM Group

Answer

DNS Round Robin only

Question 14

You are troubleshooting a scenario where internal calls between two offices are using the G.711 codec, but you want them to use G.729 to save bandwidth. Where should you change the codec setting?

Accepted Answer

System > Region Information > Region. In Cisco Unified Communications Manager, codec selection for calls between locations is controlled by regions. Regions define the codec used for calls between devices in different regions. To change the codec between two offices, you modify the region settings (System > Region Information > Region) and set the appropriate codec (e.g., G.729) for the region pair.

Answer

Device > Device Settings > Common Device Configuration

Answer

System > Device Pool

Answer

System > Location

Question 15

You are designing a network for video collaboration. What is the recommended maximum one-way latency for high-quality video conferencing?

Accepted Answer

150ms. For high-quality, interactive video conferencing, the ITU-T G.114 recommendation specifies that one-way latency should not exceed 150 ms to maintain conversational quality. Beyond 150 ms, participants begin to notice talker overlap and difficulty with turn-taking, degrading the collaboration experience. 150 ms is the accepted threshold for real-time voice and video applications.

Answer

300ms

Answer

500ms

Answer

50ms