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troubleshooting

Practise Cisco Implementing Cisco Collaboration Core Technologies (CLCOR, 350-801, v2.0 blueprint, CCNP Collaboration) (CLCOR) troubleshooting practice questions — original exam-style scenarios with answer choices, explanations, and analysis of common mistakes.

259 questions65 easy117 medium77 hard

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What to know about troubleshooting

troubleshooting questions test whether you can apply the concept in context, not just recognise a definition.

How the topic appears in realistic exam-style scenarios.

Which detail in the question changes the correct answer.

How to eliminate plausible but wrong options.

How to connect the question back to the wider exam objective.

Watch out for

Common troubleshooting exam traps

  • ▸Answering from memory before reading the full scenario.
  • ▸Missing a constraint such as cost, availability, security, scope or command context.
  • ▸Choosing a broad answer when the question asks for the most specific fix.
  • ▸Ignoring why the wrong options are tempting.

Question index

All troubleshooting questions (259)

Click any question to see the full explanation, or start a practice session above.

1

A Cisco Unified Communications Manager (CUCM) cluster is configured with a SIP trunk to a Cisco Unified Border Element (CUBE) for PSTN connectivity. Users report that outbound calls to a specific area code fail, but all other calls succeed. The CUCM route pattern for that area code is configured with a route list that includes the SIP trunk. The CUBE shows that it receives the INVITE but rejects it with a 488 Not Acceptable Here. Which CUCM configuration should be checked first to resolve this issue?

Hard
2

Which TWO of the following are valid methods for providing high availability for IP phones in a CUCM design?

Medium
3

What is the first step to enable Webex Hybrid Services in a new organization?

Easy
4

Which deployment model should be chosen for Cloud Connected PSTN (CCP) if the organization wants to leverage their existing carrier contracts?

Medium
5

A Cisco IOS gateway is connected to a WAN circuit where the physical line rate is 10 Mbps but the contracted CIR is only 4 Mbps. Voice quality suffers during bursts because the provider polices traffic above the CIR and drops excess packets. The engineer wants the gateway to smooth outbound traffic so the provider does not discard bursts. Which configuration element should be applied to the WAN interface?

Hard
6

Which TWO of the following are valid deployment models for the Webex Calling PSTN connectivity? (Choose two)

Medium
7

A network administrator is troubleshooting one-way audio issues between a Cisco IP Phone and a Cisco TelePresence endpoint. The path traverses a router with a configured class-map. Which command would you use to verify the packet markings on the ingress interface?

Medium
8

Which service must be running for a phone to receive its configuration file?

Easy
9

A network engineer is deploying a new branch office with a Cisco IOS XE gateway that connects to the service provider via a 100-Mbps Ethernet WAN link. The engineer needs to ensure that interactive voice traffic always receives priority treatment during congestion, while preventing non-real-time traffic from being starved. Which QoS mechanism should be configured on the WAN interface to guarantee strict priority for voice while still servicing other queues?

Medium
10

You are troubleshooting a scenario where internal calls between two sites are failing. The call fails immediately when dialed. What is the most effective way to verify that the Calling Search Space (CSS) has access to the destination partition?

Medium
11

A collaboration designer must ensure that inter-cluster calls between two CUCM clusters remain secure. Which mechanism must be implemented to ensure media remains encrypted from end to end?

Hard
12

Which network condition is the most significant contributor to poor voice quality in a VoIP environment?

Easy
13

You have a requirement to use secure signaling for SIP endpoints. Which protocol and port combination must be used in the SIP Security Profile?

Hard
14

In the context of collaboration design, what is the purpose of the 'Location' in CUCM?

Easy
15

An administrator needs to verify that the Webex Hybrid Calendar Service connector is running and healthy. Where in Webex Control Hub should the administrator check the status of the connector?

Easy
16

You have a cluster with multiple nodes. You want to ensure that phones in the 'New York' office prioritize registration to a 'New York' subscriber. How do you implement this?

Hard
17

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

Medium
18

A collaboration engineer is designing QoS for a Cisco Collaboration deployment where IP phones connect to Cisco Catalyst switches and the WAN edge is a Cisco IOS XE router. The engineer wants to ensure that voice bearer traffic is properly marked and prioritized end to end. Which two actions should the engineer take to establish a consistent QoS trust boundary? (Choose two.)

Medium
19

Which TWO of the following are valid types of Media Resources in CUCM?

Medium
20

What is the primary function of the Cisco Webex Edge Audio service?

Medium
21

You need to enforce a specific codec for calls traversing a CUBE. Where is the most appropriate place to apply this configuration?

Medium
22

What happens to a user's Webex account if they are removed from the synchronized Active Directory group?

Medium
23

Which field in a Route Pattern can be used to discard the first few digits of a dialed number before routing?

Medium
24

You need to ensure that the Webex App can perform 'Click-to-Call' from a browser. What must be installed on the user's machine?

Hard
25

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?

Medium
26

What is the function of 'Cisco Unified Reporting' in a CUCM environment?

Medium
27

A Cisco Unified CM cluster is configured with a SIP trunk to a Cisco Unified Border Element (CUBE). Calls from the PSTN arrive at CUBE and are sent to CUCM. The ITSP requires that the From header contain the original calling number in E.164 format, but CUCM is sending it in a 10-digit national format. You need to ensure the From header is rewritten to include the +1 prefix. Which configuration on CUCM will accomplish this?

Hard
28

When configuring a Device Pool in CUCM, which parameter is responsible for defining the set of codecs used between devices in different regions?

Easy
29

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

Hard
30

When a SIP phone initiates a call, which message does the CUCM send to acknowledge the initial INVITE?

Medium
31

A collaboration engineer is implementing a dial plan that requires all calls to emergency services (911) to be routed over a specific SIP trunk to a dedicated PSAP gateway, regardless of the calling device's location. Which CUCM configuration element should be used to ensure this routing?

Hard
32

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?

Medium
33

Where do you configure the time zone for a specific set of devices, such as those in a specific branch office?

Easy
34

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

Easy
35

An engineer needs to verify the current active calls on a Cisco IOS XE voice gateway and see details such as call legs, codecs, and durations. Which command should be used?

Easy
36

You are migrating to a new SIP provider. You have a requirement to use 'Early Offer' for all calls on this trunk. Where is this configured?

Hard
37

A company is deploying Webex Hybrid Data Security (HDS) to enhance privacy for Webex messages and files. Which two components must be deployed on-premises to support this service? (Choose two.)

Hard
38

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?

Medium
39

Which of the following is a key advantage of utilizing Cloud Connected PSTN (CCP)?

Easy
40

Which CUCM service must be activated in Serviceability to allow for the use of the 'Cisco Extension Mobility' feature?

Easy
41

When using Webex Calling with the Local Gateway, which protocol is used for the SIP trunk between the CUBE and the Webex Calling cloud?

Medium
42

You need to ensure that the Webex Hybrid Calendar service can access an Exchange 2019 environment. Which authentication method is recommended by Cisco for this deployment?

Medium
43

What is the primary function of a 'Location' object in CUCM?

Medium
44

A company is deploying a centralized Cisco Unified Communications Manager (CUCM) cluster with a single publisher and two subscribers. The publisher is located in the data center, and the subscribers are in the same data center. Branch offices connect via a WAN. The design team wants to ensure that IP phones at the branches can register and make calls even if the WAN link fails. Which CUCM feature should be implemented to achieve this?

Medium
45

Which configuration in Control Hub allows you to define the emergency address for a user in a Webex Calling environment?

Medium
46

You have a requirement to play a custom announcement when a call is placed on hold. Where do you configure this?

Medium
47

Which file does an IP phone download first to obtain its configuration from the TFTP server?

Easy
48

A company is deploying Cisco Unified Communications Manager in a centralized call processing model with remote branches connected via a WAN. The network team wants to ensure that if the WAN link fails, IP phones at the branch can still make calls to the PSTN. Which solution should be implemented at the branch?

Easy
49

In a multi-site deployment, you have a requirement to transcode between G.711 and G.729. If the transcoder resources are exhausted, what is the expected outcome for a new call requiring this conversion?

Hard
50

Which design principle must be followed when implementing a centralized call processing deployment with remote branch offices connected via a WAN?

Medium
51

A Cisco Unified CM administrator is troubleshooting a call that fails with a 'No Route to Destination' cause code. The called number is 2001, which is an internal extension on a remote cluster. The local cluster has a SIP trunk to the remote cluster and a route pattern of 2XXX pointing to that trunk. The SIP trunk is up, but the call fails. What is the most likely cause?

Hard
52

Where do you define the default dial plan for a new CUCM cluster?

Easy
53

Which service must be active for CTI applications (like Cisco Finesse) to control phones?

Medium
54

A network engineer is troubleshooting a Cisco IP Phone 7841 that fails to register with CUCM. The phone displays 'Configuring IP' and then 'Registering'. The engineer verifies that the phone has obtained an IP address and can ping the TFTP server. Which protocol does the phone use to download its configuration file from the TFTP server?

Easy
55

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?

Easy
56

When designing a secure collaboration network, what is the best practice for handling certificates in a CUCM and Expressway cluster?

Hard
57

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?

Easy
58

A branch office has a limited bandwidth link. You need to ensure that no more than 5 calls can be made across the WAN at once. What should you configure?

Hard
59

When using 'RSVP' for Call Admission Control (CAC), what happens if the available bandwidth on the path is less than the requested amount?

Medium
60

Which TWO of the following media resource types are supported in CUCM?

Medium
61

A company has deployed Cisco Webex Hybrid Calendar Service with Exchange 2019 on-premises. Users report that scheduled Webex meetings are not appearing on their calendars, and the connector shows a 'Connected' status but no calendar events are being processed. Which action should be taken to resolve this issue?

Hard
62

A network administrator is configuring QoS on a Cisco IOS router for a collaboration deployment. The administrator needs to ensure that voice control traffic, such as H.225 and H.245 signaling, is marked with the appropriate DSCP value. According to Cisco best practices, which DSCP value should be used for call signaling traffic?

Easy
63

A Cisco Unified Communications Manager cluster is using a SIP trunk to an ITSP. The ITSP sends calls to the enterprise with a +1 prefix, but the enterprise dial plan uses 10-digit numbers without the country code. You need to strip the +1 from the incoming calling and called numbers before they are presented to the dial plan. Where should you configure this translation?

Medium
64

You are implementing a QoS policy on a WAN edge router. You have a requirement to prioritize video traffic. Which queueing mechanism is recommended by Cisco to minimize jitter and latency for video streams?

Hard
65

You are configuring a Cisco IOS XE voice gateway to route inbound SIP calls to different dial peers based on the Request-URI domain. You want to match calls destined to 'example.com' to a specific dial peer. Which configuration element should you use to achieve this?

Medium
66

Which component is required to synchronize users from an on-premises Active Directory to the Webex Cloud?

Easy
67

You are designing a Cisco Unified Communications Manager (CUCM) dial plan for a multinational company. The company has offices in North America, Europe, and Asia. Each region has its own PSTN gateway and dial plan requirements. The customer wants to minimize dial plan complexity and ensure that users can dial local numbers as they are accustomed to. Which approach should you recommend?

Hard
68

Which TWO of the following are valid components of a Cisco IOS voice gateway configuration?

Easy
69

A collaboration engineer is designing a CUCM cluster with two nodes: a publisher and a subscriber. The engineer must ensure that the cluster can support 2500 IP phones and that call processing continues if the publisher fails. Which statement accurately describes the design requirement?

Hard
70

You are troubleshooting a scenario where G.711 is being used instead of the expected Opus codec between two endpoints in the same region. What is the most likely cause in the CUCM configuration?

Medium
71

A user reports that their calls are failing when they roam to a different physical office site. You observe that the device is registered to the primary CUCM cluster but the Location-based CAC is blocking the call. What is the most likely cause?

Hard
72

Which component in the CUCM dial plan allows you to match a pattern and simultaneously transform it into a new number before the final route lookup?

Medium
73

A network designer is planning a centralized call processing deployment with 20 remote sites. Each site has 50 IP phones and uses G.711 for internal calls. The designer must ensure that calls between sites use G.729 to conserve WAN bandwidth, but calls within a site use G.711. Which CUCM configuration element should be used to achieve this?

Hard
74

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?

Hard
75

Which feature allows you to group multiple gateways and route lists to provide load balancing and failover for outbound calls?

Medium
76

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

Hard
77

You are troubleshooting a registration issue where the phone sends a REGISTER request, but the server does not respond. What is the most likely issue?

Medium
78

A collaboration administrator needs to provide users with the ability to make and receive PSTN calls through Webex Calling without deploying any on-premises gateways or maintaining a separate carrier contract. Which Webex Calling PSTN option should the administrator choose?

Easy
79

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?

Medium
80

Which TWO of the following describe the purpose of the Webex Edge for Devices service?

Medium
81

What is the primary difference between a 'Route Pattern' and a 'Translation Pattern'?

Hard
82

You are deploying CUBE. Which command enables the CUBE functionality on the Cisco IOS XE router?

Easy
83

When configuring CUBE, why would you use a 'voice class uri' command?

Medium
84

Which THREE items are required to successfully register a room device to Webex?

Hard
85

You are observing that video traffic is marked as DSCP 0. How can you fix this at the network level without changing the endpoint configuration?

Medium
86

Which TWO features are provided by the Cisco Webex App when registered as a Softphone?

Easy
87

In CUCM, what is the purpose of the 'Calling Search Space' (CSS)?

Easy
88

You are implementing a centralized dial plan. You have multiple sites, each with local PSTN gateways. How can you ensure that an emergency call from a specific site is always routed to the local PSTN gateway of that site?

Hard
89

A user reports that when they dial an internal extension, they hear a fast busy tone. The administrator checks the dialed number and confirms it exists in the CUCM database. Which configuration element should the administrator verify first to resolve the fast busy tone?

Easy
90

A company uses Webex Hybrid Calendar Service. Users report that the 'Join' button is missing from their Webex Room devices for scheduled meetings. What is the most likely cause?

Hard
91

You need to migrate users from an on-premises Cisco Unified Communications Manager (CUCM) to Webex Calling. Which tool allows for the bulk onboarding of users while maintaining existing directory synchronization?

Medium
92

What is the primary function of a dial-peer destination-pattern?

Medium
93

A company is deploying Webex Hybrid Directory Service to synchronize on-premises Active Directory users to Webex Control Hub. The administrator has installed the connector on a Windows Server 2019 machine and configured the required DNS SRV record. During the connector setup, the administrator is prompted to provide credentials for a service account. Which of the following must be true about this service account?

Medium
94

A collaboration engineer is configuring Webex Hybrid Call Service Connect to integrate an on-premises Cisco Unified Communications Manager (CUCM) cluster with Webex. The engineer has deployed Expressway-C and Expressway-E in the enterprise and has enabled the Hybrid Call Service Connector on the Expressway-C. After configuration, users in Webex Teams cannot place calls to on-premises CUCM-registered endpoints. Which of the following is the most likely cause?

Hard
95

A Cisco IOS XE gateway is configured with two POTS dial peers that both match an inbound PSTN call on voice port 0/0/0. The first dial peer has preference 1 and destination pattern 9T; the second has preference 2 and destination pattern 9.... An engineer notices that calls are always routed using the second dial peer. What is the most likely explanation?

Medium
96

An endpoint sends a SIP REGISTER request. CUCM returns a 401 Unauthorized response. What is the next logical step in the SIP signaling flow for the endpoint?

Hard
97

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

Medium
98

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

Easy
99

What is the primary function of the CUBE in a SIP trunking scenario?

Medium
100

When a call is made to a destination that matches multiple partitions in a user's CSS, how does CUCM determine which pattern to use?

Medium
101

A user reports that they cannot hold an active call when the Media Resource Group List (MRGL) is configured with a specific Transcoder. The CUCM trace shows 'Allocation Failure'. What is the most likely cause?

Hard
102

Which THREE of the following are necessary to ensure successful NTP deployment in a CUCM cluster?

Hard
103

A Cisco IP Phone 8845 in the New York office registers to CUCM and downloads its configuration. The administrator notices that the phone uses a DHCP scope option to discover the TFTP server address. Which DHCP option is used by the phone for this purpose?

Medium
104

Which THREE of the following are key features provided by a QoS policy-map?

Hard
105

Which TWO of the following are essential components of a Cisco network readiness assessment for collaboration?

Medium
106

Which license type is required to manage Webex Calling services in Control Hub?

Easy
107

What is the function of a 'Device Pool' in CUCM?

Easy
108

Which THREE types of media resources can be managed by an MRGL?

Easy
109

Which THREE of the following tasks are required to set up a basic SIP trunk in CUCM?

Hard
110

A collaboration engineer is designing a Cisco Unified Communications Manager (CUCM) cluster for a company with 5000 users. The cluster will have one publisher and three subscribers. The engineer must ensure that the design supports high availability and that IP phones can register and make calls even if one subscriber fails. Which two statements are true regarding CUCM redundancy and device registration? (Choose two.)

Medium
111

You are configuring a Webex Calling environment for a customer that requires integration with an existing on-premises PBX using a Cisco Unified Border Element (CUBE). Which gateway type should you register to Webex Control Hub to enable this connectivity?

Medium
112

A user reports that when they dial an internal extension, they hear a fast busy tone. The administrator checks the CUCM configuration and finds that the user's phone is registered and the dialed extension exists. Which CUCM component is responsible for determining that the dialed digits are a valid internal extension and routing the call?

Easy
113

You are deploying Webex Calling with Local Gateway. Which component must be configured to allow PSTN connectivity for users who have migrated from on-premises CUCM to the cloud?

Medium
114

If a Translation Pattern is configured in CUCM, at what stage of the call processing does the digit manipulation occur?

Medium
115

A Cisco CUBE is deployed to connect a Cisco Unified Communications Manager (CUCM) cluster to a service provider SIP trunk. The service provider requires that all outgoing SIP INVITE messages contain a specific custom header, X-Provider-ID, with a value of 'CUBE123'. Which CUBE configuration is required to insert this header into outgoing INVITEs?

Medium
116

An administrator needs to restrict a group of phones from making long-distance calls. Which component of the CUCM dial plan should be modified to achieve this while maintaining internal dialing?

Hard
117

A collaboration engineer is configuring a Webex Calling PSTN option where the enterprise wants to keep its existing Cisco Unified Border Element (CUBE) and SIP trunk contract with the incumbent carrier, while still using Webex Calling for call control and user features. Which Webex Calling PSTN connection type should the engineer select in Webex Control Hub?

Medium
118

A collaboration engineer is designing a SIP trunk between Cisco Unified Communications Manager (CUCM) and Cisco Unified Border Element (CUBE). The engineer must ensure that calls are routed correctly and that CUCM can send calls to CUBE. Which element should be configured on CUCM to point to CUBE as the next hop for calls destined to the ITSP?

Hard
119

You are configuring a Cisco IOS router to perform traffic shaping for voice traffic. Why is traffic shaping often used in conjunction with queuing?

Hard
120

Which service allows Webex users to see the presence status of an on-premises Jabber user?

Medium
121

Which tool can be used to perform a bulk import of users and devices into CUCM?

Medium
122

When designing an NTP deployment for a Cisco Collaboration environment, what is the best practice for time synchronization across CUCM nodes?

Easy
123

Which menu path in CUCM Administration is used to configure the 'Cisco Unified Communications Manager Group'?

Easy
124

A network engineer is configuring a Cisco IOS router to classify traffic for a QoS policy. The engineer needs to identify packets based on the DSCP value EF that has already been marked by an upstream IP phone. Which configuration element should be used to match this traffic?

Easy
125

A collaboration engineer is designing a Webex Hybrid Services deployment for an organization that requires all media to be processed on-premises while still using Webex Control Hub for user management and analytics. The organization has an existing Expressway-C and Expressway-E pair. Which Webex Hybrid service must be deployed to meet the requirement that all call signaling and media remain on-premises?

Medium
126

Which component in a Cisco Collaboration design is responsible for providing the dial tone and call routing logic for IP phones?

Easy
127

When configuring an IP phone for automatic provisioning, which DHCP option is most commonly used to provide the TFTP server address to the phone?

Easy
128

A collaboration engineer is designing a Webex Calling deployment for a company that requires all PSTN calls to egress through their existing on-premises Cisco Unified Border Element (CUBE) with a PRI circuit. The company wants to keep the PSTN gateway on-premises and use Webex Calling for internal and external calling. Which deployment option should the engineer choose?

Medium
129

Which THREE of the following are valid reasons to use a Media Termination Point (MTP)?

Hard
130

You are troubleshooting a one-way audio issue. The phone can register, but no audio is heard. What should you check first?

Hard
131

Which feature in CUCM is used to block calls when the available bandwidth in a location is exceeded?

Medium
132

When deploying Webex Hybrid Services, what is the purpose of the Expressway-C cluster?

Medium
133

You have implemented 'Local Route Group' in your dial plan. What is the main advantage of using this instead of static Route Groups?

Hard
134

Which TWO of the following are common audio codecs used in Cisco collaboration?

Easy
135

You are implementing a 'Call Hunt' sequence. You want to ensure that if no agent answers within 20 seconds, the call moves to the next member in the list. Which configuration object manages this timer?

Medium
136

An administrator needs to enforce a bandwidth limit for video calls at a specific site in CUCM. Which configuration object should be used?

Hard
137

Which TWO of the following are true regarding the use of voice translation-rules?

Medium
138

Which statement best describes the difference between policing and shaping?

Hard
139

Which command is used to configure the IP address or hostname of the destination device on a dial-peer?

Easy
140

Which TWO of the following fields are required when defining a Route Pattern?

Medium
141

When adding a new phone, what is the 'Device Name' parameter based on by default?

Easy
142

A Cisco IP Phone 8845 registered to CUCM is not receiving its configuration file from the TFTP server after a factory reset. The phone has received its IP address via DHCP and can ping the TFTP server. Which option in the DHCP scope must be configured to allow the phone to locate the TFTP server?

Medium
143

You are configuring Webex Hybrid Message Service. What is the primary purpose of this service?

Medium
144

What is the result of applying 'voice translation-profile' to an incoming dial-peer?

Medium
145

A user is unable to use their 'Speed Dial' button. What is the first thing you should verify?

Hard
146

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?

Medium
147

When troubleshooting Webex Calling, which THREE factors are critical for maintaining call quality over a hybrid network?

Hard
148

You are integrating an external voicemail system with CUCM. Which object is used to define the dialable number that users call to reach their voicemail box?

Hard
149

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

Easy
150

A Cisco IOS XE gateway is failing to route calls because the dial-peer is not matching the incoming call. Which command helps you identify the dial-peer that matched the incoming call?

Medium
151

You are configuring QoS for a Cisco Unified Communications Manager (CUCM) deployment. You need to ensure that audio media traffic between endpoints is marked correctly. Which DSCP value should be assigned to RTP audio traffic according to the Cisco SRND best practices?

Medium
152

You are designing a Cisco Collaboration deployment for a hospital where 911 calls must always be routed to the nearest Public Safety Answering Point (PSAP) based on the physical location of the calling device. The hospital has multiple buildings across a campus, and wireless IP phones (Cisco 8821) are used by nurses who roam between buildings. Which CUCM feature should you implement to ensure that emergency calls are routed with the correct location information?

Medium
153

A user's Cisco IP Phone 8841 is registered to Cisco Unified Communications Manager but cannot place calls to any internal or external numbers. The phone displays 'Registration Complete' but every call attempt results in a fast busy tone. Which configuration element is most likely missing or misconfigured for this phone?

Easy
154

What is the primary function of a 'Class Map' in a Cisco IOS QoS configuration?

Easy
155

Which service must be running for a Cisco IP Phone to download its configuration file via TFTP?

Medium
156

You need to implement redundancy for a remote site using Survivable Remote Site Telephony (SRST). Which parameter in the Device Pool ensures that the phones fail over to the local router during a CUCM WAN outage?

Hard
157

Which object acts as the primary container for a specific set of users in CUCM?

Easy
158

A collaboration administrator needs to verify that the Webex Hybrid Services connectors are healthy and operational. Where in Cisco Webex Control Hub can the administrator check the status of the connectors?

Easy
159

An administrator configures a Translation Pattern of 9XXX in partition INTERNAL_PT with Calling Search Space ROUTE_CSS. A user in partition USER_PT with CSS ROUTE_CSS dials 8001. The Translation Pattern is fully matched, and its Called Party Transformation CSS is set to TRANSFORM_CSS. Which calling search space is used to search for the final translated pattern after the digit transformation is applied?

Hard
160

An administrator is troubleshooting a failed Hybrid Calendar setup. The 'Connector' shows as 'Down' in Control Hub. What is the most likely reason?

Hard
161

Which protocol is primarily used for the transmission of real-time voice and video data between two endpoints?

Easy
162

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?

Easy
163

Which THREE components are part of the CUCM redundancy architecture?

Easy
164

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?

Medium
165

What is the default behavior for DSCP markings on traffic originating from a Cisco IP Phone that has not been configured with specific QoS policies?

Easy
166

A CUBE is receiving calls but rejecting them due to '488 Not Acceptable Here'. What is the most likely reason?

Hard
167

In a multisite WAN deployment, which codec should you choose to balance voice quality and bandwidth consumption across a constrained link?

Easy
168

You need to prevent certain internal users from making international calls while allowing them to dial local numbers. What is the most efficient way to implement this in CUCM?

Hard
169

A network engineer is deploying Cisco Unified Border Element (CUBE) and must ensure that voice traffic is prioritized correctly across the enterprise network. Which command correctly maps the voice traffic DSCP value to the correct priority queue in a Cisco IOS-XE router?

Medium
170

A collaboration engineer is deploying Webex Hybrid Calling with Cisco Unified Communications Manager (CUCM) as the call control. The engineer wants to provide PSTN access to Webex Calling users by leveraging the existing on-premises Cisco IOS Voice Gateway. Which solution should be implemented?

Medium
171

An engineer is troubleshooting one-way audio for calls traversing a Cisco IOS XE router with NAT between an internal CUCM cluster and an external SIP provider. Signaling completes, but RTP from the provider never reaches the internal phone. The engineer confirms the provider is sending media to the signaling address. Which technology should be enabled on the router to allow the correct media address to be signaled to the provider?

Hard
172

Which DSCP value is recommended for Call Signaling traffic in a Cisco Unified Communications network?

Easy
173

Which TWO of the following are valid methods to handle digit manipulation in CUCM?

Medium
174

A network administrator is troubleshooting poor voice quality on a Cisco Unified Communications Manager cluster. The administrator suspects that the issue is related to the Differentiated Services Code Point (DSCP) value being used for voice bearer traffic. Which DSCP value is recommended by Cisco for voice bearer traffic to ensure it receives priority treatment in the network?

Easy
175

A Cisco Unified Border Element (CUBE) is deployed between Cisco Unified Communications Manager (CUCM) and a SIP service provider. The provider sends an INVITE with a Diversion header containing a redirecting number. The CUBE must pass the redirecting number to CUCM in the History-Info header instead of the Diversion header. Which SIP profile configuration on CUBE accomplishes this?

Hard
176

Which component allows for automatic rerouting of a call if the primary gateway is busy or unreachable?

Medium
177

Which THREE of the following are recommended steps when designing a secure signaling path between CUCM and a CUBE gateway?

Hard
178

Which TWO features are managed by the 'Cisco Unified Serviceability' tool?

Medium
179

A network engineer is deploying a Cisco Unified Border Element (CUBE) for a SIP trunk to an ITSP. The ITSP requires that all outbound calls present a specific calling number and that the SIP From header contain the same number. The engineer must ensure that the calling number is manipulated correctly on the outbound dial peer. Which CUBE configuration command should be used to modify the calling number in both the From header and the P-Asserted-Identity header?

Hard
180

You are managing a Cisco Collaboration cluster and notice that database replication is stuck in a '3' (blocked) state. What is the standard troubleshooting step?

Hard
181

When using 'Call Pickup', how does a user pick up a call that is ringing on another phone in the same pickup group?

Hard
182

A network administrator is configuring a Cisco IP Phone 7811 to register with Cisco Unified Communications Manager. The phone is powered on and connected to the network. The administrator notices that the phone is not obtaining an IP address. Which protocol is responsible for providing the phone with an IP address and other network parameters?

Easy
183

A user complains that they cannot see the 'Transfer' softkey on their phone during an active call. Where is the most appropriate place to check the softkey configuration?

Medium
184

A Cisco IOS XE gateway is configured with a POTS dial-peer that forwards calls to a PRI interface. Users report that inbound PSTN calls are being rejected with a cause code indicating that all circuits are busy, even though the PRI shows no active calls. Which command should you use to verify that the POTS dial-peer is matching the inbound calls correctly?

Medium
185

What is the default behavior of CUCM when a phone is moved to a new site and registers with the local CUCM node, but the Device Pool is not updated?

Easy
186

What is the impact of removing a node from a Hybrid Video Mesh cluster that is currently hosting active meetings?

Medium
187

You are deploying a Webex Room device in a hybrid environment. What is the benefit of registering it to Webex instead of on-premises CUCM?

Medium
188

What is the purpose of the 'Common Device Configuration' in CUCM?

Medium
189

When managing Webex Calling using the 'Webex Calling' app versus the 'Webex' app, what determines the calling capabilities?

Medium
190

A collaboration engineer is deploying a new branch office with Cisco Unified Communications Manager and wants to ensure that voice traffic is marked with the appropriate DSCP value. The service provider requires that voice bearer traffic use EF ( Expedited Forwarding). Which DSCP value should be configured on the IP phones for voice media?

Hard
191

A company's main site runs a Cisco Unified Communications Manager (CUCM) cluster. They are adding a new remote branch that will have 50 IP phones. The branch has limited bandwidth and must survive a WAN outage with basic call functionality between local phones. Which design approach should be used at the branch?

Medium
192

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?

Hard
193

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

Hard
194

Which THREE of the following items can be defined within a Device Pool?

Hard
195

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?

Medium
196

Which service in CUCM is responsible for handling the registration of SIP devices?

Medium
197

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.)

Hard
198

In a Cisco collaboration design, you are tasked with identifying the DHCP Option required for Cisco IP Phones to discover the TFTP server address automatically. Which option is standard for this purpose?

Medium
199

When designing a redundant CUCM deployment, which mechanism ensures that if a primary subscriber fails, phones automatically register to a secondary subscriber?

Medium
200

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?

Medium
201

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?

Medium
202

Which THREE of the following items must be verified during a site-to-site VPN check for collaboration traffic?

Hard
203

You are designing a solution for secure voice signaling. Which protocol provides encryption for SIP signaling messages in a CUCM environment?

Medium
204

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

Easy
205

Which protocol is used by IP phones to register with the Cisco Unified Communications Manager?

Easy
206

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?

Medium
207

A Cisco Webex Room Kit is registered to CUCM on-premises. The administrator wants to enable encryption for signaling and media. Which protocol does the device use for secure signaling when registered to CUCM?

Medium
208

You are configuring Webex Hybrid Data Security (HDS). What is the purpose of the 'Key Management Service' (KMS) in this architecture?

Hard
209

A collaboration engineer is deploying Cisco Webex Hybrid Message Service with Cisco Unified Communications Manager (CUCM) and Expressway-C. The requirement is to enable secure instant messaging and presence between on-premises CUCM users and Webex. Which two components are required for this deployment? (Choose two.)

Medium
210

A user is unable to receive incoming PSTN calls via a Webex Calling Local Gateway. You observe that the INVITE from the provider reaches the CUBE, but the CUBE sends a 403 Forbidden. What is the most likely cause?

Hard
211

A company has deployed Webex Hybrid Call Service Connect to allow Webex App users to make calls using their on-premises Cisco Unified Communications Manager (CUCM) infrastructure. Users report that they can see presence but cannot make calls. Which component should be checked first to ensure that call signaling is working?

Medium
212

You are configuring DNS SRV records to support Jabber service discovery. Which domain format is correct for the _collab-edge._tls record?

Hard
213

A Cisco Unified Border Element is deployed between Cisco Unified Communications Manager and a SIP provider. The provider requires that the gateway insert a Diversion header containing the original called number when a call is forwarded. The engineer plans to use a SIP profile to accomplish this. Which statement accurately describes the capability of SIP profiles in this scenario?

Hard
214

Which log file is most useful for troubleshooting registration issues between an IP phone and CUCM?

Medium
215

Which option allows a customer to keep their existing PSTN numbers while moving to Webex Calling?

Medium
216

Which THREE actions are possible using SIP profiles on a CUBE?

Hard
217

You are designing Quality of Service (QoS) for a Cisco Collaboration deployment. The customer wants to ensure that voice traffic is prioritized over data traffic. Which marking should be applied to voice bearer traffic on Cisco IP Phones and switches?

Medium
218

When troubleshooting a Hybrid Media Service node, which log file is most critical for determining if the media is being routed correctly to the cloud?

Medium
219

Which THREE parameters are affected when you change the 'Location' of a device?

Hard
220

A network designer is implementing QoS for a Cisco Collaboration deployment. Which two statements about the trust boundary in a Cisco QoS design are true? (Choose two.)

Medium
221

A collaboration engineer is deploying a new Cisco Webex Room Kit in a conference room. The endpoint will send 1080p video at 3 Mbps. The network administrator needs to ensure that the video traffic is marked with the appropriate DSCP value and receives proper treatment in the QoS policy. Which DSCP value should be used for this interactive video traffic?

Medium
222

You are configuring a SIP trunk between CUCM and a CUBE. Which setting is critical to ensure that the SIP signaling is encrypted?

Medium
223

A company is implementing Webex Edge Connect. They require a dedicated circuit. Who must they coordinate with to set up the physical connection?

Hard
224

Where in Webex Control Hub do you go to view the health status of all deployed Hybrid Services connectors?

Easy
225

A network engineer is configuring a QoS policy on a Cisco IOS XE router for a collaboration deployment. The engineer needs to ensure that voice traffic is placed in a low-latency queue and that the queue has a strict priority, but also wants to limit voice traffic to 1 Mbps to prevent starvation of other traffic. Which queuing mechanism should be used?

Medium
226

You are migrating a legacy PBX to CUCM. You need to normalize incoming caller IDs from the PSTN to E.164 format. Which tool is best suited for this at the gateway level?

Hard
227

Which component in the Cisco Collaboration architecture provides the initial configuration files (XML) to an IP phone upon registration?

Easy
228

A Cisco Unified Border Element (CUBE) is deployed between Cisco Unified Communications Manager and a SIP provider. The provider sends an INVITE with a Diversion header containing the original called number. You need to strip the Diversion header before sending the INVITE to Unified CM. Which configuration element should you use?

Hard
229

You have configured a Cisco Unified CM Route List with two Route Groups: one containing a SIP trunk to Provider A and another containing a SIP trunk to Provider B. You want calls to be attempted to Provider A first, and only if that fails, to Provider B. Which Route List configuration ensures this behavior?

Medium
230

What is the primary benefit of the 'Webex Edge' strategy?

Easy
231

A collaboration administrator is troubleshooting a Webex Hybrid Services deployment. The connector for Hybrid Calendar Service shows as 'Down' in Control Hub. The administrator has verified that the connector server has network connectivity to the internet. Which additional check should be performed first to resolve the connector status?

Easy
232

A Cisco IOS XE voice gateway is configured with two POTS dial peers pointing to the same FXO port. Dial peer 10 matches destination pattern 911, and dial peer 20 matches destination pattern 9T. An inbound PSTN call arrives and is matched to a VoIP dial peer that forwards it to the gateway's FXO trunk. Which dial peer will the gateway use for the outbound POTS leg, and why?

Medium
233

You are monitoring RTP traffic using a protocol analyzer. You observe that the Payload Type field in the RTP header is set to 0. Which codec is currently in use?

Medium
234

Which TWO tasks must be performed when setting up Webex Hybrid Calendar service with Microsoft Exchange?

Medium
235

A collaboration administrator is configuring a new site in Cisco Unified Communications Manager. The site has a 2 Mbps WAN link, and the administrator wants to prevent more concurrent G.711 calls than the link can support by defining the maximum audio bandwidth allowed. Which configuration element in Cisco Unified Communications Manager should the administrator configure?

Easy
236

A Cisco IOS XE voice gateway routes inbound PSTN calls to Cisco Unified Communications Manager. The gateway is configured with dial-peer voice 100 pots, which has no incoming called-number command, and dial-peer voice 200 voip, which points to the CUCM subscriber. An engineer needs the gateway to terminate incoming POTS calls on the POTS dial peer and match outbound calls to the VoIP dial peer based on the called number. Which command must be added to dial-peer voice 100 pots to ensure inbound calls are matched correctly?

Medium
237

You are verifying the network readiness for a Cisco TelePresence endpoint. Which tool would you use to measure the packet loss, latency, and jitter on the path to the CUCM cluster?

Medium
238

You are designing a dial plan with a centralized PSTN egress. What must you configure to ensure that local extensions can be dialed directly across sites?

Hard
239

Which protocol is required for the Webex Hybrid Directory Connector to communicate with on-premises Active Directory?

Easy
240

You notice high latency on calls placed through a Local Gateway. Which metric should you inspect in the Webex Control Hub to confirm the issue is with the network path?

Hard
241

What is the purpose of the 'Webex Service' account in Active Directory when using Directory Connector?

Easy
242

Which THREE network conditions contribute to poor VoIP call quality in an RTP stream?

Medium
243

A CUBE is configured for H.450.3 call forwarding, but it is not working. What is the most likely cause?

Hard
244

Which TWO of the following are functions performed by the CUBE as a Session Border Controller?

Medium
245

A company has deployed Webex Hybrid Message Service to integrate its on-premises Cisco Unified Communications Manager IM and Presence Service with Webex. Users complain that their presence status is not updating in Webex when they change it in the on-premises Jabber client. The administrator confirms that the Expressway-C and Expressway-E are registered and that the Hybrid Message Service connector is running. Which component should the administrator verify next to ensure presence federation is working?

Medium
246

An administrator is designing a hub-and-spoke collaboration deployment. The hub has a 100 Mbps WAN link shared by many branches, and the engineer needs to ensure that a single branch cannot consume more than its fair share of bandwidth during peak periods. The engineer also wants voice calls to remain prioritized. Which QoS mechanism should be configured on the hub router to achieve both goals?

Medium
247

Which TWO of the following are considered best practices for implementing QoS in a Cisco collaboration network?

Medium
248

Which Cisco feature is used to ensure voice traffic is prioritized over web traffic on a Cisco access switch?

Easy
249

Which TWO of the following are required components of a Cisco Local Gateway deployment? (Choose two)

Easy
250

Which THREE of the following items are verified during the Webex Hybrid Service connector installation? (Choose three)

Hard
251

When configuring Hybrid Call Service for Cisco Unified Communications Manager, which specific requirement must be met for the Expressway-C and Expressway-E pair?

Hard
252

When configuring CUBE for media flow-around, which command ensures the media goes directly between endpoints?

Medium
253

You want to implement 'Presence' so users can see the status of other users. Which service must be running on the IM and Presence server?

Medium
254

An administrator is deploying Webex Hybrid Calendar Service with an on-premises Microsoft Exchange 2019 environment. Users report that their Webex meetings are not being automatically added to their Outlook calendars. The administrator has already verified that the Expressway-C and Expressway-E connectors are registered and healthy in Control Hub. Which additional component must be installed and configured to enable the calendar integration?

Hard
255

A collaboration engineer is troubleshooting poor video quality on a Cisco Collaboration deployment. The engineer suspects that video traffic is not receiving appropriate QoS treatment and wants to verify the classification and marking on a Cisco IOS router. Which two actions should the engineer take to confirm that video traffic is being handled correctly? (Choose two.)

Hard
256

In a Cisco CUCM cluster, which node is responsible for managing the database and performing configuration updates?

Easy
257

A network engineer is configuring LLQ on a Cisco IOS router to protect voice traffic. The voice class is assigned a priority of 512 kbps. During periods of congestion, which mechanism ensures that voice packets are not delayed by lower-priority traffic?

Medium
258

In a Webex hybrid environment, what is the primary role of the Expressway-C?

Medium
259

Which component in CUBE is responsible for ensuring that the call session is terminated correctly?

Easy

Frequently asked questions

What does the troubleshooting domain cover on the CLCOR exam?
troubleshooting questions test whether you can apply the concept in context, not just recognise a definition.
How many questions are in this domain?
This page lists all 259 troubleshooting questions in the CLCOR question bank. The actual exam draws from this domain proportionally to its weighting in the official exam blueprint.
What is the best way to practise this domain?
Start with a short focused session (10 questions) to identify gaps, then work through explanations. Repeat with a longer session once the weak areas feel solid.
Can I practise only troubleshooting questions?
Yes — the session launcher on this page filters questions to this domain only. Choose any session length for inline explanations and scoring.