CLCOR Infrastructure And Design Practice Test 2 — 15 Questions

Question 1

When deploying a high-availability CUCM cluster, how many subscribers are recommended to be associated with a single publisher for optimal database performance?

Accepted Answer

8. Cisco design guides recommend keeping the cluster size within specific limits to ensure database replication efficiency, typically a maximum of 8 subscribers per publisher.

Answer

16

Answer

4

Answer

32

Question 2

When designing for emergency services (E911) in a multisite deployment, what is the best practice for ensuring calls are routed to the correct Public Safety Answering Point (PSAP)?

Accepted Answer

Implement ELIN-based routing.. ELIN-based routing is the best practice for E911 in multisite deployments because it uses Emergency Location Identification Numbers (ELINs) to route emergency calls to the correct PSAP based on the caller's physical location. Each ELIN is associated with a specific PSAP and is configured in the CUCM database. When an emergency call is made, CUCM matches the caller's location to an ELIN and sends that ELIN to the PSAP, ensuring accurate dispatch.

Answer

Route all calls to a central office.

Answer

Use the caller's IP address.

Answer

Disable emergency routing.

Question 3

An administrator is configuring a new Cisco Unified Communications Manager (CUCM) cluster with a publisher and two subscribers. The publisher is running the Cisco CallManager service, and the subscribers are also running the Cisco CallManager service. The administrator wants to ensure that if a subscriber fails, the phones registered to it can re-register to another subscriber. Which configuration is required to achieve this?

Accepted Answer

Configure a Device Pool with the appropriate CUCM Group as the primary and a different CUCM Group as the secondary.. To ensure phones can re-register to another subscriber if their primary CUCM server fails, the Device Pool must reference a CUCM Group that includes the primary and secondary CUCM servers in the desired order. The CUCM Group defines the list of servers that devices use for registration and call processing. Other options do not provide this functionality.

Answer

Configure the phones to use the publisher as the primary TFTP server and a subscriber as the secondary.

Answer

Create a new Region and assign it to the Device Pool.

Answer

Enable Cisco Unified Communications Manager Assistant (CUMA) on the subscribers.

Question 4

You are designing a Cisco Collaboration solution for a company with 3,000 users across three buildings on a single campus. The customer wants to ensure that if the Cisco Unified Communications Manager (CUCM) publisher fails, the system continues to operate with minimal disruption and that administrative changes can still be made. Which deployment approach should you recommend?

Accepted Answer

Deploy a CUCM cluster with one publisher and multiple subscribers, and configure each phone with a list of up to three TFTP servers and a call processing server list.. The correct design uses a CUCM cluster with one publisher and multiple subscribers, and configures endpoints with redundant server lists. This provides call processing redundancy, allows administrative changes during a publisher outage if the publisher is restored, and is the Cisco-validated approach for high availability. The other options either introduce unsupported configurations or fail to protect on-campus users from a server failure.

Answer

Deploy a single CUCM server with Cisco Unified Survivable Remote Site Telephony (SRST) at each building to provide redundancy.

Answer

Deploy two CUCM publishers in the same cluster for database redundancy and load balancing.

Answer

Deploy a single CUCM subscriber and use the publisher only for database replication.

Question 5

A collaboration engineer is designing a centralized call-processing deployment where four branch offices connect to the data center over MPLS. Each branch has 40 G.711 phones, and the WAN links are 2 Mbps with 200 ms round-trip latency. The design must keep all call control in the data center while ensuring that branch phones can still place internal calls if the WAN fails. Which design element should be added to meet the requirement?

Accepted Answer

Enable Survivable Remote Site Telephony (SRST) on the branch voice gateway and configure the CUCM cluster to reference it as the SRST reference.. SRST on the branch gateway provides local call control for phones when the WAN to the centralized CUCM cluster fails. Configuring the gateway as an SRST reference in CUCM ensures phones automatically fall back to it. This preserves centralized call processing while meeting the requirement for internal calling during WAN outages, unlike TFTP redundancy or additional CUCM nodes.

Answer

Deploy a Cisco Unified Communications Manager Express (Unified CME) router at each branch for SRST fallback.

Answer

Configure each branch phone with a secondary TFTP server located at the branch office.

Answer

Deploy a CUCM subscriber node at each branch office and add it to the same cluster.

Question 6

You are designing a Cisco Unified Communications Manager (CUCM) cluster for a large enterprise with 10,000 users. The customer requires high availability and disaster recovery. The primary data center is in New York, and a secondary data center is in Chicago. Which strategy should be used for the CUCM database replication and call processing redundancy?

Accepted Answer

Deploy a single CUCM cluster with nodes in both data centers and configure network connectivity with low latency for database replication.. A single CUCM cluster with nodes in both data centers is the recommended design for high availability and disaster recovery, provided that the inter-site latency is low enough to support database replication. This allows endpoints to register to any node, and if one site fails, they can re-register to nodes in the other site. It simplifies management and ensures consistent dial plan and features across the enterprise.

Answer

Deploy two separate CUCM clusters (one in New York, one in Chicago) and use intercluster trunks for call routing.

Answer

Deploy a single CUCM cluster with all nodes in New York and use Cisco Unified Survivable Remote Site Telephony (SRST) at the Chicago site for redundancy.

Answer

Deploy a single CUCM cluster with the publisher in New York and all subscribers in Chicago, using database replication over the WAN.

Question 7

A collaboration engineer is configuring a Cisco Unified Border Element (CUBE) to connect a CUCM cluster to an ITSP. The ITSP requires that all outbound calls use SIP over TLS with SRTP encryption. The engineer has configured a SIP trunk on CUCM pointing to CUBE. Which additional configuration is required on CUBE to meet the ITSP's requirement?

Accepted Answer

Configure a crypto PKI trustpoint and enable SIP TLS with 'sip-ua' and 'transport tcp tls' commands.. Enabling SIP over TLS on CUBE requires a PKI trustpoint for certificates and the 'transport tcp tls' command under the dial peer or globally via 'sip-ua'. This encrypts signaling. SRTP for media encryption is configured separately with 'srtp' commands. The trustpoint and transport settings are essential to meet the ITSP's requirement for secure signaling.

Answer

Enable SRTP by configuring 'srtp fallback' under the voice service voip configuration.

Answer

Configure 'requri' under the SIP user agent to require TLS for all outbound calls.

Answer

Configure 'voice-class sip security pass-thru' under the dial peer to allow encrypted signaling.

Question 8

A network engineer is configuring a Cisco Unified Communications Manager (CUCM) cluster to support a new SIP trunk to an ITSP. The ITSP requires that all outbound calls present a specific number as the calling party number. Which CUCM configuration element should be used to manipulate the calling party number for calls routed over this SIP trunk?

Accepted Answer

Translation Pattern. Translation Patterns are the correct tool for manipulating calling party numbers in CUCM. They allow you to match specific patterns and transform the calling party number before the call is sent to the SIP trunk. This ensures compliance with the ITSP's requirements. Other elements like Route Groups, Route Lists, and SIP Profiles do not perform this function.

Answer

Route Group

Answer

SIP Profile

Answer

Route List

Question 9

A collaboration architect is designing a Cisco Unity Connection voicemail deployment integrated with CUCM using SIP. The design must support 5000 users with high availability and must allow voicemail port failover if a Unity Connection node fails. Which design approach should be used?

Accepted Answer

Deploy two Unity Connection nodes in a cluster with the publisher and subscriber, and configure CUCM with a SIP trunk to each node for redundancy.. Cisco Unity Connection high availability is achieved by clustering two nodes (publisher and subscriber). CUCM is configured with SIP trunks to both nodes, allowing it to route voicemail calls to the active node. If one node fails, calls are routed to the surviving node, providing port failover. This design supports 5000 users and meets the availability requirement.

Answer

Deploy Unity Connection in a multi-site model with each site having its own standalone Unity Connection server, and use a global dial plan for voicemail access.

Answer

Deploy a single Unity Connection node with a Cisco Unified SIP Proxy (CUSP) in front to distribute calls.

Answer

Use a single Unity Connection node and rely on CUCM's SRST for voicemail failover.

Question 10

A collaboration engineer is designing a Cisco Unified Communications Manager (CUCM) cluster for a new deployment. The customer requires that the system support secure signaling and media encryption for all calls. Which two components must be configured to enable secure signaling and media encryption for SIP calls between CUCM and Cisco IP Phones? (Choose two.)

Accepted Answer

Install a Certificate Authority Proxy Function (CAPF) certificate on the phones.. To secure signaling and media between CUCM and Cisco IP Phones, you must enable encryption in the phone's device security profile and install a CAPF certificate on the phones. The device security profile setting ensures the phone uses TLS for signaling and SRTP for media. The CAPF certificate provides the phone with a locally significant certificate, which is required for secure authentication. Together, these components establish a secure connection.

Answer

Configure a secure SIP trunk to the phones.

Answer

Enable 'SRTP' in the enterprise parameters.

Answer

Configure a Secure SIP Profile on the SIP trunk.

Question 11

A collaboration engineer is troubleshooting a call routing issue in a Cisco Unified Communications Manager (CUCM) cluster. Users report that when they dial a specific long-distance number, they hear a fast busy tone. The engineer checks the dialed number analysis and sees that the call matches a route pattern that points to a SIP trunk to the PSTN. The SIP trunk is registered and operational. Which CUCM feature should the engineer check to determine why the call is failing?

Accepted Answer

Route Pattern's 'Calling Party Transformation' settings. When a call matches a route pattern and is sent to a SIP trunk but fails with a fast busy tone, the issue may be due to calling party number manipulation. The PSTN provider may reject the call if the calling party number is not in a valid format or is not authorized. Checking the calling party transformation settings on the route pattern can reveal if the number is being altered incorrectly. Other settings like CSS or trunk destination would typically cause different failures.

Answer

Calling Search Space (CSS) of the phone

Answer

SIP trunk's Destination Address

Answer

Route Pattern's 'Route This Pattern' setting

Question 12

You are deploying a Cisco Unified Border Element (CUBE) to connect a Cisco Unified Communications Manager (CUCM) cluster to a SIP trunk service provider. The provider requires that all outbound calls use a specific SIP header for billing and that early media (ringback) is passed correctly. During testing, you notice that calls fail when the provider sends a 183 Session Progress with SDP, and the caller does not hear ringback. Which CUBE configuration is most likely missing to allow early media and proper SIP header manipulation?

Accepted Answer

voice service voip with sip and the command 'sip-profiles' to manipulate headers, and 'media flow-through' to allow early media. Early media requires the CUBE to pass provisional SIP responses with SDP and to allow the media stream to flow before the call is answered. Using SIP profiles to manipulate headers (for billing) and configuring media flow-through ensures that both requirements are met. The other options either misapply commands or do not address the early media requirement.

Answer

voice class sip-profiles with rule to modify the From header and enable early-offer

Answer

voice service voip with sip and the command 'early-offer forced'

Answer

voice class sip-profiles with rule to modify the P-Asserted-Identity header and allow-connections sip to sip

Question 13

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?

Accepted Answer

class-map match-any VOICE; match dscp ef; policy-map VOICE-POLICY; class VOICE; priority 1000. The correct configuration is to match DSCP EF (46) in a class-map and apply the 'priority' command with a bandwidth value in the policy-map. This maps voice traffic to a low-latency priority queue, ensuring proper prioritization. The 'priority 1000' command creates a strict priority queue with a policed bandwidth of 1000 kbps, which is ideal for voice.

Answer

class-map match-any VOICE; match protocol sip; policy-map VOICE-POLICY; class VOICE; queue-limit 100

Answer

class-map match-all VOICE; match dscp cs4; policy-map VOICE-POLICY; class VOICE; bandwidth 1000

Answer

class-map match-any VOICE; match dscp ef; policy-map VOICE-POLICY; class VOICE; fair-queue

Question 14

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?

Accepted Answer

Option 150. DHCP Option 150 is the Cisco-proprietary option that delivers a list of TFTP server IP addresses to Cisco IP Phones during DHCP scope configuration. Phones use this to locate the TFTP server, download their configuration XML and firmware, and register with CUCM. Option 66 is the standard (RFC 2132) TFTP server name option and can also work, but Option 150 is the Cisco-standard answer for IP phone TFTP discovery.

Answer

Option 66

Answer

Option 128

Answer

Option 43

Question 15

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

Accepted Answer

Point all CUCM nodes to the same external NTP stratum 1 or 2 servers.. Cisco Collaboration best practice requires every CUCM node (publisher and subscribers) to synchronize directly with the same external, reliable NTP source — typically stratum 1 or 2 servers. This ensures consistent, accurate time across all nodes, which is critical for database replication, CDR timestamps, certificate validation, and log correlation. Pointing all nodes to the same external source avoids a single point of failure and prevents time drift that could break cluster operations.

Answer

Configure NTP only on the publisher node.

Answer

Point each CUCM node to a different NTP server for redundancy.

Answer

Use the publisher as the NTP server for all subscriber nodes.