CLCOR Infrastructure And Design Practice Test 2 — 15 Questions

Question 1

You are deploying a Cisco Expressway-E in a DMZ. Which port must be opened on the external firewall to allow for H.460.18/19 firewall traversal for H.323 endpoints?

Accepted Answer

1720. Port 1720 is the standard H.323 signaling port used for traversal through the Expressway-E.

Answer

5061

Answer

8080

Answer

443

Question 2

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

Accepted Answer

G.729. G.729 is the standard low-bandwidth codec that provides acceptable voice quality at 8kbps.

Answer

G.711

Answer

AAC-LD

Answer

G.722

Question 3

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.. The Device Pool and the associated Cisco Unified Communications Manager Group define which servers a device registers with and in what order.

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 4

You have a CUCM cluster with high utilization. Which parameter, when adjusted, helps mitigate the load on the TFTP service during a large-scale phone deployment?

Accepted Answer

TFTP File Load Factor. Setting the 'Enable Caching of Signed Files' and 'TFTP File Load Factor' helps optimize the TFTP server's ability to serve requests without overloading.

Answer

Keepalive Interval

Answer

Max Phone Registrations

Answer

Registration Timeout

Question 5

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

Accepted Answer

Cisco Unified Communications Manager. CUCM (Cisco Unified Communications Manager) is the primary call control agent responsible for call processing, routing, and device management.

Answer

Cisco Expressway

Answer

Cisco Unity Connection

Answer

Cisco CUBE

Question 6

When designing a Cisco Jabber deployment using MRA, which internal service is responsible for providing the configuration file and server list to the client?

Accepted Answer

Cisco Expressway-C. The Cisco Expressway-C (internal) acts as a proxy for the CUCM nodes to provide configuration files via HTTPS.

Answer

Cisco Unity Connection

Answer

IM and Presence Service

Answer

TFTP Server

Question 7

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, real-time video conferencing, one-way latency must be kept below 150ms to ensure a good user experience.

Answer

300ms

Answer

500ms

Answer

50ms

Question 8

You are implementing Quality of Service (QoS) for a Cisco IP Phone. Which mechanism ensures that the phone's traffic is tagged correctly even if the user connects a PC to the phone's auxiliary port?

Accepted Answer

Configure switchport voice vlan on the switch interface.. The 'switchport voice vlan' command on the access switch port allows the phone to use a dedicated voice VLAN while the PC uses the data VLAN.

Answer

Use an ACL to match PC MAC addresses.

Answer

Enable Auto-QoS on the switch port.

Answer

Assign a static IP to the PC.

Question 9

You are troubleshooting a registration failure for a remote IP phone. The phone is configured to use an Expressway-E for MRA. Which DNS record is queried by the client to find the Expressway-E cluster?

Accepted Answer

_collab-edge._tls. The _collab-edge._tls DNS SRV record is the first step in the MRA discovery process to locate the Expressway-E.

Answer

_cisco-uds._tcp

Answer

_sip._tls

Answer

_tftp._udp

Question 10

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

Accepted Answer

Publisher. The Publisher node is the primary node that holds the master database copy and handles all configuration changes.

Answer

Subscriber

Answer

TFTP node

Answer

Music on Hold (MoH) node

Question 11

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

Accepted Answer

Use a trusted third-party CA for all servers.. Using a trusted, third-party Certificate Authority (CA) ensures that all certificates are valid across both internal and external endpoints without security warnings.

Answer

Use self-signed certificates on all nodes.

Answer

Disable certificate verification on all endpoints.

Answer

Use the Publisher as the CA for the entire network.

Question 12

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

Accepted Answer

Use a dedicated Voice VLAN.. Phones should be placed in a dedicated Voice VLAN for security and QoS performance reasons.

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 13

You are designing a Call Admission Control (CAC) policy for a site with limited bandwidth. Which feature should you use to prevent over-subscription of the WAN link?

Accepted Answer

Location-based CAC. Location-based CAC in CUCM allows for setting bandwidth limits per site/region, preventing over-subscription.

Answer

Quality of Service (QoS)

Answer

Resource Reservation Protocol (RSVP)

Answer

Gatekeeper-based CAC

Question 14

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

Accepted Answer

Cisco CallManager Traces. The Cisco CallManager traces are essential for reviewing the registration/signaling exchange between the device and the call agent.

Answer

System Health Reports

Answer

Cisco TFTP Logs

Answer

Cisco Tomcat Logs

Question 15

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. An external load balancer is required to distribute incoming traffic across the cluster of Expressway-E nodes.

Answer

Cisco CUBE redundancy

Answer

Cisco UCM Group

Answer

DNS Round Robin only