CLCOR Voice Gateways And Session Border Controllers Practice Test 3 — 15 Questions

Question 1

An engineer is configuring a Cisco IOS XE voice gateway to support a T1 PRI connection to the PSTN. The gateway must use the ISDN switch type for North America. Which command correctly configures the T1 controller for ISDN PRI?

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

Accepted Answer

isdn switch-type primary-ni. For a T1 PRI connection in North America, the correct ISDN switch type is primary-ni (National ISDN). This command configures the gateway to use the standard signaling protocol for North American PRI circuits. Other switch types like primary-net5 are for Europe, and basic-ni is for BRI, not PRI.

Answer

isdn switch-type primary-net5

Answer

isdn switch-type basic-ni

Answer

isdn switch-type primary-dms100

Question 2

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

Accepted Answer

mode border-element. CUBE (Cisco Unified Border Element) is enabled on IOS XE by entering voice service configuration mode and issuing the 'mode border-element' command. This switches the router's voice service into border-element mode, activating the SIP-based session border controller functionality that provides demarcation, protocol interworking, and security between the enterprise and the service provider.

Answer

enable cube

Answer

voice-service enable

Answer

service cube

Question 3

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?

Accepted Answer

debug voip dialpeer all. The command 'debug voip dialpeer all' enables debugging for all dial-peer matching events, showing which dial-peer is matched for incoming calls. This helps identify why a dial-peer is not matching, as it displays the matching process and the resulting dial-peer number.

Answer

show voice call status

Answer

show dial-peer voice summary

Answer

debug ccsip messages

Question 4

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

Accepted Answer

media flow-around. The 'media flow-around' command in CUBE configuration tells the Cisco Unified Border Element to leave the RTP media streams out of the signaling path, allowing endpoints to exchange media directly. This is the correct syntax for enabling media flow-around on CUBE. It is configured under the voice service voip or dial-peer context to control whether media is anchored or bypassed.

Answer

media pass-through

Answer

media-bypass

Answer

media flow-through

Question 5

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

Accepted Answer

To match the dialed number. The primary function of a dial-peer destination-pattern is to match the dialed number (or digits) to determine which dial-peer to use for routing the call. It acts as a matching criterion for inbound and outbound dial-peers. The other options describe different dial-peer attributes.

Answer

To define the codec

Answer

To specify the gateway IP

Answer

To enable SIP

Question 6

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

Question 7

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

Accepted Answer

SIP Stack. The SIP Stack in CUBE is the protocol engine that handles SIP signaling end-to-end, including session setup, in-dialog requests, and proper session teardown via BYE transactions. It ensures that call sessions are terminated correctly by managing the SIP dialog state machine and sending/receiving the appropriate messages.

Answer

Dial-peer

Answer

Voice translation-profile

Answer

Voice-class codec

Question 8

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

Accepted Answer

Voice class codec applied to dial-peer. Codec enforcement on CUBE is applied via a voice class codec that is referenced by the dial-peer handling the call. The dial-peer is where media capabilities are negotiated for that call leg, so binding the codec class there gives per-destination control. Global voice service, SIP profiles, and interface configs do not enforce codecs.

Answer

Global voice service

Answer

SIP profile

Answer

Under the interface

Question 9

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

Accepted Answer

Codec mismatch. SIP 488 'Not Acceptable Here' is returned when the called party cannot support the media parameters in the offer — most commonly a codec mismatch where the offered codec (e.g., G.729) is not configured on any matching dial-peer on the CUBE. CUBE rejects the INVITE because it cannot negotiate a compatible codec between the inbound and outbound legs.

Answer

Authentication failure

Answer

SIP registration expired

Answer

Dial-peer inactive

Question 10

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

Accepted Answer

session target. The 'session target' command is used on a dial-peer to specify the destination IP address or hostname of the next-hop device for that dial-peer. It is a fundamental command in Cisco IOS voice gateway configuration for directing calls. The other options are not valid Cisco IOS commands for this purpose.

Answer

target ip

Answer

call target

Answer

destination-ip

Question 11

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

Accepted Answer

To match SIP URI host. The 'voice class uri' command in CUBE is used to define a class of SIP URIs for matching purposes, typically to match the host portion of a SIP URI. This allows CUBE to categorize incoming or outgoing SIP requests based on the URI host, which can then be referenced in dial peers for routing or policy decisions. It is a key tool for URI-based routing and manipulation.

Answer

To define codec

Answer

To route by time

Answer

To match caller ID

Question 12

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

Accepted Answer

Incompatible signaling protocol. H.450.3 is a supplementary service for call diversion (call forwarding) defined within the H.323 protocol suite. For H.450.3 to function, the signaling protocol on the dial-peer must be H.323 — it cannot work over SIP or other signaling protocols because H.450.x supplementary services are H.323-specific constructs. If the CUBE is configured with SIP signaling on the relevant dial-peers, H.450.3 call forwarding will never trigger, making incompatible signaling protocol the most likely cause.

Answer

Dial-peer not defined

Answer

Codec mismatch

Answer

SIP profile missing

Question 13

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

Accepted Answer

It modifies the digits. A voice translation-profile applied to an incoming dial-peer rewrites the calling, called, or redirecting numbers before the call is matched and routed. It uses translation rules to manipulate digits (add, strip, replace prefixes), which is why the correct result is digit modification.

Answer

It enables SIP

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It changes the codec

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It drops the call

Question 14

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

Accepted Answer

Media interworking. Option B (Media interworking) is correct because a CUBE acting as a Session Border Controller terminates the signaling and media on both legs, allowing it to transcode between different codecs (e.g., G.711 to G.729) and perform media flow-around or flow-through, which is a core SBC function. Option E (Topology hiding) is correct because CUBE uses back-to-back user agent (B2BUA) behavior to strip and rewrite SIP headers such as Via, Record-Route, and Contact, concealing the internal CUCM/ITSP topology from the far-end network. Option A (Call routing in CUCM) is not an SBC function; dial plan and call routing decisions are performed by Cisco Unified Communications Manager, not CUBE. Option C (IP phone registration) is handled by CUCM's TFTP and SCCP/SIP registration services, not by CUBE. Option D (Voice mail storage) is provided by Cisco Unity Connection, not by CUBE.

Answer

Call routing in CUCM

Answer

IP phone registration

Answer

Voice mail storage

Question 15

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

Accepted Answer

Dial-peers. Dial-peers (B) are a core component of Cisco IOS voice gateway configuration, defined globally with the dial-peer voice command to match inbound/outbound call legs and specify destination patterns, sessions targets, and codecs. Voice translation rules (D) are also valid IOS voice gateway components, configured with the voice translation-rule and voice translation-profile commands to manipulate calling/called numbers via regex. In contrast, a phone button template (A) is a Cisco Unified Communications Manager (CUCM) configuration element applied to IP phones, not an IOS gateway feature. A CUCM route pattern (C) is configured on CUCM to route calls toward gateways or trunks, not on the IOS gateway itself. A device pool (E) is likewise a CUCM construct that groups devices for common settings such as region, date/time, and softkey templates, and is not part of IOS gateway configuration.

Answer

Phone button template

Answer

CUCM route pattern

Answer

Device pool