Be able to read a gateway configuration and determine why a call fails, then fix it using dial peers, SIP profiles, or registration settings. The single most important thing is matching the correct inbound and outbound dial peer, because most rejection and routing faults trace back to that.
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Voice Gateways And Session Border Controllers — choose a session length
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Domain overview
This domain covers Cisco IOS XE voice gateways and CUBE: POTS/VoIP dial peers, PRI and SIP trunks, registration with an ITSP, SIP profiles for normalization, and troubleshooting call rejections. Questions are scenario-based, asking you to interpret configurations, identify the cause of call failures, and select commands or features that fix signaling and routing problems.
Exam objectives
POTS and VoIP dial-peer matching, destination patterns, and inbound/outbound call legs
SIP trunk registration to an ITSP, registrar configuration, credentials, and registration refresh timers
CUBE SIP profiles for header manipulation, normalization, and dial-peer-level application
Troubleshooting tools such as debug ccsip messages and show sip-ua status for call rejection causes
Assuming a busy cause code always means trunk exhaustion, when a dial-peer mismatch or incorrect destination pattern can reject the call first.
Forgetting that SIP profile changes must be attached to the correct dial peer or globally, so normalization never takes effect.
Confusing registration refresh configuration under sip-ua with dial-peer session timers, causing registration to expire unexpectedly.
Click any question to see the full explanation and answer options, or start a focused practice session above.
You are deploying CUBE. Which command enables the CUBE functionality on the Cisco IOS XE router?
2A 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?
3When configuring CUBE for media flow-around, which command ensures the media goes directly between endpoints?
4What is the primary function of a dial-peer destination-pattern?
5When troubleshooting CUBE SIP normalization, which tool allows you to view the normalized SIP messages in real-time?
6Which component in CUBE is responsible for ensuring that the call session is terminated correctly?
7You need to enforce a specific codec for calls traversing a CUBE. Where is the most appropriate place to apply this configuration?
8A CUBE is receiving calls but rejecting them due to '488 Not Acceptable Here'. What is the most likely reason?
9Which command is used to configure the IP address or hostname of the destination device on a dial-peer?
10When configuring CUBE, why would you use a 'voice class uri' command?
11A CUBE is configured for H.450.3 call forwarding, but it is not working. What is the most likely cause?
12What is the result of applying 'voice translation-profile' to an incoming dial-peer?
13Which TWO of the following are functions performed by the CUBE as a Session Border Controller?
14Which TWO of the following are valid components of a Cisco IOS voice gateway configuration?
15Which THREE actions are possible using SIP profiles on a CUBE?
16Which TWO of the following are true regarding the use of voice translation-rules?
17A 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?
18An 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?
19You 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?
20A 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?
21You 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?
22A 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?
23A 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?
24A 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?
25A 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?
26A 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?
27A 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?
28A 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?
Be able to read a gateway configuration and determine why a call fails, then fix it using dial peers, SIP profiles, or registration settings. The single most important thing is matching the correct inbound and outbound dial peer, because most rejection and routing faults trace back to that.
The Courseiva CLCOR question bank contains 28 questions in the Voice Gateways And Session Border Controllers domain. Click any question to see the full explanation and answer breakdown.
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