22 questions · Voice Gateways And Session Border Controllers · All types, answers revealed
You need to enforce a specific codec for calls traversing a CUBE. Where is the most appropriate place to apply this configuration?
This is the standard method for codec selection on a dial-peer.
Why this answer
A voice class codec is defined globally and then applied to the specific dial-peer using the voice-class codec command.
When troubleshooting CUBE SIP normalization, which tool allows you to view the normalized SIP messages in real-time?
This displays the SIP messages being processed by CUBE.
Why this answer
debug ccsip messages provides the view of the SIP signaling, including headers modified by normalization.
Which TWO of the following are valid components of a Cisco IOS voice gateway configuration?
The basis for call routing.
Why this answer
Dial-peers and voice translation rules are core components of voice gateway configuration.
Which THREE factors influence dial-peer matching for incoming calls on a Cisco IOS XE gateway?
Matches the calling number (ANI).
Why this answer
Incoming dial-peer selection is based on the DNIS (called number), ANI (calling number), and the incoming port/SIP URI.
You are deploying CUBE. Which command enables the CUBE functionality on the Cisco IOS XE router?
This is the required command to activate CUBE.
Why this answer
The mode border-element command is required under the voice service voip configuration to enable CUBE features.
When configuring CUBE, why would you use a 'voice class uri' command?
This allows matching based on the SIP URI.
Why this answer
Voice class URI is used to match incoming SIP requests based on the URI, such as the host portion of the SIP message.
What is the primary function of a dial-peer destination-pattern?
destination-pattern matches the called number.
Why this answer
The destination-pattern defines the number or pattern that triggers the selection of a specific dial-peer.
Which TWO of the following are required to successfully register a CUBE with a SIP provider?
Credentials are required for registration authentication.
Why this answer
CUBE registration requires a SIP-UA configuration defining the authentication credentials and the registrar server.
You are configuring CUBE for SIP-to-SIP header manipulation. You need to remove the Diversion header from outgoing INVITE requests. Which component is required to achieve this?
SIP profiles allow for precise header removal or modification.
Why this answer
A SIP profile is required to match and modify or remove specific SIP headers in CUBE.
Which TWO of the following are true regarding the use of voice translation-rules?
Regex is the engine for pattern matching.
Why this answer
Translation rules use regular expressions to match and replace digits.
Which command is used to configure the IP address or hostname of the destination device on a dial-peer?
This defines where to send the call.
Why this answer
session target ipv4:x.x.x.x is the standard way to define the destination IP.
What is the result of applying 'voice translation-profile' to an incoming dial-peer?
Translation profiles modify digit patterns.
Why this answer
Translation profiles modify incoming or outgoing digits (calling or called numbers) to fit the dial plan.
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?
This command traces the dial-peer selection process.
Why this answer
debug voip dialpeer all shows the matching logic for both inbound and outbound dial-peers.
A CUBE is receiving calls but rejecting them due to '488 Not Acceptable Here'. What is the most likely reason?
488 indicates an SDP/media negotiation failure.
Why this answer
488 usually indicates a mismatch in media capabilities (codecs or SDP) offered vs what is configured on the dial-peer.
Which THREE commands are used to configure a SIP profile in CUBE?
Required to bind the profile to a dial-peer.
Why this answer
SIP profiles require creating a voice class, defining the match/modify rules, and applying it to a dial-peer.
Which THREE actions are possible using SIP profiles on a CUBE?
Used for header normalization.
Why this answer
SIP profiles can modify headers, remove headers, and add headers to SIP messages.
Which TWO of the following are valid methods to troubleshoot SIP call failures on a CUBE?
Provides snapshot of active call states.
Why this answer
debug ccsip messages and show call active voice are the primary tools for diagnosing SIP signaling and active session state.
A CUBE is configured for H.450.3 call forwarding, but it is not working. What is the most likely cause?
H.450 is H.323-based and doesn't translate natively to SIP supplementary services without gateway interworking.
Why this answer
H.450.3 is an H.323 supplementary service, which requires specific H.323 configuration and is often incompatible with SIP-based CUBE deployments without proper interworking.
What is the default dial-peer used if no other dial-peer matches a call on a Cisco IOS XE gateway?
Dial-peer 0 is the default catch-all.
Why this answer
Dial-peer 0 is the system default dial-peer that acts as a catch-all if no specific match is found.
Which TWO of the following are functions performed by the CUBE as a Session Border Controller?
Handles codec and signaling conversions.
Why this answer
CUBE performs topology hiding and media interworking between different SIP networks.
When configuring CUBE for media flow-around, which command ensures the media goes directly between endpoints?
This allows direct end-to-end media.
Why this answer
media flow-around prevents the CUBE from inserting itself into the media path.
Which component in CUBE is responsible for ensuring that the call session is terminated correctly?
The SIP stack handles call signaling and termination.
Why this answer
The SIP gateway functionality in IOS XE handles the SIP signaling state machine for call termination.
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