Cisco 500-444 Online Access

External voice DNs are sourced from CUCM in a CCE Dial Plan. External voice DNs are the DNs that are not associated with any CCE device, such as agent phones, VRU peripherals, or gateways. They are used to route calls to destinations outside the CCE network, such as PSTN numbers, voicemail, or other PBXs. CUCM is responsible for provisioning and managing these DNs and assigning them to the appropriate devices or trunks. CVP can also use external voice DNs to send calls to CUCM for further routing or treatment.

References:

• Troubleshooting Cisco Contact Center Enterprise (CCET) course, Module 3: Troubleshooting Call Flow Issues, Lesson 3.1: Troubleshooting CCE Call Flows, Topic: CCE Dial Plan1
• Configuration Guide for Cisco Unified Customer Voice Portal, Release 12.6 (1) - System Configuration [Cisco Unified Customer Voice Portal] - Cisco, Chapter: Dialed Number Pattern Configuration2

A voice gateway (VGW) is a device that connects a traditional telephony network, such as a TDM trunk, to a voice over IP (VoIP) network, such as a Cisco Unified Communications Manager (CUCM) cluster. A VGW performs signaling and media conversion between the two networks, and can also provide supplementary services, such as call routing, digit manipulation, transcoding, conferencing, and fax relay. A VGW can be a standalone device, such as a Cisco Integrated Services Router (ISR), or a software module, such as a Cisco Unified Border Element (CUBE). A CUBE is a special type of VGW that can also provide security, demarcation, and interworking functions for VoIP calls. A CUBE can be deployed between two VoIP networks, such as CUCM and a service provider SIP trunk, or between a TDM trunk and a VoIP network, in which case it acts as both a CUBE and a VGW. A CUCM is not a VGW, but a call control platform that manages VoIP endpoints, such as IP phones, and interacts with VGWs for call routing and signaling. A CUSP is a Cisco Unified SIP Proxy, which is a device that provides SIP routing and load balancing for VoIP networks. A CUSP is not a VGW, but a SIP proxy server that can work with CUCM and CUBE to optimize SIP call flows. References:

• Troubleshooting Cisco Contact Center Enterprise (CCET), Module 1: Voice Gateway Overview1
• Cisco Contact Center Enterprise Implementation and Troubleshooting (CCEIT), Module 2: Voice Gateway Configuration2
• Cisco Unified Border Element Configuration Guide3
• Cisco Unified SIP Proxy Configuration Guide4

 The keytool command that lists certificates in the cacerts file is B: keytool -list -keystore cacerts. This command will display the aliases and fingerprints of all the certificates in the cacerts file, which is the default truststore for Java applications1. The cacerts file contains the root and intermediate certificates of various certificate authorities (CAs) that are trusted by Java2.

The other options are incorrect because:

• A: keytool -list -showinfo is not a valid keytool command, as the -showinfo option does not exist. The closest option is -v or -verbose, which will display more details about each certificate, such as the owner, issuer, serial number, validity period, signature algorithm, and extensions1.
• C: keytool -list cacerts is not a complete keytool command, as it is missing the -keystore option, which is required to specify the name or path of the keystore file to be listed. Without the -keystore option, the keytool command will assume the default keystore file, which is usually named .keystore in the user’s home directory1.
• D: keytool -list -alias is also not a complete keytool command, as it is missing the value of the -alias option, which is used to specify the alias of a particular entry in the keystore file to be listed. Without the value of the -alias option, the keytool command will display an error message, such as "keytool error: java.lang.Exception: Alias <alias> does not exist"1.

References:

1: keytool - Key and Certificate Management Tool 2: How to check a Certificate is in default cacerts 3: java - How to view and edit cacerts file? - Stack Overflow 4: HOW TO: Import or list certificates from Java cacerts file using … 5: Keytool: List Certificate - Java Certs - ShellHacks

n Contact Center Enterprise with Cisco Unified Customer Voice Portal (CVP) and Cisco Unified Border Element (CUBE) deployment, CUBE must be configured as media pass flow-through mode. This means that CUBE will terminate and reoriginate both the signaling and media streams for each call leg. This allows CUBE to perform media manipulation, such as transcoding, transrating, DTMF interworking, and media forking. Media pass flow-through mode is required for CUBE to support advanced features for contact center, such as courtesy call back, contact center survivability, and encrypted (SRTP) trunks. Media pass flow-around mode, where CUBE only terminates and reoriginate the signaling stream and lets the media stream bypass CUBE, is not supported for contact center solutions. A voice gateway must not be dedicated for VXML browser sessions, as CUBE can coexist with VXML gateway on the same platform. Box-to-box CUBE can be used for redundancy, but it is not a mandatory configuration for contact center solutions123. References:

• Cisco Unified Border Element Configuration Guide - Cisco IOS XE 17.6 Onwards - Advanced Features for Cisco Contact Center2
• Cisco Unified Border Element (Enterprise) Fundamentals and Basic Setup4
• Cisco Unified Border Element for Contact Center Solutions5