Exam 350-801 topic 1 question 117 discussion

Table 7-1: For Region Configuration Settings, Default Codec with Other Regions From the drop-down list box, choose a default codec to use for calls between this region and other regions. Due to bandwidth constraints at most remote-site deployments, the recommended default codec setting between a new region and existing regions is G.729. https://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/4_2_1/ccmcfg/b02regio.html

The default audio codec for all calls through Cisco CallManager is G.711. https://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/4_2_1/ccmcfg/b02regio.html

Based on the exhibit, there is no explicit codec selection between Dallas-REG and Austin-REG, and the setting for both Audio Codec Preference List and Maximum Audio Bit Rate is left to "Keep Current Setting Given that no specific codec has been pre-configured between these regions, it is reasonable to assume that the system default codec will be used. In most Cisco systems, G.711 is the default codec unless another codec is explicitly configured. Therefore, the correct answer is: B. G.711.

Region Configuration Note The default audio codec for all calls through Cisco CallManager is G. 711. If you do not plan to use any other audio codec, you do not need to use regions. https://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/4_2_1/ccmcfg/b02regio.html

This parameter specifies the default maximum audio bit rate for each call between a particular region and another region (interregion) when the Use System Default option is selected as the Max Audio Bit Rate in the Region Configuration window for the region's relationship with the other region. For example, assume there are two regions, one named Chicago and the other named Dallas. If Chicago has the Use System Default option set for the Max Audio Bit Rate for the relationship with Dallas, and the value in this parameter is set to 16 kbps (iLBC, G.728), then each call between devices in the Chicago region and devices in the Dallas region can use supported 16 kbps codecs like G.728, or lower bit rate codecs like the 8 kbps G.729, but not higher bit rate codecs like the 64 kbps G.722. This is a required field. Default: 8 kbps (G.729)

it will use the default since it was not defined. https://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/4_2_1/ccmcfg/b02regio.html the default audio codec for all calls through Cisco CallManager is G.711. If you do not plan to use any other audio codec, you do not need to use regions.

It would be A - G.729. As It doesn't have an explicit inter-region setting to Austin-REG, it uses the System Default. The System Default list is referenced under Service Parameters, and the default Audio Codec Preference List specified is "Factory Default low loss". While G.711, MP4A-LATM, and OPUS are all higher in that list than G.729, they can't be used as the Dallas-REG region setting also use the System Default for the Maximum Audio Bit Rate, which references the "Default Interregion Max Audio Bit Rate" in Service Parameters. The system system value for that parameter is 8kbps, so only G.729 can be used.

Answer should be OPUS. Max bitrate is not defined between Dallas and Austin. Therefore, System Default of Inter-region Bitrate will apply which is 8kbps by default. As OPUS is a variable bitrate codec that can range from 6-150kbps, it meets the maximum bitrate requirement. As it's higher in the codec preference list by default, it should be chosen.

A: G.729 => Default Interregion Max Audio Bit Rate = 8 kbps (G.729) Default Interregion Max Audio Bit Rate: This parameter specifies the default maximum audio bit rate for each call between a particular region and another region (interregion) when the Use System Default option is selected as the Max Audio Bit Rate in the Region Configuration window for the region's relationship with the other region. For example, assume there are two regions, one named Chicago and the other named Dallas. If Chicago has the Use System Default option set for the Max Audio Bit Rate for the relationship with Dallas, and the value in this parameter is set to 16 kbps (iLBC, G.728), then each call between devices in the Chicago region and devices in the Dallas region can use supported 16 kbps codecs like G.728, or lower bit rate codecs like the 8 kbps G.729, but not higher bit rate codecs like the 64 kbps G.722. This is a required field. Default: 8 kbps (G.729)

I believe B is the answer - G.711. The question is asking what codec should be used between Dallas and Austin. The Region configuration in this case only covers the relationship between Dallas and San Jose, which is set with a max bitrate of 24kbps. All other regions in this case are set to "Use System Default" and aren't configured under this region configuration. - I also believe we shouldn't assume connection to the other regions requires bandwidth preservation for audio calls, because it's not specified in the question. If the region configuration showed that the Austin region also required bandwidth preservation, then there wouldn't be an exact correct answer. If you'd choose opus, which can be set down to 6kbps, why wouldn't you just use choose G.729, which has a bitrate of 8kbps? - Because we want to keep quality as optimal as possible, while not exceeding the Maximum audio bitrate for the region in question, calls between Dallas and Austin will be using G.711 by default, and that's how it should stay.

D: Opus