Effects of DSP Oversubscription on Analog Phone off-hook
Question
When DSP oversubscription occurs on a Cisco IOS router using DSP modules that are based on the C5510 chipset, what will happen when an analog phone connected to a FXS port goes off-hook?
Answers
Explanations
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A. B. C. D. E.E.
When DSP oversubscription occurs for both analog ports and digital ports, except PRI and BRI.
FXO signaling and application controlled endpoints are not supported.
This feature does not apply to insufficient DSP credits due to mid-call codec changes (while a call is already established).
When DSP (Digital Signal Processor) oversubscription occurs on a Cisco IOS router, it means that there are not enough DSP resources available to handle all of the voice traffic being sent through the system. This can happen when there are more calls or channels being used than the available DSP resources can support.
In the case of Cisco IOS routers using DSP modules based on the C5510 chipset, if DSP oversubscription occurs and an analog phone connected to an FXS (Foreign Exchange Station) port goes off-hook, the phone will not receive a dial tone.
Instead, one of the following three things will happen, depending on how the router has been configured:
A fast busy tone will be played: This indicates that all available channels are currently in use and there is no capacity to handle additional calls.
A slow busy tone will be played: This indicates that there is some capacity available, but it is currently being reserved for higher-priority traffic.
A network busy tone will be played: This indicates that the network itself is congested and cannot handle any additional traffic.
Option D, which suggests that a dial tone will be played but digits will not be processed, is not correct. When DSP oversubscription occurs, the phone will not receive a dial tone at all.
Option E, which suggests that no tone will be played, is not entirely accurate either. While it is true that the phone will not receive a dial tone, it will receive one of the three busy tones mentioned above, indicating that there is currently no capacity available to handle the call.
In summary, when DSP oversubscription occurs on a Cisco IOS router using DSP modules based on the C5510 chipset and an analog phone connected to an FXS port goes off-hook, the phone will not receive a dial tone. Instead, it will receive one of three possible busy tones, depending on the configuration of the router and the availability of DSP resources.
