Resolving PRI DSP Resource Errors on Cisco ISR 4300
An engineer is configuring a PRI card on a Cisco ISR 4300 Series Router. When the engineer configures the voice PRI on the router, this error is received: "T1 0/1/0: No DSP resources to configure voice feature". Which action must the engineer take to resolve the issue if a PVDM card was installed in the motherboard?
Community Votes
83% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.
Community Insight
The exam tests knowledge of physical slot constraints and DSP assignment rules; the common trap is assuming motherboard resources are globally available to all interface modules.
This question addresses the hardware architecture of Cisco ISR 4000 Series routers regarding DSP resource allocation. The community consensus is that onboard PVDMs are reserved for IP services and cannot be shared with TDM NIM cards, requiring a dedicated NIM-PVDM.
Candidates often choose Option A (moving the card), mistakenly believing the issue is a slot conflict or compatibility error rather than a specific DSP resource availability constraint defined by the platform's hardware design.
Community Discussion (4 comments)
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Expert Analysis
Why the Answer Is Correct
On the Cisco ISR 4000 series, the motherboard PVDM slots are specifically designated for IP media processing tasks such as transcoding and conferencing. They are architecturally isolated from the Network Interface Module (NIM) slots used for traditional TDM interfaces like PRI. Therefore, when a T1/E1 NIM requires DSP resources for voice feature configuration, it must utilize a dedicated PVDM module installed directly into the NIM itself (NIM-PVDM).Why the Other Options Are Wrong
Option A is incorrect because moving the NIM to a different slot does not change the fact that the NIM cannot access motherboard PVDMs regardless of the slot position. Option B is irrelevant as there is no 'memory slot' replacement procedure for this type of resource error. Option C is incorrect because replacing flash does not allocate additional DSP hardware resources needed for the voice feature.Community Comment Notes
Comment [1] provides critical technical context, stating that while PVDM4 chips can be on the motherboard for IP services, they are not accessible to NIMs. Comment [2] reinforces this by noting that on-board PVDMs are for conferencing/transcoding only. Comment [3] offers a useful link to Cisco documentation explaining the NIM-PVDM concept, which validates the need for installing the DSP module on the NIM card.Official Reference
Exam Strategy
Always distinguish between IP-based DSP usage (motherboard) and TDM-based DSP usage (NIM/PIM) in ISR 4000 questions. If an error involves a legacy interface (PRI/BRI) lacking resources, look for solutions involving adding DSPs to the interface module itself.