Cisco SPA-DSP
Digital Signal Processor SPA
Product Highlights
As voice networks grow in complexity — spanning multiple codec standards, packetization rates, and signaling protocols — the need for dedicated, hardware-based media processing becomes critical. The Cisco SPA-DSP is a purpose-built Digital Signal Processor Shared Port Adapter designed for the Cisco ASR 1000 Series Aggregation Services Routers.
The SPA-DSP offloads CPU-intensive voice transcoding, transrating, and DTMF interworking tasks to dedicated DSP hardware, freeing the router's main processor for routing and forwarding duties. It works in conjunction with the Session Border Controller (SBC) application and Cisco Unified Border Element (CUBE) Enterprise to deliver carrier-grade media processing for SIP trunking, VoIP peering, and enterprise voice aggregation deployments.
With 21 DSP cores across seven SP2603 chips, the SPA-DSP supports up to 903 channels at low codec complexity — making it ideal for service providers and large enterprises that require high-density voice processing. The half-height, single-width SPA form factor installs into SIP10 or SIP40 interface processors and supports online insertion and removal (OIR) for non-disruptive maintenance. Note: This product has reached End-of-Sale status (May 1, 2020) and is available through secondary market channels.
Features & Benefits
High-Density Voice Transcoding
The SPA-DSP translates media streams between different codec types — enabling interoperability across networks using G.711, G.729, AMR-WB, iLBC, and other standards. This eliminates codec mismatch issues at peering points and enterprise SIP trunk boundaries, ensuring clear, uninterrupted voice communication.
Dedicated DSP Architecture
With 21 DSP cores distributed across seven SP2603 chips, the SPA-DSP provides hardware-accelerated voice processing independent of the router's main CPU. This dedicated architecture delivers low-latency media handling and prevents voice quality degradation under heavy traffic loads.
Transrating & DTMF Interworking
Beyond codec translation, the SPA-DSP handles transrating — converting between different packetization intervals — and DTMF interworking for reliable tone signaling across diverse VoIP environments. These capabilities are essential for service provider peering and multi-vendor enterprise deployments.
Hot-Swappable SPA Form Factor
The half-height, single-width SPA design supports online insertion and removal (OIR), allowing field replacement without taking the router offline. This is critical for carrier-grade environments where uptime SLAs demand non-disruptive maintenance windows.
SBC & CUBE Integration
The SPA-DSP works in conjunction with the Cisco SBC application and CUBE Enterprise (CUBE ENT) to provide end-to-end voice media processing. This tight integration simplifies deployment of SIP trunking, VoIP peering, and enterprise voice aggregation services on the ASR 1000 platform.
Deployment Scenarios
Service Provider VoIP Peering
At carrier interconnect points, the SPA-DSP enables real-time codec transcoding and transrating between peering partners using different codec standards. This ensures seamless voice quality across network boundaries while the SBC handles session signaling and policy enforcement.
Enterprise SIP Trunking Aggregation
Large enterprises consolidating voice traffic onto ASR 1000 routers benefit from the SPA-DSP's ability to transcode between internal UC codecs and service provider trunk requirements. The module handles DTMF interworking to maintain reliable IVR and conferencing functionality.
Managed Voice Services Edge
Managed service providers deploying ASR 1000 routers at the customer edge can use the SPA-DSP to normalize diverse customer codec profiles into a standard backbone codec, reducing bandwidth consumption and simplifying network-wide voice quality management.
General
Performance
Connectivity
Physical
Environmental
Compliance
Warranty & Lifecycle
Compatibility Notes
Compatible Platforms
The SPA-DSP is designed for the following Cisco ASR 1000 Series routers:
- ASR 1001
- ASR 1002 / ASR 1002-X / ASR 1002-F
- ASR 1004
- ASR 1006
- ASR 1013
Required SPA Interface Processors
- ASR1000-SIP10
- ASR1000-SIP40
Compatible Embedded Services Processors
- ASR1000-ESP10
- ASR1000-ESP40
- ASR1000-ESP100
Compatible Route Processors
- ASR1000-RP1
- ASR1000-RP2
Minimum Software
- Cisco IOS XE Release 3.2S or later
End-of-Life Notice
The SPA-DSP reached End-of-Sale on May 1, 2020 (Cisco EoL bulletin EOL13418). Units are available through the secondary/refurbished market.
Downloads & Resources
Frequently Asked Questions
| Part Number | Product | Key Difference |
|---|---|---|
| PVDM3-192 | Cisco 192-Channel Voice/Video DSP Module | DIMM-based DSP for ISR G2 routers; lower density than SPA-DSP but suited for branch/campus deployments |
| PVDM4-256 | Cisco 256-Channel Voice DSP Module | Next-gen PVDM4 DSP for ISR 4000 Series; higher per-module density with newer codec support |
| SPA-DSP= | Cisco SPA-DSP (Orderable SKU) | Same module as SPA-DSP; the '=' suffix denotes the separately orderable spare part number |