http://www.cisco.com/c/en/us/products/collateral/routers/asr-1000-series-aggregation-services-routers/qa_C67-443177.html
"Q. What are the main differences between the SIP10 and SIP40?
A. The main difference is that the SIP40 enables 40 Gbps aggregate bandwidth per slot, while the SIP10 provides 10 Gbps of aggregate bandwidth per slot."
