Ordering Cisco ASR 1000 Series Router Feature Licenses Software feature licenses are required to turn on services on Cisco ASR 1000 Series Routers, in addition to the appropriate Cisco IOS XE Software as described in the previous section. Currently, two types of feature licenses are available. Certain services require only a right-to-use (RTU) license, whereas other services require both an RTU license and one or more number-of-sessions licenses. All the licenses on the Cisco ASR 1000 Series (with some exceptions for the Cisco ASR 1001 licenses prior to Cisco IOS XE Software Release 3.6S; refer to the section “Ordering Cisco ASR 1001, ASR1001-X, and ASR 1002-X Series Feature Licenses”) are honor-based; that is, the licenses are not enforced through a product activation or license key Cisco IOS Software redundancy: The Cisco ASR 1000 Series Router software redundancy requires an RTU license (FLASR1-IOSRED-RTU(=) on ASR 1002; and FLSASR1-IOSRED(=) on ASR 1001, ASR 1001-X, and ASR 1002-X), which allows you to enable software redundancy on the Cisco ASR 1001, ASR 1002, ASR 1001-X, ASR 1002-X, and ASR 1004 chassis. Software redundancy requires 4-GB DRAM on the RP1, and 8-GB DRAM on the ASR 1001 or ASR 1002-X. The Cisco ASR 1001, ASR 1002, and ASR 1002-X come by default with 4-GB DRAM on the built-in route processor, and the ASR 1001-X comes by default with 8‑GB DRAM.