RP0: ROMMON Version: 16.4(1r) [or 173-1r] ESP0: ROMMON Version: 16.4(1r) Or, during boot, watch for:
Introduction: The Silent Guardian of Your ASR 1000 In the world of enterprise and service provider networking, the Cisco ASR 1000 series stands as a workhorse for aggregation, WAN edge, and broadband access. While network engineers spend most of their time worrying about IOS XE versions, feature sets, and license levels, there is one tiny, often overlooked file that holds the power to resurrect a bricked router: asr1000-rommon.173-1r.spa.pkg . asr1000-rommon.173-1r.spa.pkg
show platform show rom-monitor RP0 show rom-monitor ESP0 Look for output like: RP0: ROMMON Version: 16
This seemingly cryptic filename is the for the ASR 1000 series. If your ASR 1002, 1004, or 1006 router suffers a corrupted bootflash, a failed field-replaceable unit (FRU), or a catastrophic IOS crash, the ROMMON is the first code that executes. Without the correct, updated ROMMON, your router might fail to boot or, worse, fail to recover via USB or TFTP. If your ASR 1002, 1004, or 1006 router
This specific file is not a full IOS XE image. It is a that lives on the motherboard’s boot flash, separate from the main disk. Part 2: Why is ROMMON Version 173-1r Critical? The jump to 173-1r was not minor. Previous ROMMON versions (like 16.x or 122-8r) lacked critical support for modern boot scenarios. Here is what 173-1r introduced or fixed: 2.1. Support for Larger Bootflash Devices Early ASR 1000 units had 4GB bootflash. Modern IOS XE images easily exceed 1GB, and 173-1r improved the ROMMON’s file system driver to handle 8GB, 16GB, and even 32GB USB drives for recovery. 2.2. Enhanced USB Boot Capability In older ROMMON versions, booting via USB was unreliable. Version 173-1r added robustness to usb flash: commands, allowing engineers to recover a router with no console interruptions. 2.3. Fix for the "Boot Loop" Bug (CSCvx12345 – example) Several ASR 1004 units with ESPs were stuck in a power cycle loop when booting 17.x IOS XE. 173-1r included a patch to the hardware initialization sequence for the ESP-100 and ESP-200 cards. 2.4. Improved SPA Driver Handshake The .spa in the filename indicates better initialization of Shared Port Adapters (like 1-port 10GE or 8-port T1/E1) during boot, preventing "SPA not detected" errors. Part 3: Which ASR 1000 Platforms Use This File? The asr1000-rommon.173-1r.spa.pkg is compatible with all ASR 1000 series that use the SPA-based architecture and separate RP/ESP. Specifically:
| Component | Meaning | |-----------|---------| | | Platform family (ASR 1000 series – including ASR 1001-X, 1002-HX, 1004, 1006, etc.) | | rommon | ROMMON – the bootstrap firmware stored on the RP (Route Processor) or ESP (Embedded Services Processor) | | 173-1r | Version number: Major version 173, minor version 1, revision r (often indicates a rebuild or service pack) | | spa | Shared Port Adapter – though here, it indicates the package type for the SPA/driver environment | | pkg | Package file – the installable software bundle for the IOS XE ecosystem |