Table Of Contents
Release Notes for Cisco MWR 1900 Mobile Wireless Edge Router for Cisco IOS Release 12.2(8)MC2
July 29, 2002
Cisco IOS Release 12.2(8)MC2
These release notes are for the Cisco MWR 1900 Mobile Wireless Edge Router for Cisco IOS Release 12.2(8)MC2.These release notes are updated as needed to describe new features, memory requirements, hardware support, software platform deferrals, and changes to the microcode and related documents.
For a list of the software caveats that apply to Cisco IOS Release 12.2(8)MC2, see the "Caveats in Cisco IOS Release 12.2(8)MC2" section.
To review the release notes for Cisco IOS Release 12.2, go to www.cisco.com and click Technical Documents. Select Release 12.2 from the Cisco IOS Software drop-down menu. Then click Cisco IOS Release Notes > Cisco IOS Release 12.2.
This document contains the following sections:
The Cisco MWR 1900 Mobile Wireless Edge Router running Cisco IOS Release 12.2(8) MC2 or a later Cisco IOS Release 12.2 MC is a networking platform optimized for use in mobile wireless networks. It extends IP connectivity to the cell site and Base Transceiver Station (BTS), and through a Fast Ethernet interface to the BTS, provides bandwidth-efficient IP transport of voice and data bearer traffic, as well as maintenance, control, and signalling traffic, over the leased line backhaul network between the BTS and leased line termination and aggregation node via compression (cRTP/cUDP) and packet multiplexing (PPPMux and MLPPP). It supports a limited set of interfaces and protocols, but offers high performance at a low cost while meeting the critical requirements for deployment in cell sites, including small size, extended operating temperature range, high availability, and DC input power flexibility.
System Configuration Requirements
The Cisco MWR 1900 Mobile Wireless edge router requires the following system configuration:
•Cisco IOS 12.2(8) MC2 or a later Cisco IOS Release 12.2 MC Software be installed.
•Network Time Protocol (NTP)
Network Time Protocol must be configured. The Cisco MWR 1900 router uses NTP to maintain a clocking source for the proper time stamping of system messages and log files.
When not using the Cisco MWR 1900 router in a redundant configuration, the standalone option must be configured from redundancy mode.
When using the Cisco MWR 1900 router in a redundant configuration, the keepalives under the FE must be set to 1.
Table 1 Memory Recommendations for the Cisco MWR 1900 Mobile Wireless Edge Router
Platform Software Image Flash
Cisco MWR 1900 Mobile Wireless Edge Router
32 MB Flash
128 MB DRAM
Determining the Software Version
To determine the version of Cisco IOS software running on your Cisco MWR 1900 router, log in to the Cisco MWR 1900 and enter the show version EXEC command:router> show versionCisco Internetwork Operating System SoftwareIOS (tm) 1900 Software (MWR1900-I-MZ), Version 12.2(8)MC2, EARLY DEPLOYMENT RELEASESOFTWARE (fc1)
Upgrading to a New Software Release
For general information about upgrading to a new software release, refer to Software Installation and Upgrade Procedures located at the following URL:
New Features in the Cisco MWR 1900 Router with Cisco Release 12.2 MC Software
The software running on the Cisco MWR 1900 router consists of two components: Cisco IOS software running on the MIPs-based route processor portion of the router hardware, and microcode running on the Cisco network processor, also known as Parallel eXpress Forwarding (PXF). Because the Cisco MWR 1900 router is designed specifically for use in an IP-RAN in the BTS, it is customized for performance, high-availability, quality of service, and link efficiency.
For detailed descriptions of each of these features, see the Cisco MWR 1900 Mobile Wireless Edge Router Software Configuration Guide.
•Cisco IOS Software Features
Cisco IOS software function added for the Cisco MWR 1900 router IP-RAN application include:
Standard Cisco IOS software features supported in this release include:
–MLP, PPP Control Path (IPCP, NCP, LCP, CLNS)
•Network Processor Software
The following features are supported in the network processor:
–MLP, PPP Data Path (MLP LFI is not supported)
•Cisco Hot Standby Router Protocol (HSRP) support
Limitations, Restrictions, and Important Notes
Caution The Cisco MWR 1900 router does not support online insertion and removal (OIR) of WAN interface cards. Any attempt to perform OIR on a card in a powered up router might cause damage to the card.
Caution Removing the compact flash from the Cisco MWR 1900 router during a read/write operation might corrupt the contents of the compact flash, rendering it useless. To recover from an accidental removal of or corruption to the compact flash, a maintenance spare with the appropriate bootable Cisco IOS software image might be needed.
Unsupported Cisco IOS Software Features
The Cisco MWR 1900 router requires a special version of Cisco IOS software. Not all Cisco IOS software features can be used with the Cisco MWR 1900 router as the core routing is handled by the network processor. The following standard Cisco IOS software features are not supported on the Cisco MWR 1900 router:
•Security Access Control Lists
•Frame Relay (FR)
Upgrading the VWIC-2MFT-T1-DIR Microcode
When upgrading the image on your Cisco MWR 1900 router, power cycle the router or perform a microcode reload on the VWIC-2MFT-T1-DIR to ensure that the firmware for the VWIC-2MFT-T1-DIR is updated during the upgrade.
Disabling PPP Multiplexing
To fully disable PPP multiplexing (PPPMux), issue the no ppp mux command on the T1 interfaces of the routers at both ends of the T1 link. If PPP multiplexing remains configured on one side of the link, that side will offer to receive PPP multiplexed packets.
MLP LFI Support
MLP LFI is not supported by the Cisco MWR 1900 router. Therefore, MLP LFI must be disabled on peer devices connecting to the Cisco MWR 1900 router T1 MLP connections.
Caveats in Cisco IOS Release 12.2(8)MC2
The following sections list and describe the open and closed caveats for the Cisco MWR 1900 router running Cisco IOS Release 12.2(8)MC2. Only severity 1 through 3 caveats are included.
Caveats describe unexpected behavior in Cisco IOS software releases. Severity 1 caveats are the most serious caveats, severity 2 caveats are less serious, and severity 3 caveats are the least serious of these three severity levels.
Caveats in Cisco IOS Releases 12.2 and 12.2 T are also in Cisco IOS Release 12.2(8)MC2. For information on caveats in Cisco IOS Release 12.2, see Caveats for Cisco IOS Release 12.2. For information on caveats in Cisco IOS Release 12.2 T, see Caveats for Cisco IOS Release 12.2 T. These two documents list severity 1 and 2 caveats and are located on CCO and the Documentation CD-ROM.
Note If you have an account with Cisco.com, you can use Bug Navigator II to find caveats of any severity for any release. To reach Bug Navigator II, Login to Cisco.com and click Software Center: Cisco IOS Software: Cisco Bugtool Navigator II. Another option is to go directly to http://www.cisco.com/support/bugtools.
The caveats listed in this section are open in Release 12.2(8)MC2.
When using an extended ACL with the access-group command to define traffic using the class policy-map configuration command, the Cisco MWR 1900 router crashes to ROMmon. This condition happens because extended ACLs are currently not supported.
Workaround: The access-group command is not part of the IP-RAN configuration. However, if using the command, use only with standard ACLs.
When traffic shaping is applied to an MLP output interface, the shaped output rate might be slightly higher than that defined. This condition occurs because the data rate to that interface is greater than the shaping rate.
Workaround: There is currently no workaround.
An MLP bundle might occasionally have a few inactive links. This condition causes the bandwidth of the multilink bundle to be incorrect for the number of T1 interfaces configured. This condition occurs when one or more T1 links of an MLP bundle have their encapsulation changed to PPP (Encapsulation Type 5) instead of MLP (Encapsulation type 12).
Workaround: Issue a shut/no shut of the multilink bundle to cause the inactive links to become active links of the bundle.
When the class-default queue is used with other class-based queues, the class-default queue's committed information rate (CIR) and the excess information rate are not configured correctly.
Workaround: Manually configure the committed information rate using the shape class-map configuration command. The excess information rate cannot be manually configured, therefore, there is no workaround for it not configuring correctly.
QoS class-based WFQs configured with a low percentage of bandwidth are unable to use the unused bandwidth from queues assigned a high percentage of the bandwidth.
Workaround: Deconfigure QoS on the output interface.
The caveats listed in this section are resolved in Release 12.2(8)MC2.
The PXF locks up, I/O memory lowers, and a CPU exception occurs when removing a serial link from an MLP bundle while bi-directional traffic is being processed.
When using MLP as the transport protocol, the PPP multiplexing ratio is less than expected when small packets are received. This condition occurs under normal operation (with cUDP and 18-bytes payload). The occurrence of multiple traffic flows that are in separate QoS classes might add to this condition.
When cUDP and PPP multiplexing/demultiplexing are enabled and startup occurs during a period of heavy UDP traffic, valid cUDP traffic flow might be corrupted in the PXF.
When PPP multiplexing/demultiplexing and cUDP are configure on an MLP bundle and a very small number of UDP traffic flows are sent from the MWR 1900 router to the MGX, occasionally a couple of packets on a flow might be dropped at the MGX because they were sent in the incorrect order by the MWR 1900 router.
When QoS (Low latency queueing [LLQ]/class-based WFQ [CBWFQ]) is configured on an output interface, drops might occur before they should on the priority queue during periods of high data rates.
When keepalive is enabled on a serial interface, the interface might alternate between an up and down state during heavy traffic conditions.
Collecting Data for Router Issues
To collect data for reporting router issues, issue the following command:
•show tech-support—Displays general information about the router when it reports a problem.
Collecting Data for Redundancy Issues
To collect data for redundancy-related issues, issue the following commands while in EXEC mode:
•show redundancy—Displays current or historical status and related information on redundant Dial Shelf Controllers (DSCs).
•show controllers—Displays information that is specific to the hardware.
•show standby—Displays Hot Standby Router Protocol (HSRP) information.
•show ip interface—Displays the usability status of interfaces configured for IP.
Collecting Data for ROMmon Issues
To collect data for ROMmon issues, issue the following command while in EXEC mode:
•showmon— Displays currently selected ROM monitor.
Collecting Data for Router Rebooting to ROMmon
If a router reboot to ROMmon occurs, issue the dir device ID command where device ID is slot0:, and look for the router processor or network processor exception file (crashinfo* or pxf_crashinfo* respectively). Once you have located one of these files, you can email the file along with a description of the problem to your Cisco representative.
There are no documentation updates at this time.
The following sections describe the documentation available for the Cisco MWR 1900 Mobile Wireless Edge Router. These documents consist of hardware and software installation guides, Cisco IOS configuration guides and command references, system error messages, and other documents.
Documentation is available as printed manuals or electronic documents.
These documents are available for the Cisco MWR 1900 Mobile Wireless Edge Router on Cisco.com and the Documentation CD-ROM:
•Cisco MWR 1900 Mobile Wireless Edge Router
–Cisco MWR 1900 Hardware Installation Guide
–Cisco MWR 1900 Software Configuration Guide
–Cisco MWR 1900 Rack Mounting Instructions
–Cisco MWR 1900 Regulatory Compliance and Safety Information
•VWIC-2MFT-T1-DIR, VWIC-2MFT-E1-DIR Installation Instructions
•MGX-RPM-1FE-CP Back Card Installation and Configuration Note
On Cisco.com at:
Technical Documents: Cisco Product Documentation: Fixed and Mobile Wireless Solution: Cisco Mobile Wireless IP-RAN: Cisco Mobile Wireless IP-RAN Version 1.0
On the Documentation CD-ROM at:
Cisco Product Documentation: Fixed and Mobile Wireless Solution: Cisco Mobile Wireless IP-RAN: Cisco Mobile Wireless IP-RAN Version 1.0
Feature modules describe new features supported by Cisco IOS Release 12.2 MC and are updates to the Cisco IOS documentation set. A feature module consists of an overview of the feature, configuration tasks, and a command reference.
On Cisco.com at:
Technical Documents: Cisco IOS Software: Cisco IOS Release 12.2: New Feature Documentation: New Features in 12.2-Based Limited Lifetime Releases: New Features in Release 12.2 MC: New Features in Release 12.2 MC2
On the Documentation CD-ROM at:
Cisco Product Documentation: Cisco IOS Software Configuration: Cisco IOS Release 12.2: New Feature Documentation: New Features in 12.2-Based Limited Lifetime Releases: New Features in Release 12.2 MC: New Features in Release 12.2 MC2
These sections explain how to obtain documentation from Cisco Systems.
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Obtaining Technical Assistance
Cisco provides Cisco.com as a starting point for all technical assistance. Customers and partners can obtain online documentation, troubleshooting tips, and sample configurations from online tools by using the Cisco Technical Assistance Center (TAC) Web Site. Cisco.com registered users have complete access to the technical support resources on the Cisco TAC Web Site.
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Technical Assistance Center
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•Priority level 3 (P3)—Your network performance is degraded. Network functionality is noticeably impaired, but most business operations continue.
•Priority level 2 (P2)—Your production network is severely degraded, affecting significant aspects of business operations. No workaround is available.
•Priority level 1 (P1)—Your production network is down, and a critical impact to business operations will occur if service is not restored quickly. No workaround is available.
The Cisco TAC resource that you choose is based on the priority of the problem and the conditions of service contracts, when applicable.
Cisco TAC Web Site
You can use the Cisco TAC Web Site to resolve P3 and P4 issues yourself, saving both cost and time. The site provides around-the-clock access to online tools, knowledge bases, and software. To access the Cisco TAC Web Site, go to this URL:
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If you are a Cisco.com registered user, and you cannot resolve your technical issues by using the Cisco TAC Web Site, you can open a case online by using the TAC Case Open tool at this URL:
If you have Internet access, we recommend that you open P3 and P4 cases through the Cisco TAC Web Site.
Cisco TAC Escalation Center
The Cisco TAC Escalation Center addresses priority level 1 or priority level 2 issues. These classifications are assigned when severe network degradation significantly impacts business operations. When you contact the TAC Escalation Center with a P1 or P2 problem, a Cisco TAC engineer automatically opens a case.
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This document is to be used in conjunction with the documents listed in the "Related Documentation" section.
Copyright © 2002, Cisco Systems, Inc.
All rights reserved.