Table Of Contents
Release Notes for Cisco MWR 1900 Mobile Wireless Edge Router for Cisco IOS Release 12.2(8)MC2c
January 9, 2003
Cisco IOS Release 12.2(8)MC2c
These release notes are for the Cisco MWR 1900 Mobile Wireless Edge Router for Cisco IOS Release 12.2(8)MC2c. 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)MC2c, see the "Caveats in Cisco IOS Release 12.2(8)MC2c" 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:
Upgrading to a New ROM Monitor Version
The MWR 1900 ROM Monitor (ROMMON) consists of two modules:
•A resident module that is not changed during the upgrade procedure.
•An upgradable module that is updated during the upgrade procedure. This is the only module that you will download from Cisco.com.
Note Before performing this procedure, you must download the new ROMMON image from Cisco.com. The download procedure is the same as downloading Cisco IOS software images.
Note In the event of a power outage, the ROM monitor download will not be successful.
To upgrade the ROMMON version on your Cisco MWR 1900 router, complete these steps from EXEC mode:
Step 1 Copy the new ROMMON image from a TFTP server to slot0.
Step 2 Verify that the new image has been copied:Router#dir slot0:Directory of slot0:/3 -rw- 871 Mar 01 1993 00:05:02 MWR1900-3-default.cfg4 -rw- 610704 Mar 01 1993 00:10:30 MWR1900_RM2.srec
Step 3 Upgrade the current configuration by entering the upgrade rom-monitor command as shown in the following example:Router# upgrade rom-monitor file slot0:MWR1900_RM2.srecWilma-2#upgrade rom-monitor file slot0:MWR1900_RM2.srec.122-8r.MC3This command will reload the router. Continue? [yes/no]:y
Step 4 Press Enter to continue. The router begins downloading the ROMMON image. The router automatically reboots.ROMMON image upgrade in progressErasing boot flasheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeProgramming boot flash ppppNow ReloadingSystem Bootstrap, Version 12.2(20010915:181836) DEVELOPMENT SOFTWARECopyright (c) 1994-2001 by cisco Systems, Inc.Running new upgrade for first timeSystem Bootstrap, Version 12.2(8r)MC3, RELEASE SOFTWARE (fc1)TAC Support:http://www.cisco.com/tacCopyright (c) 2002 by cisco Systems, Inc.mwr1900 processor with 131072 Kbytes of main memoryMain memory is configured to 64 bit mode with parity disabledUpgrade ROMMON initializedrommon 1 >
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:
–MLPPP, MLP, PPP Data Path (MLP LFI is not supported)
•Cisco Hot Standby Router Protocol (HSRP) support
New Feature in Cisco IOS Release 12.2(8)MC2b Software
The following new feature is introduced in Cisco IOS Release 12.2(8)MC2b.
Traffic Recovery Over MLP After T1 Failure
When a T1 failure occurs, traffic recovers over the MLP link within 6 seconds.
This caveat is a feature enhancement to the keepalive interface configuration command. With this enhancement, you can also configure a maximum number of retries before a link is declared down by issuing the command as follows:
keepalive [interval] [retries]
•interval is the keepalive interval (in seconds). Valid value is a number greater than 0. The default is 10.
•retries is the number of times a link will be tried again before being declared down. Valid value is a number between 1 and 255. The default is 5.
For implementation in an IP RAN solution, the recommended configuration is as follows:
On the MWR 1900:interface Serial0/0:0no ip addressencapsulation pppkeepalive 1 2no cdp enableppp multilinkmultilink-group 1end
On the MGX-RPM-1FE-CP back card;interface Virtual-Template2bandwidth 1536no ip addresskeepalive 1 2no peer default ip addressppp multilinkmultilink-group 101end.
Note In the MGX-RPM-1FE-CP backcard configuration example, only the keepalive interface command and configuration recommendation is specific to implementation in an IP RAN solution.
This new feature is identified by CSCdy78207.
New Features in Cisco IOS Release 12.2(8)MC2c Software
These sections describe the new features in Cisco IOS Release 12.2(8)MC2c.
ACFC and PFC Support on PPP Interfaces
By default, Address and Control Field Compression (ACFC) and Protocol Field Compression (PFC) are enabled on PPP interfaces. Both features are always enabled and will be negotiated on all serial interfaces.
Note If upgrading for this support, ensure that you upgrade the MGX-RPM-1FE-CP backcard images first. After doing so, immediately upgrade all MWR 1900 routers connected to the MGX-RPM-1FE-CP back card.
This new feature is identified by CSCdz15365.
Ignore IP ID Field Delta in cUDP Packet Flows Support
By default, the ability to ignore IP ID field delta in cUDP traffic flows is enabled. This ability eliminates the need to send information about the IP header ID field in compressed packets. The decompressor saves the original ID field from the full header packet and generates an ID field by incrementing it by one for each decompressed packet.
This feature improves processing efficiency; helping to minimize dropped packets and link saturation.
This feature is identified by CSCdz00521.
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.
ACFC and PFC Support on PPP Interfaces
If upgrading to Cisco IOS Release 12.2(8)MC2c or later for the ACFC and PFC support on PPP interfaces, ensure that you upgrade the MGX-RPM-1FE-CP backcard image first. After doing so, immediately upgrade all MWR 1900 routers connected to the MGX-RPM-1FE-CP back card.
Caveats in Cisco IOS Release 12.2(8)MC2c
The following sections list and describe the open and closed caveats for the Cisco MWR 1900 router running Cisco IOS Release 12.2(8)MC2c. 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)MC2c. 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)MC2c.
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.
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.
When IOMEM is low, a PXF memory leak occurs when processing multicast traffic (into the FE and out the MLP interface).
Workaround: Use the memory-size iomem command to allocate, at minimum, 20 percent of the DRAM memory to I/O memory (for example, memory-size iomem 20).
During periods of heavy multicast traffic (approximately 5000 pps), some multicast packets are dropped at the MWR 1900 MLP interface.
Workaround: Reduce the rate of multicast traffic.
Entering or modifying the shape class-map configuration command to a policy map that has already been applied to an interface has no affect. Therefore, there will be no change to the traffic flow for that class of traffic. In addition, specifying certain values using the shape command might generate the message "Shape rate too low for interface."
Workaround: Remove the policy map from the interface and then reapply it, or save the new configuration and reload the router to get the changes to take effect. If the "Shape rate too low for interface" message displayed before, the value will be accepted and applied when one of the above methods is used.
When PPPMux and cUDP are configured, UDP fragmentation at traffic rates of 600 pps or more causes conditions such as dropped packets at the receiving MLP interface and tail drops at the receiving FE interface.
Workaround: There is currently no workaround.
When PPPMux and cUDP are configured, during periods of sustained multicast traffic at a rate of 100 pps or more causes a periodic "out-of-sequence" condition in the MWR 1900 IOS decompression.
Workaround: Reduce the rate of multicast traffic.
Tail drops and output queue drops occur at traffic rates of mixed traffic of 6000 pps over a 4 T1 WAN link.
Workaround: Reduce the UDP multicast packet rate to no more than 300 pps.
This section lists the caveats resolved in Release 12.2(8)MC2c.
The MWR 1900 router incorrectly flushes Type 5 link-state advertisements (LSAs). This condition might occur when the MWR 1900 is acting as a OSPF not-so-stubby area (NSSA) translator and autonomous system border router (ASBR). If a route that is being redistributed gets overwritten by an NSSA external route, then the MWR 1900 generates a Type 5 LSA and immediately flushes it.
When the BTS advertises reachability to a logical IP address over a physical IP address for which the MWR 1900 router does not have resolved ARP entry, the ARP request for the physical next hop address takes approximately 25 to 30 seconds to be generated. During this period of time, the MWR 1900 drops packets and the mobile call is dropped.
When cUDP is enabled on an MGX-RPM-1FE-CP and the RPM contains multiple multilink bundles, if some or all of the multilink interfaces flap, when they come up, the wrong IP and UDP headers might get placed on one or more of the cUDP traffic flows that were present before the interface went down.
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.
This section contains information that was not included or was documented incorrectly in the Cisco MWR 1900 Software Configuration Guide. The heading in this section corresponds with the applicable section title in the documentation.
Configuring RTP/UDP Compression
The maximum number of RTP header compression connections per MLP bundle is documented as 600 when in fact, up to 1000 connections are supported on an interface. This amendment also applies to the ip rtp header-compression command description.
The show ip rtp header-compression Command
The detail keyword is not supported in the show ip rtp header-compression command. Therefore, output does not display for the detail keyword if specified in command.
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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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
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