Release Notes for Cisco MWR 1941-DC Mobile Wireless Edge Router for Cisco IOS Release 12.2(15)MC2
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Table Of Contents
Release Notes for Cisco MWR 1941-DC Mobile Wireless Edge Router for Cisco IOS Release 12.2(15)MC2
System Configuration Requirements
Determining the Software Version
Upgrading to a New Software Release
Upgrading to a New ROM Monitor Version
New Features in the Cisco IOS Release 12.2(15)MC2
New Features in the Cisco IOS Release 12.2(15)MC1
Ignoring the IP ID in RTP/UDP Header Compression
Configuring ACFC and PFC Handling During PPP Negotiation
Configuring the cUDP Flow Expiration Timeout Duration
Limitations, Restrictions, and Important Notes
Caveats in Cisco IOS Release 12.2(15)MC2
Configuring RTP/UDP Compression
The show ip rtp header-compression Command
Obtaining Technical Assistance
Release Notes for Cisco MWR 1941-DC Mobile Wireless Edge Router for Cisco IOS Release 12.2(15)MC2
May 20, 2004
Cisco IOS Release 12.2(15)MC2
OL-13984-09
These release notes are for the Cisco MWR 1941-DC Mobile Wireless Edge Router for Cisco IOS Release 12.2(15)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(15)MC2, see the "Caveats in Cisco IOS Release 12.2(15)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.
Contents
This document contains the following sections:
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System Configuration Requirements
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Introduction
The Cisco MWR 1941-DC Mobile Wireless Edge Router running Cisco IOS Release 12.2(15) MC2 software 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
When being implemented in a Cisco IP Radio Access Network (IP-RAN) solution, the Cisco MWR 1941-DC router requires the following system configuration:
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Network Time Protocol must be configured. The Cisco MWR 1941-DC router uses NTP to maintain a clocking source for the proper time stamping of system messages and log files.
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When not using the Cisco MWR 1941-DC router in a redundant configuration, the standalone option must be configured from redundancy mode.
When using the Cisco MWR 1941-DC router in a redundant configuration:
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You cannot disable Cisco Express Forwarding (CEF) on the MWR 1941-DC. Commands such as no ip cef will display an error message "%Cannot disable CEF on this platform." Some commands, such as no ip route-cache cef, will not return an error message, however, CEF will not be disabled regardless of whether or not an error message is displayed.
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In case of a tie in priority, HSRP uses the IP address to determine the active router. Therefore, you should ensure that the order of the IP addresses of the E1/T1 interfaces of the active router corresponds to the order of the IP addresses of the E1/T1 interfaces of the standby router.
Memory Recommendations
Determining the Software Version
To determine the version of Cisco IOS software running on your Cisco MWR 1941-DC router, log in to the Cisco MWR 1941-DC and enter the show version EXEC command:
router> show versionCisco Internetwork Operating System SoftwareIOS (tm) 1900 Software (MWR1900-I-MZ), Version 12.2(15)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:
http://www.cisco.com/warp/public/130/upgrade_index.shtml
Upgrading to a New ROM Monitor Version
The Cisco MWR 1941-DC router ROM Monitor (ROMMON) consists of two modules:
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To upgrade the ROMMON version on your Cisco MWR 1941-DC router, complete these steps from EXEC mode:
Step 1
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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.122-8r.MC3Step 3
Router# upgrade rom-monitor file slot0:MWR1900_RM2.srec.122-8r.MC3This command will reload the router. Continue? [yes/no]:yStep 4
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 and Changed Information
The following sections list the new hardware and software features supported by the Cisco MWR 1941-DC router for Cisco IOS Release 12.2(15)MC software.
New Features in the Cisco IOS Release 12.2(15)MC2
No features are introduced in Cisco IOS Release 12.2(15)MC2.
New Features in the Cisco IOS Release 12.2(15)MC1
The following features were introduced in Cisco IOS Release 12.2(15)MC1:
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For information on new features in previous Cisco IOS Release 12.2MC software releases, see the platform release notes:
http://www.cisco.com/univercd/cc/td/doc/product/wireless/ipran/1_0/relnotes/index.htm
Ignoring the IP ID in RTP/UDP Header Compression
With Cisco IOS Release 12.2(8)MC2c, IP ID checking was suppressed in RTP/UDP header compression. With Cisco IOS Release 12.2(15)MC1, a new option has been added to the ip rtp header-compression interface configuration command that allows you to enable or suppress this checking. The default is to suppress.
To suppress IP ID checking, issue the following command while in interface configuration mode:
Router(config-if)# ip rtp header-compression ignore-id
Suppresses the IP ID checking in RTP/UDP header compression.
To restore IP ID checking, use the no form of this command.
This new feature is identified by CSCdz75957.
Configuring ACFC and PFC Handling During PPP Negotiation
With Cisco IOS 12.2(15)MC1, ACFC and PFC handling during PPP negotiation can be configured.
Configuring ACFC Handling During PPP Negotiation
Use the following commands beginning in global configuration mode to configure ACFC handling during PPP negotiation:
Configuring PFC Handling During PPP Negotiation
Use the following commands beginning in global configuration mode to configure PFC handling during PPP negotiation:
To restore the default, use the no forms of these commands.
Note
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122limit/122b/122b_15/12b_acf.htm#1025043
Configuring the cUDP Flow Expiration Timeout Duration
To minimize traffic flow corruption, cUDP flows now expire after an expiration timeout duration during which no packets are passed. When this duration of inactivity occurs on a flow at the compressor, the compressor sends a full header upon receiving a packet for that flow, or, if no new packet are received for that flow, makes the CID for the flow available for new use. When a packet is received at the decompressor after the duration of inactivity, the packet is dropped and a context state message is sent to the compressor requesting a flow refresh.
The default expiration timeout is 5 seconds. The recommended value is 8 seconds.
Caution
To configure the cUDP flow expiration timeout duration, issue the following command while in multilink interface configuration mode:
Router(config-if)# ppp iphc max-time seconds
Specifies the duration of inactivity, in seconds, that when exceeded causes the cUDP flow to expire. The recommended value is 8.
To restore the default, use the no form of this command.
This new feature is identified by CSCeb44623.
Limitations, Restrictions, and Important Notes
Caution
Caution
Unsupported Cisco IOS Software Features
The Cisco MWR 1941-DC router requires a special version of Cisco IOS software. Not all Cisco IOS software features can be used with the Cisco MWR 1941-DC 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:
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Upgrading the VWIC-2MFT-T1-DIR Microcode
When upgrading the image on your Cisco MWR 1941-DC 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 1941-DC router. Therefore, MLP LFI must be disabled on peer devices connecting to the Cisco MWR 1941-DC 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 1941-DC routers connected to the MGX-RPM-1FE-CP back card.
Caveats in Cisco IOS Release 12.2(15)MC2
The following sections list and describe the open and closed caveats for the Cisco MWR 1941-DC router running Cisco IOS Release 12.2(15)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(15)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.
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Open Caveats
The caveats listed in this section are open in Cisco IOS Release 12.2(15)MC2.
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When using an extended ACL with the access-group command to define traffic using the class policy-map configuration command, the Cisco MWR 1941-DC 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.
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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.
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During periods of heavy multicast traffic (approximately 5000 pps), some multicast packets are dropped at the MWR 1941-DC MLP interface.
Workaround: Reduce the rate of multicast traffic.
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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 1941-DC IOS decompression.
Workaround: Reduce the rate of multicast traffic.
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Periods of sustained mixed traffic (UDP multicast, IP, and TCP) might cause the MWR 1941-DC router to crash.
Workaround: There is currently no workaround.
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During a failover, the MWR 1941-DC router software opens T1/E1 relays on the active router without taking down the multilink interface first. Packets are sent to the disconnected interface for the next several second until the multilink interface is declared down. This condition causes the network management system to not receive SNMP traps generated during the failover.
Workaround: There is currently no workaround.
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ifOperStatus displays an incorrect value for PPP encapsulated serial interfaces. The serial interface and line protocol are up (verified issuing the show interfaces serial command), however, the ifOperStatus is displayed as "notPresent(6)" instead of "up(1)".
Workaround: There is currently no workaround.
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Because they are not populated correctly, the cHsrpExtIfTrackedTable and cHsrpExtIfTable return null values when queried.
Workaround: Issue the show standby fastEthernet 0/0 command on the MWR 1941-DC router.
Closed or Resolved Caveats
This section lists the caveats that are closed or resolved in Release 12.2(15)MC1.
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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.
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QoS class-based WFQs configured with a low percentage of bandwidth cannot use the unused bandwidth from queues assigned a high percentage of the bandwidth.
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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."
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After a PXF crash on the MWR 1941-DC router and the PXF is restarted, traffic flowing over the bundle is sent with two MLP headers. The aggregation router will drop all received traffic. This condition does not affect traffic flowing from the bundle to the FE interface.
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The Cisco MWR 1941-DC router will enclose the host name within quotes in the configuration if the hostname hostname command is configured.
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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.
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Tail drops and output queue drops occur at traffic rates of mixed traffic of 6000 pps over a 4 T1 WAN link.
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Cisco routers and switches running Cisco IOS software and configured to process Internet Protocol version 4 (IPv4) packets are vulnerable to a Denial of Service (DoS) attack. A rare sequence of crafted IPv4 packets sent directly to the device may cause the input interface to stop processing traffic once the input queue is full. No authentication is required to process the inbound packet. Processing of IPv4 packets is enabled by default. Devices running only IP version 6 (IPv6) are not affected. A workaround is available.
Cisco has made software available, free of charge, to correct the problem.
This advisory is available at
http://www.cisco.com/warp/public/707/cisco-sa-20030717-blocked.shtml
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Cisco routers and switches running Cisco IOS software and configured to process Internet Protocol version 4 (IPv4) packets are vulnerable to a Denial of Service (DoS) attack. A rare sequence of crafted IPv4 packets sent directly to the device may cause the input interface to stop processing traffic once the input queue is full. No authentication is required to process the inbound packet. Processing of IPv4 packets is enabled by default. Devices running only IP version 6 (IPv6) are not affected. A workaround is available.
Cisco has made software available, free of charge, to correct the problem.
This advisory is available at
http://www.cisco.com/warp/public/707/cisco-sa-20030717-blocked.shtml
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The Line Error Seconds counter under the VWIC-MFT show controller t1/e1 command output keeps incrementing when switched to UnAvailable Seconds after 10 Severely Errored Seconds.
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The MWR 1941-DC router might crash during channel-group provisioning.
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All multicast traffic outbound to the MLP interface is incorrectly scheduled for only one of the 4 T1s which are active members of the bundle. This condition causes multicast traffic above that one T1's bandwidth to be dropped.
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When Qmax is set to an arbitrary number (non power of 2), it is being set to the closest power of 2 rather than the smallest power of 2 to sufficient to support the Qlimit.
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When sending non PXF-handled traffic (for example, uncompressed, unfragmented, non-multicast Fast Ethernet traffic) the Fast Ethernet total input byte count is incorrect.
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When configuring a T1 channel group, serial interfaces appear fine, MLP interface is UP/UP, but there is no WAN connectivity.
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When the FE0/1 interface cabling is disconnected on the active router in a redundant configuration, the routers might attempt, but not complete, to swap roles. This causes the VWIC interface WAN connection relays to be left open, which results in both routers losing WAN connectivity.
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Upon deleting a channel group, tracebacks might occur at "process_ok_to_reschedule" and traffic might not pass through even though the interface is up and the routes exist.
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SNMP query of ciscoFlashDeviceSize returns 0.
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The cardSerial and cardSlots MIB variables display the wrong values.
Troubleshooting
Collecting Data for Router Issues
To collect data for reporting router issues, issue the following command:
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Collecting Data for Redundancy Issues
To collect data for redundancy-related issues, issue the following commands while in EXEC mode:
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Collecting Data for ROMmon Issues
To collect data for ROMmon issues, issue the following command while in EXEC mode:
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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.
Documentation Updates
The following sections describe updates to the published documentation for the Cisco MWR 1941-DC router. 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 change 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 it is specified in command.
Configuring T1 Interfaces
Some configuration modes shown in the procedure for configuring T1 interfaces in the "Configuring T1 Interfaces" of the Cisco MWR 1900 Software Configuration Guide are incorrect. The correct command modes are as follows:
Step 1
Router(config)# controller t1 slot/portStep 2
Router(config-controller)# framing esfStep 3
Router(config-controller)# linecode b8zsStep 4
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Router(config-controller)# channel-group 0 timeslots 1-24 speed 64Step 5
Router(config-controller)# cablelength feet
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Step 6
Router(config-controller)# exitStep 7
Router(config)# interface serial slot/port:0Step 8
Router(config-if)# ip address ip_address subnet_maskStep 9
Router(config-if)# encapsulation pppStep 10
Router(config-if)# carrier-delay numberStep 11
Step 12
Router(config-if)# exit
Configuring Redundancy
Before configuring redundant MWR 1941-DC routers as described in the "Configuring T1 Interfaces" section of the Cisco MWR 1900 Software Configuration Guide, ensure that you disable EADI capabilities on the router by issuing the disable-eadi global configuration command as follows:
Router(config)# disable-eadiRelated Documentation
The following sections describe the documentation available for the Cisco MWR 1941-DC 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.
Platform-Specific Documents
These documents are available for the Cisco MWR 1941-DC router on Cisco.com and the Documentation CD-ROM:
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On Cisco.com at:
Technical Documents: Wireless: Mobile Wireless Products: Cisco Radio Access Network Products: Cisco Mobile Wireless IP-RAN
On the Documentation CD-ROM at:
Wireless: Mobile Wireless Products: Cisco Radio Access Network Products: Cisco Mobile Wireless IP-RAN
Feature Modules
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
Obtaining Documentation
These sections explain how to obtain documentation from Cisco Systems.
World Wide Web
You can access the most current Cisco documentation on the World Wide Web at this URL:
Translated documentation is available at this URL:
http://www.cisco.com/public/countries_languages.shtml
Documentation CD-ROM
Cisco documentation and additional literature are available in a Cisco Documentation CD-ROM package, which is shipped with your product. The Documentation CD-ROM is updated monthly and may be more current than printed documentation. The CD-ROM package is available as a single unit or through an annual subscription.
Ordering Documentation
You can order Cisco documentation in these ways:
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http://www.cisco.com/cgi-bin/order/order_root.pl
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http://www.cisco.com/go/subscription
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Documentation Feedback
You can submit comments electronically on Cisco.com. In the Cisco Documentation home page, click the Fax or Email option in the "Leave Feedback" section at the bottom of the page.
You can e-mail your comments to bug-doc@cisco.com.
You can submit your comments by mail by using the response card behind the front cover of your document or by writing to the following address:
Cisco Systems
Attn: Document Resource Connection
170 West Tasman Drive
San Jose, CA 95134-9883We appreciate your comments.
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.
Cisco.com
Cisco.com is the foundation of a suite of interactive, networked services that provides immediate, open access to Cisco information, networking solutions, services, programs, and resources at any time, from anywhere in the world.
Cisco.com is a highly integrated Internet application and a powerful, easy-to-use tool that provides a broad range of features and services to help you with these tasks:
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If you want to obtain customized information and service, you can self-register on Cisco.com. To access Cisco.com, go to this URL:
Technical Assistance Center
The Cisco Technical Assistance Center (TAC) is available to all customers who need technical assistance with a Cisco product, technology, or solution. Two levels of support are available: the Cisco TAC Web Site and the Cisco TAC Escalation Center.
Cisco TAC inquiries are categorized according to the urgency of the issue:
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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
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:
All customers, partners, and resellers who have a valid Cisco service contract have complete access to the technical support resources on the Cisco TAC Web Site. The Cisco TAC Web Site requires a Cisco.com login ID and password. If you have a valid service contract but do not have a login ID or password, go to this URL to register:
http://www.cisco.com/register/
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:
http://www.cisco.com/tac/caseopen
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.
To obtain a directory of toll-free Cisco TAC telephone numbers for your country, go to this URL:
http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml
Before calling, please check with your network operations center to determine the level of Cisco support services to which your company is entitled: for example, SMARTnet, SMARTnet Onsite, or Network Supported Accounts (NSA). When you call the center, please have available your service agreement number and your product serial number.
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