Release Notes for Cisco MWR 1941-DC Mobile Wireless Edge Router for Cisco IOS Release 12.2(15)MC2g
Available Languages
Table Of Contents
Release Notes for Cisco MWR 1941-DC Mobile Wireless Edge Router for Cisco IOS Release 12.2(15)MC2g
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)MC2g
New Features in the Cisco IOS Release 12.2(15)MC2f
New Features in the Cisco IOS Release 12.2(15)MC2e
New Features in the Cisco IOS Release 12.2(15)MC2b
New Features in the Cisco IOS Release 12.2(15)MC2a
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)MC2g
Caveats in Cisco IOS Release 12.2(15)MC2f
Caveats in Cisco IOS Release 12.2(15)MC2e
Caveats in Cisco IOS Release 12.2(15)MC2b
Caveats in Cisco IOS Release 12.2(15)MC2a
Configuring RTP/UDP Compression
The show ip rtp header-compression Command
Cisco Product Security Overview
Reporting Security Problems in Cisco Products
Obtaining Technical Assistance
Cisco Technical Support Website
Definitions of Service Request Severity
Obtaining Additional Publications and Information
Release Notes for Cisco MWR 1941-DC Mobile Wireless Edge Router for Cisco IOS Release 12.2(15)MC2g
April 19, 2006
Cisco IOS Release 12.2(15)MC2g
OL-13984-16
These release notes are for the Cisco MWR 1941-DC Mobile Wireless Edge Router for Cisco IOS Release 12.2(15)MC2g. 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)MC2g, see the "Caveats in Cisco IOS Release 12.2(15)MC2g" 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:
•
System Configuration Requirements
•
•
•
•
•
•
•
•
•
Introduction
The Cisco MWR 1941-DC Mobile Wireless Edge Router running Cisco IOS Release 12.2(15) MC2f 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 implemented in a Cisco IP Radio Access Network (IP-RAN) solution, the Cisco MWR 1941-DC router requires the following system configuration:
•
•
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.
•
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:
–
–
–
•
You cannot disable 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.
•
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)MC2a, 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/en/US/products/hw/routers/tsd_products_support_category_home.html
Upgrading to a New ROM Monitor Version
The Cisco MWR 1941-DC router ROM Monitor (ROMMON) consists of two modules:
•
•
Note
Note
Note
To upgrade the ROMMON version on your Cisco MWR 1941-DC router, complete these steps from EXEC mode:
Step 1
Step 2
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)MC2g
No features are introduced in Cisco IOS Release 12.2(15)MC2g.
New Features in the Cisco IOS Release 12.2(15)MC2f
No features are introduced in Cisco IOS Release 12.2(15)MC2f.
New Features in the Cisco IOS Release 12.2(15)MC2e
No features are introduced in Cisco IOS Release 12.2(15)MC2e.
New Features in the Cisco IOS Release 12.2(15)MC2b
No features are introduced in Cisco IOS Release 12.2(15)MC2b.
New Features in the Cisco IOS Release 12.2(15)MC2a
No features are introduced in Cisco IOS Release 12.2(15)MC2a.
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:
•
•
•
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:
•
•
•
•
•
•
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)MC2g
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)MC2g. 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)MC2g. 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 DVD.
Note
Open Caveats
There are no known open caveats in Cisco IOS Release 12.2(15)MC2g.
Resolved Caveats
This section lists the caveats that are resolved in Cisco Release 12.2(15)MC2g.
•
Description: Multicast packets are dropped by IOS until context is re-established.
This occurs during multicast on one flow at a rate of 100pps or more.
Workaround: Reduce the PPPMux subframe size on the RPM to a size smaller than a compressed multicast packet so that the multicast packets are not PPPMux'd.
•
Description: An RPM router running Cisco software release122-15.MC2e may drop multicast packets across a multilink interface if the ppp mux is configured on that interface.
Workaround: Reduce the PPPMux subframe size on the RPM to a size smaller than a compressed multicast packet so that the multicast packets are not PPPMux'd
Caveats in Cisco IOS Release 12.2(15)MC2f
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)MC2f. 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)MC2f. 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 DVD.
Note
Open Caveats
This section lists the caveats that are open in Cisco Release 12.2(15)MC2f.
•
Description: The MWFM or any other NMS system does not get important SNMP traps generated during failover. Up to 50% of the traps are lost.
During failover the Cisco MWR 1900 router software opens the T1/E1 relays on an active router without taking down the Multilink interface first. The Cisco MWR 1900 routing software keeps sending packets into the disconnected interface for the next few seconds until the interface Multilink goes down. Traps are sent and lost. Traps generated after the link is declared down are kept in the SNMP queue waiting to be routing in order to get restored.
Workaround: There is currently no workaround.
Resolved Caveats
This section lists the caveats that are resolved in Cisco Release 12.2(15)MC2f.
•
Description: The insertion of a GLI card to one of the Fast Ethernet (FE) ports of the Cisco MWR1900 router could cause the Multilink PPP interface to flap leading to a traffic outage for few seconds. A Hot Standby Routing Protocol (HSRP) swap over will also happen.
The Cisco MWR1900 routers are configured for HSRP redundancy and a GLI card insertion on the active Cisco MWR1900 router would cause the mlppp interface to go DOWN and come UP and would eventually cause the active Cisco MWR1900 router to become standby, and the standby router would then become the active router.
Workaround: There is no workaround to avoid the Multilink PPP interface from going down. However, to avoid HSRP swap over, the standby <number> preempt delay <seconds> commands can be configured. A value of 3 seconds is recommended.
Caveats in Cisco IOS Release 12.2(15)MC2e
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)MC2e. 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)MC2e. 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 DVD.
Note
Open Caveats
This section lists the caveats that are open in Cisco Release 12.2(15)MC2e.
•
Description: Frame slips were observed on port 0/1 if the T1 cable on port 0/0 was disconnected.
This situation occurs when the T1 cable connected to the first VWIC port (either port 0/0 or port 0/2) is pulled out from either the MWR side or the FRSM/MPSM side, and frame slips are seen on the remaining port in the same controller.
Workaround: Connect and disconnect the T1 cable according to following sequence:
1. Connect port 0/0 first and then port 0/1.
2. Disconnect port 0/1 first and then port 0/0
3. Perform the same procedure to ports 0/2 and 0/3.
Resolved Caveats
This section lists the caveats that are resolved in Release 12.2(15)MC2e.
•
Description: Mobile Wireless Fault Mediator (MWFM) or any other Network Management System (NMS) does not receive important Simple Network Management Protocol (SNMP) traps generated during failover. Up to 50% of the traps are lost.
During failover, the MWR 1900 routing software opens T1/E1 relays on the active router without taking down the Multilink interface first. The MWR 1900 routing software keeps sending packets into the disconnected interface for the next few seconds until the Multilink interface goes down. Traps are sent and lost. Traps generated after the link is declared down are kept in the SNMP queue waiting for the routing to become restored.
Workaround: There is currently no workaround.
•
Description: If a virtual access interface is created and that interface is assigned to a multilink group interface by the application of the ppp multilink group group-number interface configuration command, then when the interface goes down, the configuration is not properly removed when the virtual access interface is recycled for reuse.
Perhaps the most visible effect of this symptom, is that if the virtual access interface negotiates to use multilink during a future session (a different use of the virtual access interface than the one when the interface was first created), the interface does not join the designated multilink group interface. Instead, a separate virtual access interface is created for the bundle. This behavior may lead to additional problems since the multilink bundle interface that is created probably does not have the desired configuration that is required for the connection.
This symptom is observed on all Cisco platforms that are running Cisco IOS Release 12.2(5) and later.
Workaround: There is currently no workaround.
•
Description: A router may reload with a bus error when the Point-to-Point protocol (PPP) sessions are disconnected.
This symptom is observed on a Cisco router that is running an interim release of Cisco IOS Release 12.3(4). The symptom occurs on PPP sessions that are not directly associated with an interface or a subinterface (for example, PPP over ATM [PPPoATM] or Layer 2 Tunneling Protocol [L2TP]). Earlier releases of Cisco IOS software do not display this symptom.
Workaround: There is currently no workaround.
•
Description: A Cisco 7200 router may unexpectedly reload. This problem occurs when the router attempts to correct a single bit error in memory (DRAM parity). The symptoms are similar to CSCdu00306 however CSCdu00306 may not correct every situation where this may occur.
This symptom is specific to Network Processing Engine (NPE-400).
Workaround: There is currently no workaround.
•
Description: A vulnerability in the Transmission Control Protocol (TCP) specification (RFC793) has been discovered by an external researcher. The successful exploitation enables an adversary to reset any established TCP connection in a much shorter time than was previously discussed publicly. Depending on the application, the connection may get automatically re-established. In other cases, a user will have to repeat the action (for example, open a new Telnet or Secure Shell [SSH] session). Depending upon the attacked protocol, a successful attack may have additional consequences beyond terminated connection which must be considered. This attack vector is only applicable to the sessions which are terminating on a device (such as a router, switch, or computer) and not to the sessions that are only passing through the device (for example, transit traffic that is being routed by a router). In addition, this attack vector does not directly compromise data integrity or confidentiality.
All Cisco products which contain TCP stack are susceptible to this vulnerability.
More details can be found in the security advisory which is posted at:
http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-ios.shtml
It describes this vulnerability as it applies to Cisco products that run Cisco IOS software.
A companion advisory that describes this vulnerability for products that do not run Cisco IOS software is available at
http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-nonios.shtml
•
Description: Cisco Internetwork Operating System (IOS) Software is vulnerable to a Denial of Service (DoS) attack from crafted IPv6 packets when the device has been configured to process IPv6 traffic. This vulnerability requires multiple crafted packets to be sent to the device which may result in a reload upon successful exploitation.
More details can be found in the security advisory which is posted at:
http://www.cisco.com/warp/public/707/cisco-sa-20050126-ipv6.shtml
•
Description: A document that describes how the Internet Control Message Protocol (ICMP) could be used to perform a number of Denial of Service (DoS) attacks against the Transmission Control Protocol (TCP) has been made publicly available. This document has been published through the Internet Engineering Task Force (IETF) Internet Draft process, and is entitled "ICMP Attacks Against TCP" (draft-gont-tcpm-icmp-attacks-03.txt).
These attacks, which only affect sessions terminating or originating on a device itself, can be of three types:
a.
b.
c.
Successful attacks may cause connection resets or reduction of throughput in existing connections, depending on the attack type.
Multiple Cisco products are affected by the attacks described in this Internet draft.
Cisco has made free software available to address these vulnerabilities. In some cases there are workarounds available to mitigate the effects of the vulnerability.
More details can be found in the security advisory which is posted at:
http://www.cisco.com/warp/public/707/cisco-sa-20050412-icmp.shtml
The disclosure of these vulnerabilities is being coordinated by the National Infrastructure Security Coordination Centre (NISCC), based in the United Kingdom. NISCC is working with multiple vendors whose products are potentially affected.
More details can be found in the security advisory which is posted at:
http://www.cpni.gov.uk/Products/advisories.aspx
•
Description: A Hot Standby Routing Protocol (HSRP) tracking configuration is not accepted when you re-enter the configuration after you first delete it.
This symptom is observed on a Cisco router that runs Cisco IOS Release 12.2S or Release 12.3T.
Workaround: Configure interface tracking by entering the track 100 interface e2/3 line-protocol command. Then, set the HSRP group to track the tracking object number by entering the standby 1 track 100 command.
•
Description: A specifically crafted Transmission Control Protocol (TCP) connection to a telnet or reverse telnet port of a Cisco device running Internetwork Operating System (IOS) may block further telnet, reverse telnet, Remote Shell (RSH), Secure Shell (SSH), and in some cases Hypertext Transport Protocol (HTTP) access to the Cisco device. Telnet, reverse telnet, RSH and SSH sessions established prior to exploitation are not affected.
All other device services will operate normally.
User initiated specially crafted TCP connection to a telnet or reverse telnet port results in blocking further telnet sessions. Whereas, services such as packet forwarding, routing protocols and all other communication to and through the device remains unaffected.
More details can be found in the security advisory which is posted at:
http://www.cisco.com/warp/public/707/cisco-sa-20040827-telnet.shtml
•
Description: Reception of certain IPv6 fragments with carefully crafted illegal contents may cause a router running Cisco IOS to reload if it has IPv6 configured. This applies to all versions of Cisco IOS that include support for IPv6.
The system may be protected by installing appropriate access lists to filter all IPv6 fragments destined for the system. For example:
interface Ethernet0/0ipv6 traffic-filter nofragments in!ipv6 access-list nofragmentsdeny ipv6 any <my address1> undetermined-transportdeny ipv6 any <my address2> fragmentspermit ipv6 any anyThis must be applied across all interfaces, and must be applied to all IPv6 addresses which the system recognizes as its own.
This will effectively disable reassembly of all IPv6 fragments. Some networks may rely on IPv6 fragmentation, so careful consideration should be given before applying this workaround.We would recommend for customers to upgrade to the fixed IOS release. All IOS releases listed in IPv6 Routing Header Vulnerability Advisory at
http://www.cisco.com/warp/public/707/cisco-sa-20070124-IOS-IPv6.shtml contain fixes for this issue.
•
Description: Cisco Internetwork Operating System (IOS) Software is vulnerable to a Denial of Service (DoS) attack and potentially an arbitrary code execution attack from a specifically crafted IPv6 packet. The packet must be sent from a local network segment. Only devices that have been explicitly configured to process IPv6 traffic are affected. Upon successful exploitation, the device may reload or be open to further exploitation.
Cisco has made free software available to address this vulnerability for all affected customers.
More details can be found in the security advisory which is posted at:
http://www.cisco.com/warp/public/707/cisco-sa-20050729-ipv6.shtml
•
Description: In an active router, the relays are closed and the revertive interface should be in the ADMINDOWN state. However, when the interface is brought up, the command standby use-interface loopback 102 revertive is re-issued. This is causing an issue with Hot Standby Routing Protocol (HSRP) as the difference of HSRP priorities between the active and standby routers is no longer 5 but 10. As a result, a router swap will not occur when a single interface goes down.
This situation occurs when re-configuring the redundancy command which brings up revertive int lo102.
Workaround: Manually shut the interface down if it is re-configured.
•
Description: When the no shutdown command is configured on a Multilink interface, some links that are members of the multilink bundle may fail to renegotiate the PPP Link Control Protocol (LCP) and thus fail to activate the bundle.
This symptom occurs very rarely, and is usually associated with several multilink member links and the use of the shutdown and no shutdown commands in rapid succession on the Multilink interface.
Workaround: Configure shutdown on the Multilink interface, wait a few moments, then configure no shutdown.
•
Description: A router may reset its Border Gateway Protocol (BGP) session.
This symptom is observed when a Cisco router that peers with other routers receives an Autonomous System (AS) path with a length that is equal to or greater than 255.
Workaround: Configure the bgp maxas limit command in such a way that the maximum length of the AS path is a value below 255. When the router receives an update with an excessive AS path value, the prefix is rejected and the event is recorded in the log.
•
Description: When an FE cable is pulled out of a Cisco MWR 1900 Mobile Wireless Edge Router, a LINK DOWN Trap is generated. When the cable is inserted back in, the LINK DOWN Trap is generated again, instead of the LINK UP Trap.
This symptom occurs when the FE cable is pulled out and re-inserted in the Cisco MWR 1900 Mobile Wireless Edge Router.
Workaround: There is currently no workaround.
•
Description: The MWR controllers are down when the `detect v54 channel-group' is configured.
This symptom occurs when you Boot both redundancy MWRs at the same time. Some of the controllers can go down in the active MWR.
Workaround: Reload the active MWR to cause a failover. All the controllers will come up after the standby router becomes the active router.
•
Description: Cisco IOS may permit arbitrary code execution after exploitation of a heap-based buffer overflow vulnerability. Cisco has included additional integrity checks in its software, as further described below, that are intended to reduce the likelihood of arbitrary code execution.
Cisco has made free software available that includes the additional integrity checks for affected customers.
This advisory is posted at:
http://www.cisco.com/warp/public/707/cisco-sa-20051102-timers.shtml
•
Description: Through normal software maintenance processes, Cisco is removing deprecated functionality from the OS boot routine. These changes have no impact on system operation or feature availability.
•
Description: Array indexing on toaster address queue may go out of array boundary. This may cause a crash or exhibit unexpected behavior.
Workaround: There is currently no workaround.
•
Description: When you send traffic through a link, after a few seconds the packets of traffic that are sent through the link are not incrementing, even though the Chars Out display clearly shows the packets are incrementing.
Workaround: There is currently no workaround.
Caveats in Cisco IOS Release 12.2(15)MC2b
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)MC2b. 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)MC2b. 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 DVD.
Note
Open Caveats
There are no known open caveats in Cisco IOS Release 12.2(15)MC2b.
Resolved Caveats
This section lists the caveats that are resolved in Release 12.2(15)MC2b.
•
Description: An adjacent T1 link keeps having CRC input errors if the peer router has its T1 link shut. The serial interface on the router in question would keep resetting.
This problem only occurs on the GT96K serial interface when the peer router has its adjacent T1 link shut. This problem is observed in Cisco IOS 12.2T and 12.3.
Workaround: Shut down the T1 link on the router in question.
•
Description: Cisco routers running Cisco IOS supporting Multi Protocol Label Switching (MPLS) are vulnerable to a Denial of Service (DoS) attacks on the MPLS disabled interfaces.
This vulnerability is only present in Cisco IOS release trains based on 12.1T, 12.2, 12.2T, 12.3 and 12.3T. Releases based on 12.1 mainline, 12.1E and all releases prior to 12.1 are not vulnerable.
This bug is a complementary fix to CSCeb56909 which addresses this vulnerability.
More details can be found in the security advisory which is posted at:
http://www.cisco.com/warp/public/707/cisco-sa-20050126-les.shtml
•
Description: When a standby router is reloaded, it takes over as the active router.
This occurs more often when the IP address of the standby router is higher than the active router. Pre-emption occurs on reload.
Workaround: Unconfigure pre-emption when reloading the standby router if this additional swap over is considered an inconvenience and the outage is not considered acceptable.
•
Description: NetFlow Feature Acceleration CLI.
NetFlow Feature Acceleration has been deprecated and removed from Cisco IOS. The global command ip flow-cache feature-accelerate will no longer be recognized in any IOS configuration.
If your router configuration does not currently contain the command ip flow-cache feature-accelerate, this change does not affect you.
This removal does not require an upgrade of your existing installation.
The removal of NetFlow Feature Acceleration does not affect any other aspects of Netflow operation, for example Access-list processing. The features are separate and distinct.
Cisco Express Forwarding (CEF) supersedes the deprecated NetFlow Feature Acceleration.
Additionally, the following MIB objects and OIDs have been deprecated and removed from the netflow mib (CISCO-NETFLOW-MIB):
cnfFeatureAcceleration 1.3.6.1.4.1.9.9.99999.1.3
cnfFeatureAccelerationEnable 1.3.6.1.4.1.9.9.99999.1.3.1
cnfFeatureAvailableSlot 1.3.6.1.4.1.9.9.99999.1.3.2
cnfFeatureActiveSlot 1.3.6.1.4.1.9.9.99999.1.3.3
cnfFeatureTable 1.3.6.1.4.1.9.9.99999.1.3.4
cnfFeatureEntry 1.3.6.1.4.1.9.9.99999.1.3.4.1
cnfFeatureType 1.3.6.1.4.1.9.9.99999.1.3.4.1.1
cnfFeatureSlot 1.3.6.1.4.1.9.9.99999.1.3.4.1.2
cnfFeatureActive 1.3.6.1.4.1.9.9.99999.1.3.4.1.3
cnfFeatureAttaches 1.3.6.1.4.1.9.9.99999.1.3.4.1.4
cnfFeatureDetaches 1.3.6.1.4.1.9.9.99999.1.3.4.1.5
cnfFeatureConfigChanges 1.3.6.1.4.1.9.9.99999.1.3.4.1.6
Caveats in Cisco IOS Release 12.2(15)MC2a
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)MC2a. 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)MC2a. 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 DVD.
Note
Open Caveats
The caveats listed in this section are open in Cisco IOS Release 12.2(15)MC2a.
•
Description: 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.
•
Description: 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.
•
Description: When shutting down a multilink interface, the virtual access (VA) interface associated with the multilink interface flaps.
Workaround: Shut down the subinterface associated with the multilink group.
Resolved Caveats
This section lists the caveats that are resolved in Release 12.2(15)MC2a.
•
Description: Memory allocation failure (MALLOCFAIL) messages no longer occur for Cisco Discovery Protocol (CDP) processes.
•
A Cisco device running Internetwork Operating System (IOS) and enabled for the Open Shortest Path First (OSPF) Protocol is vulnerable to a Denial of Service (DoS) attack from a malformed OSPF packet. The OSPF protocol is not enabled by default.
The vulnerability is only present in IOS release trains based on 12.0S, 12.2, and 12.3. Releases based on 12.0, 12.1 mainlines and all IOS images prior to 12.0 are not affected. Refer to the Security Advisory for a complete list of affected release trains.
Further details and the workarounds to mitigate the effects are explained in the Security Advisory which is available at the following URL:
http://www.cisco.com/warp/public/707/cisco-sa-20040818-ospf.shtml.
•
Description: A Cisco device reloads on receipt of a corrupt CDP packet.
•
Description: The carrier delay detects interface flaps and closes a serial interface even though the carrier delay timer was not exceeded.
•
Description: On occasion, when an MWR 1941-DC router relay closes, syslog messages report the relay as opening.
•
Description: When a PPP multiplexed ICMP echo request is sent to an MWR 1900 series router, the MWR 1941-DC router corrupts the ICMP data payload when de-multiplexing the ICMP packets.
•
Description: Problems with the CDP protocol have been resolved.
•
Description: A Cisco device experiences a memory leak in the CDP process. The device sending CDP packets sends a hostname that is 256 or more characters. There are no problems with a hostname of 255 or fewer characters.
Unreproducible Caveat
The caveat listed in this section has not been reproduced during testing. In the unlikely event you experience the problem described in this section, contact Cisco customer service.
•
Description: Periods of sustained mixed traffic (UDP multicast, IP, and TCP) might cause the MWR 1941-DC router to crash.
Troubleshooting
Collecting Data for Router Issues
To collect data for reporting router issues, issue the following command:
•
Collecting Data for Redundancy Issues
To collect data for redundancy-related issues, issue the following commands while in EXEC mode:
•
•
•
•
•
•
Collecting Data for ROMmon Issues
To collect data for ROMmon issues, issue the following command while in EXEC mode:
•
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
Note
Router(config-controller)# channel-group 0 timeslots 1-24 speed 64Step 5
Router(config-controller)# cablelength feet
Note
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:
•
–
–
–
–
•
•
On Cisco.com at:
Technical Support and Documentation: Routers: Cisco MWR 1900 Mobile Wireless Routers:
On the Documentation DVD at:
Routers: Cisco MWR 1900 Mobile Wireless Routers:
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 Documentation: Cisco IOS Software: Cisco IOS Release 12.2: New Feature Documentation:12.2-Based New Features: New Features in Release 12.2 MC
Obtaining Documentation
Cisco documentation and additional literature are available on Cisco.com. Cisco also provides several ways to obtain technical assistance and other technical resources. These sections explain how to obtain technical information from Cisco Systems.
Cisco.com
You can access the most current Cisco documentation at this URL:
http://www.cisco.com/univercd/home/home.htm
You can access the Cisco website at this URL:
You can access international Cisco websites at this URL:
http://www.cisco.com/public/countries_languages.shtml
Documentation DVD
Cisco documentation and additional literature are available in a Documentation DVD package, which may have shipped with your product. The Documentation DVD is updated regularly and may be more current than printed documentation. The Documentation DVD package is available as a single unit.
Registered Cisco.com users (Cisco direct customers) can order a Cisco Documentation DVD (product number DOC-DOCDVD=) from the Ordering tool or Cisco Marketplace.
Cisco Ordering tool:
http://www.cisco.com/en/US/partner/ordering/
Cisco Marketplace:
http://www.cisco.com/go/marketplace/
Ordering Documentation
You can find instructions for ordering documentation at this URL:
http://www.cisco.com/univercd/cc/td/doc/es_inpck/pdi.htm
You can order Cisco documentation in these ways:
•
http://www.cisco.com/en/US/partner/ordering/
•
Documentation Feedback
You can send comments about technical documentation to bug-doc@cisco.com.
You can submit comments by using the response card (if present) behind the front cover of your document or by writing to the following address:
Cisco Systems
Attn: Customer Document Ordering
170 West Tasman Drive
San Jose, CA 95134-9883We appreciate your comments.
Cisco Product Security Overview
Cisco provides a free online Security Vulnerability Policy portal at this URL:
http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html
From this site, you can perform these tasks:
•
•
•
A current list of security advisories and notices for Cisco products is available at this URL:
If you prefer to see advisories and notices as they are updated in real time, you can access a Product Security Incident Response Team Really Simple Syndication (PSIRT RSS) feed from this URL:
http://www.cisco.com/en/US/products/products_psirt_rss_feed.html
Reporting Security Problems in Cisco Products
Cisco is committed to delivering secure products. We test our products internally before we release them, and we strive to correct all vulnerabilities quickly. If you think that you might have identified a vulnerability in a Cisco product, contact PSIRT:
•
•
Tip
Never use a revoked or an expired encryption key. The correct public key to use in your correspondence with PSIRT is the one that has the most recent creation date in this public key server list:
http://pgp.mit.edu:11371/pks/lookup?search=psirt%40cisco.com&op=index&exact=on
In an emergency, you can also reach PSIRT by telephone:
•
•
Obtaining Technical Assistance
For all customers, partners, resellers, and distributors who hold valid Cisco service contracts, Cisco Technical Support provides 24-hour-a-day, award-winning technical assistance. The Cisco Technical Support Website on Cisco.com features extensive online support resources. In addition, Cisco Technical Assistance Center (TAC) engineers provide telephone support. If you do not hold a valid Cisco service contract, contact your reseller.
Cisco Technical Support Website
The Cisco Technical Support Website provides online documents and tools for troubleshooting and resolving technical issues with Cisco products and technologies. The website is available 24 hours a day, 365 days a year, at this URL:
http://www.cisco.com/techsupport
Access to all tools on the Cisco Technical Support Website requires a Cisco.com user ID and password. If you have a valid service contract but do not have a user ID or password, you can register at this URL:
http://tools.cisco.com/RPF/register/register.do
Note
Submitting a Service Request
Using the online TAC Service Request Tool is the fastest way to open S3 and S4 service requests. (S3 and S4 service requests are those in which your network is minimally impaired or for which you require product information.) After you describe your situation, the TAC Service Request Tool provides recommended solutions. If your issue is not resolved using the recommended resources, your service request is assigned to a Cisco TAC engineer. The TAC Service Request Tool is located at this URL:
http://www.cisco.com/techsupport/servicerequest
For S1 or S2 service requests or if you do not have Internet access, contact the Cisco TAC by telephone. (S1 or S2 service requests are those in which your production network is down or severely degraded.) Cisco TAC engineers are assigned immediately to S1 and S2 service requests to help keep your business operations running smoothly.
To open a service request by telephone, use one of the following numbers:
Asia-Pacific: +61 2 8446 7411 (Australia: 1 800 805 227)
EMEA: +32 2 704 55 55
USA: 1 800 553-2447For a complete list of Cisco TAC contacts, go to this URL:
http://www.cisco.com/techsupport/contacts
Definitions of Service Request Severity
To ensure that all service requests are reported in a standard format, Cisco has established severity definitions.
Severity 1 (S1)—Your network is "down," or there is a critical impact to your business operations. You and Cisco will commit all necessary resources around the clock to resolve the situation.
Severity 2 (S2)—Operation of an existing network is severely degraded, or significant aspects of your business operation are negatively affected by inadequate performance of Cisco products. You and Cisco will commit full-time resources during normal business hours to resolve the situation.
Severity 3 (S3)—Operational performance of your network is impaired, but most business operations remain functional. You and Cisco will commit resources during normal business hours to restore service to satisfactory levels.
Severity 4 (S4)—You require information or assistance with Cisco product capabilities, installation, or configuration. There is little or no effect on your business operations.
Obtaining Additional Publications and Information
Information about Cisco products, technologies, and network solutions is available from various online and printed sources.
•
http://www.cisco.com/go/marketplace/
•
•
•
http://www.cisco.com/go/iqmagazine
•
•
http://www.cisco.com/en/US/learning/index.htm
Feedback