Cisco IOS Release 15.2(1)GC1 Release Notes

Table Of Contents

Release Notes for Cisco IOS Release 15.2(1)GC

Contents

Image Information and Supported Platforms

Related Documentation

New and Changed Information

New Hardware Features

New Software Features

Limitations

Troubleshooting

Recommended Configuration Settings

Caveats

Open Caveats for the Cisco 5915 ESR Running Cisco IOS Release 15.2(1)GC

Obtaining Documentation, Obtaining Support, and Security Guidelines

Release Notes for Cisco IOS Release 15.2(1)GC

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Current Release:
15.2(1)GC - August 12, 2011

The following release notes support Cisco IOS Release 15.2(1)GC. They are updated to describe new features, limitations, troubleshooting, recommended configurations, caveats, and how to obtain support and documentation.

Contents

This publication consists of the following sections:

•Image Information and Supported Platforms

•Related Documentation

•New and Changed Information

•Limitations

•Troubleshooting

•Recommended Configuration Settings

•Caveats

•Obtaining Documentation, Obtaining Support, and Security Guidelines

Image Information and Supported Platforms

These images are bug compatible with Cisco IOS release 15.2(1)T.

Cisco IOS Release 15.2(1)GC includes the following Cisco IOS images:

•c2900-universalk9-mz.SPA

•c2951-universalk9-mz.SPA

•c3900-universalk9-mz.SPA

•c3900e-universalk9-mz.SPA

•c5915--adventerprisek9-mz.SPA

•c5915-entbase-mz.SPA

•c5940-adventerprisek9-mz.SPA

•c5940-entbase-mz.SPA

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Note You must have a Cisco.com account to download the software.

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Cisco IOS Release 15.2(1)GC is supported on the following platforms:

•Cisco 2901 Integrated Services Router

•Cisco 2911 Integrated Services Router

•Cisco 2921 Integrated Services Router

•Cisco 2951 Integrated Services Router

•Cisco 3925 Integrated Services Router

•Cisco 3945 Integrated Services Router

•Cisco 3945e Integrated Services Router

•Cisco 5915 Embedded Services Router

•Cisco 5940 Embedded Services Router

Related Documentation

The following documentation is available for use:

•Software Configuration Guide, Cisco IOS Release 15.2(1)GC (OL-24065-01)

•Mobile Ad Hoc Networks for Router-to-Radio Communications (OL-19437-02)

•Software documentation for Cisco IOS Release 15.2(1)T

New and Changed Information

This section contains the following information

•New Hardware Features

•New Software Features

New Hardware Features

The following new hardware is supported in 15.2(1)GC:

•Cisco 5915 Embedded Services Router

For detailed information, refer to the following document:

Cisco 5915 Embedded Services Router Hardware Technical Guide (OL-23839-01)

New Software Features

Cisco IOS Release 15.2(1)GC is based on Cisco IOS Release 15.2(1) T. Refer to the following URL for information on the new software features added to Release 15.2T: http://www.cisco.com/en/US/docs/ios/15_2m_and_t/release/notes/15_2m_and_t.html

The following new software feature has been added to this release:

•Transmit flow control—You can enable transmit flow control for an interface using the [no] flowcontrol send command

Limitations

The following limitations exist in this release:

•The QoS policy can only be applied to one outgoing interface the PPPoE session is traversing.

A QoS output policy can be applied to the Virtual Template or the VMI, but not at the same time. If a policy is attached, the outgoing physical interfaces (i.e. physical-interface FastEthernet0/0) should not have output policy applied. It is recommended that the policy be attached to the Virtual Template. The other option is to apply the policy to the VMI but not to the Virtual Template or Ethernet interface.

•When a service policy is applied to the VMI and packets are dropped on the VA due to credit starvation, the show policy-map int VMI command will not show these dropped packets. There is no back pressure between the interfaces in this configuration. The VMI does not know that packets were dropped by the VA or the Ethernet physical interfaces.

•RFC 5578 credits do not tie into QoS formulas. Credits only indicate to QoS the ability to transmit a packet or not. If there are enough credits a packet will be transmitted from the highest priority queue. When there are not enough credits, packets will be queued.

•QoS policy may drop on an interface when the interface receives an invalid CDR value.

•To prevent dropping QoS policy, the current data rate (CDR) is range checked to a floor value of 10kbps and a ceiling value of the physical interface speed. If CDR is below the floor value, the QoS rate shaping is set to the floor value. If CDR is above the ceiling value, the QoS rate shaping is set to the ceiling value. The floor value is 10kbps. The ceiling value is limited to the physical interface speed.

•In addition to defining floor and ceiling bandwidth values, the class bandwidth percentage must also be 10% or greater. If the class bandwidth is configured to a value less than 10% and the CDR value is less than 10kbps, the QoS policy will be removed. (CSCth43582)

•Software Release 15.2(1)GC may have OSPFv3 incompatibility issues with software versions 12.4(22)GC1 or older. To avoid any issues, ensure that all routers run the same version of Cisco IOS.

The following limitation exists for the Cisco 5915 ESR:

•The VLAN database is maintained in the Flash as a file (vlan.dat). This file is created or updated only while adding, deleting, or modifying a VLAN to a switchport. Do not delete the vlan.dat file.

Copying a configuration, with switch ports configured with VLANs, through TFTP to the Cisco 5915 ESR running configuration, the vlan.dat file may not be created automatically in flash. As a result, the VLANs configured in the switch ports do not exist, even though the running config shows the switch ports configured with VLANs. If a VLAN is appears as 'Line protocol down' the VLAN association needs to be updated by configuring the VLAN database explicitly by entering the vlan vlan_number command.

When you copy any configuration file with VLAN configurations to TFTP serer, back up the corresponding vlan.dat file to TFTP. And when you copy a configuration file from a TFTP server to the Cisco 5915 ESR, copy the corresponding vlan.dat file to C5915 router flash. (CSCtq04969)

•When you copy files to the FLASH, the copy process may become very slow when FLASH has limited free space. Delete unused files to free up space, If issue persists, enter the format flash command to reclaim space from deleted files. (CSCtl42754)

•The Output drops counter may not be accurate under stress. You can verify the number of output drops in output for the show controller command. (CSCtl70552)

Troubleshooting

Use the following command to collect data when reporting router issues:

•show tech

Use the following command to collect data to confirm neighbor establishment:

•show vmi neighbor

Use the following command to display active PPPoE sessions:

•show pppoe session

Use the following command to examine QoS issues:

•show policy-map interface virtual-access interface-number

Use the following commands to debug vmi issues:

•debug vmi error

•debug vmi pppoe

Use the following commands to verify PPPoE and VMI interface operation related to credit information:

•show vmi neighbor detail

•show pppoe session all

Use the following command to debug PPPoE issues:

•debug pppoe error

Use the following command to display OSPFv3 traffic data including LSA counts:

•show ospfv3 traffic

Use the following command to display EIGRP traffic data:

•show ip eigrp traffic [as-number]

The following command is not supported, but may be useful in debugging EIGRP MANET metric issues:

•debug eigrp neighbor

Use the following command to collect data when reporting ROMMON issues:

•showmon

Complete the following procedure to collect data if a router reboot to rommon occurs:

1. dir flash: - Use to locate the Route Processor (crashinfo*) or Network Processor (pxf_crashinfo*) exception file.

2. E-mail the exception file with a write up to the Cisco Beta support email address.

Recommended Configuration Settings

Use the following configuration guidelines when enabling class-based weighted fair-queuing:

•Enter the following command to turn off creation of virtual-template subinterfaces:

no virtual-template subinterface

•Enter the following commands to create a policy map with class-based weighted fair-queuing and apply the newly created policy-map to the virtual template:

class-map match-any chat

 match  dscp af11

class-map match-any voice

 match  dscp ef 

policy-map mypolicy

 class chat

  bandwidth percent 40

 class voice

  bandwidth percent 40

interface virtual-template number

service-policy output mypolicy

•No additional configuration is supported on the policy-map.

Use the following configuration guidelines when disabling PPP keepalives:

•You can turn off the PPP keepalive messages to decrease overhead when the radio alerts the router with a PADT message that the layer-2 RF connection is no longer available. Turning off the PPP keepalive messages may also avoid the potential for the router to terminate the connection based on missed PPP keepalives over a poor RF link.

•To turn off the PPP keepalive messagess, enter the following command for the virtual-template.

interface virtual-template number

no keepalive

Use the following configuration guidelines for setting the recommended OSPF values of radio link metrics:

•You may have to dampen the amount of changes in order to reduce network-wide churn because cost components may change rapidly.

•The following recommended values are intended as a starting point for optimizing a OSPFv3 network and are based on network simulations that may reduce the rate of network changes. Each network may have unique characteristics that require different settings to optimize actual network performance.

You must configure these values for both OSPFv3 IPv4 and IPv6

S1 = ipv6 ospf dynamic weight throughout
     Recommended value = 0
     Default=100
S2 = ipv6 ospf dynamic weight resources
     Recommended value = 29
     Default = 100
S3 = ipv6 ospf dynamic weight latency
     Recommended value = 29
     Default = 100
S4 = ipv6 ospf dynamic weight L2 factor
     Recommended value = 29
     Default = 100

The following is an example configuration for a VMI interface or on the virtual template when running bypass mode:

interface vmi1

...

ipv6 ospf cost dynamic weight throughput 0

ipv6 ospf cost dynamic weight resources 29

ipv6 ospf cost dynamic weight latency 29

ipv6 ospf cost dynamic weight L2-factor 29

...

ospfv3 instance 64 cost dynamic weight throughput 0

ospfv3 instance 64 cost dynamic weight resources 29

ospfv3 instance 64 cost dynamic weight latency 29

ospfv3 instance 64 cost dynamic weight L2-factor 29

For more information on OSPF commands, refer to the following URL: http://www.cisco.com/en/US/docs/ios/iproute/command/reference/irp_book.html

Use the following configuration guidelines for disabling split horizon in EIGRP:

•By default split horizon is enabled in EIGRP. You can disable split horizon by entering the no ip split-horizon eigrp command for the respective autonomous system number.

interface vmi number

no ip split-horizon eigrp as-number

•Enter the following command to disable the ip redirects on the vmi interface when you are configuring the vmi interface for EIGRP.

interface vmi number

no ip redirects

Use the following configuration guidelines for setting EIGRP values of radio link metrics:

•EIGRP monitors the following metrics on an interface allowing the tuning of the EIGRP metric calculations; use the metric weights router configuration command:

metric weights tos k1 k2 k3 k4 k5

where tos denotes type of service (currently, it must always be zero) and use the following default values for weights:

k1 - 1

k2 - 0

k3 - 1

k4 - 0

k5 - 0

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Note The no metric weights command restores the K-values to the above listed defaults:

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•Most configurations use the Delay and Bandwidth metrics with Bandwidth taking precedence.

•You must set the weights identically on all routers in an autonomous system.

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Note If you wish to use the default k-values you do not need to enter the metric weights command.

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•To set the metric dampening value for EIGRP, enter the following commands for either change-based or interval-based dampening of metric updates received through VMI:

– Change Based Dampening:

ip50-1(config)#int vmi 4

  ip50-1(config-if)#eigrp 100 interface dampening-change 40

Default Value for Change Based Dampening: 50%

To enable change-based dampening using the default Value, enter the following command:

eigrp 100 interface dampening-change

To disable change-based dampening, enter the following command:

no eigrp 100 interface dampening-change

– Interval-based Dampening:

ip50-1(config)#int vmi 4

ip50-1(config-if)#eigrp 100 interface dampening-interval 20

Default Timer value for Interval-based Dampening: 30 seconds

To enable interval-based dampening using the default Value, enter the following command:

eigrp 100 interface dampening-interval

To disable interval-based dampening, enter the following command:

no eigrp 100 interface dampening-interval

•The following exceptions will result in an immediate update:

–a down interface

–a down route

–any change in a metric triggered outside the scope of the VMI metric update.

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Note No recommended values other than default are currently available.

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For more information on EIGRP commands, refer to the following URL: http://www.cisco.com/en/US/docs/ios/iproute/command/reference/irp_book.html

Caveats

Caveats describe unexpected behavior in Cisco IOS releases. Caveats listed as open in a prior release are carried forward to the next release as either open or resolved.

This section lists caveats in the Cisco IOS Release 15.2(1)GC images:

Open Caveats for the Cisco 5915 ESR Running Cisco IOS Release 15.2(1)GC

This section lists open caveats for the Cisco 5915 ESR running Cisco Release IOS 15.2(1)GC:

•CSCtr42899

The Cisco 5915 ESR may reboot while running stress test with 64 byte frame size at high rate.

Workaround: There is no workaround.

•CSCtq80319

The No sreloc section system message displays while booting the system. This does not affect the bootup.

Workaround: There is no workaround.

•CSCtn27966

When Password-recovery is set to 0x1 and 0x2002 on the Cisco 5915 ESR, password recovery may become disabled.

Workaround: There is no workaround.

•CSCts04767

•Flow control is enabled on switch ports. Currently there is no method to disable flow control.

Workaround: There is no workaround.

Obtaining Documentation, Obtaining Support, and Security Guidelines

For information on obtaining documentation, submitting a service request, and gathering additional information, see the monthly What's New in Cisco Product Documentation, which also lists all new and revised Cisco technical documentation, at the following URL:

http://www.cisco.com/en/US/docs/general/whatsnew/whatsnew.html

Subscribe to the What's New in Cisco Product Documentation as a Really Simple Syndication (RSS) feed and set content to be delivered directly to your desktop using a reader application. The RSS feeds are a free service. Cisco currently supports RSS Version 2.0.

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