Cisco IOS Release 12.0(25)SX7

These release notes provide information about Cisco IOS software Release 12.0(25)SX7 for the Cisco 10000 series router. 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.

Cisco IOS Release 12.0(25)SX7 is based on Cisco IOS Release 12.0(25)S. The Cisco 10000 router supports a subset of the new features in Cisco IOS Release 12.0(25)S. For more information, see the "New Features—Cisco IOS Release 12.0(25)S" section. This section lists the features supported on the Cisco 10000 router.

To view the release notes for the following Cisco IOS software releases, go to the following URLs:

System Requirements

This release requires that you have the performance routing engine (PRE), part number ESR-PRE1 installed in the Cisco 10000 router chassis. To verify which PRE is installed in the router, use the show version command.

Memory Requirements

The following table lists memory requirements for the Cisco 10000 series router:


Feature Set by Router	Image Name	Flash Memory	DRAM Memory	Runs From
Router	c10k-p10-mz	40 MB	512 MB	RAM
Service Provider/ Secured Shell 3DES	c10k-k4p10-mz	40 MB	512 MB	RAM

Upgrading to a New Software Release

Upgrading from Earlier Cisco IOS Releases

Upgrading from Cisco IOS Release 12.0(14)SL or from Earlier Releases Based on Cisco IOS Release 12.0(x)SL

If you are upgrading your software from Cisco IOS Release 12.0(14)SL or from earlier releases based on Cisco IOS Release 12.0(x)SL to Cisco IOS Release 12.0(25)SX7, save your current configuration file. If you decide to reinstall Cisco IOS Release 12.0(14)SL or an earlier release, you must also reinstall the configuration file associated with that release because some Border Gateway Protocol (BGP) configuration file entries in Cisco IOS Release 12.0(25)SX7 are not compatible with Cisco IOS Release 12.0(14)SL or earlier releases.

Upgrading Software on Redundant PREs

The procedure included in the "Upgrading Software on Redundant PREs" section instructs you to tell the Cisco 10000 series router the location in which the new boot image resides. Be sure to specify c10k-p10-mz instead of the c10k-p6-mz image name indicated in the documentation.

New Features—Cisco IOS Release 12.0(25)SX7

Cisco IOS Release 12.0(25)SX7 contains no new features, but includes all of the new features and performance enhancements introduced in Cisco IOS Release 12.0(25)SX1 and Cisco IOS Release 12.0(25)SX, which is based on Cisco IOS Release 12.0(25)S.

New Features—Cisco IOS Release 12.0(25)SX1

Cisco IOS Release 12.0(25)SX1 provides the following performance enhancements, but contains no new features.

This release improves the performance of the VTMS Link Utilization feature. The default queue size is based on link bandwidth instead of queue bandwidth as in previous releases.

The QA Error Recovery feature enables the router to recover quickly from problems known as QAERRORs, which can be caused by hardware or software issues. When a QAERROR occurs, the router might stop responding while it tries to recover from the problem. QA error recovery reduces the router down time to as little as one second. Previously, a fully loaded router might be down for up to five minutes (300 seconds).

The QA error recovery feature is enabled by default. To disable the feature, issue the following command:

When QA error recovery is successful, the router displays a console message indicating success. In addition, the show controllers cbus command indicates the number of QAERROR recoveries.

The following sample console messages show an occurrence of a QAERROR and the router's recovery from the error. The router might display additional messages during error recovery (which can help service technicians diagnose the cause of the problem).

The following example shows QA error recovery information in show controllers cbus command output:

New Features—Cisco IOS Release 12.0(25)SX

Cisco IOS Release 12.0(25)SX introduces support on the Cisco 10000 series router for the following features:

The Policy-Map Scaling feature increases the system-wide number of quality of service (QoS) policy maps that you can configure. In Cisco IOS Release 12.0(25)SX, the Cisco 10000 series router supports up to 4,096 policy maps. Each policy-map command counts as one policy map. The policy-map command syntax is unchanged. The maximum number of classes that you can configure in a policy is 32 classes.

The Percent-Based Policing feature enables you to specify the police rate as a percentage of the bandwidth of the network interface on which policing is applied. To specify the police rate as a percentage, use the percent percent option of the police command:

The percent argument is a value from 1 to 100 and is required when you use the percent keyword.

When you use a percent-based police command within a nested policy, the police percent is based on the policy's topmost, class-default, shape rate. Otherwise, the police percent is based on the bandwidth of the network interface on which the police command is applied.

The Random Early Detection (RED) with Queue-Limit feature expands your ability to customize the size of a RED queue. In Cisco IOS Release 12.0(25)SX, you can simultaneously use the queue-limit and random-detect commands in the same class of a policy.

The Enhanced RED Statistics feature maintains RED drop statistics for each IP precedence or differentiated services code point (DSCP) value.

Note In releases earlier than Cisco 12.0(25)SX, RED drop counts were maintained only for each class.

The 3-Level Policies feature increases the hierarchical levels of a nested QoS policy from two to three levels. A 3-level policy is typically used to define the transmission capacity of a virtual circuit in the top level, class-based queuing at the middle level, and marking or metering in the bottom level.

The service-policy command configured inside a policy map is used to define a hierarchical policy. The syntax of the command is unchanged. You can use the service-policy command in the top and middle levels of a 3-level policy.

The Virtual Circuit (VC) Oversubscription feature enables service providers to improve network utilization of otherwise underutilized shared networks by leveraging statistical multiplexing on ATM, Frame Relay, and IEEE 802.1Q networks. Instead of supporting only unconditional reservation of network bandwidth to VCs, the Cisco 10000 Cisco 10000 series router offers VC oversubscription to statistically guarantee bandwidth to VCs.

To configure VC oversubscription for Frame Relay and IEEE 802.1Q, use the service-policy command. You can optionally use the service-policy class configuration command, creating a nested policy to manage traffic within a virtual circuit. For this reason, the term Nested Policy-Map Oversubscription is sometimes used to refer to VC Oversubscription.

To enable oversubscription of ATM VCs, you must configure the following interface configuration command in service-internal mode:

Note You do not need to use the service-policy command to specify the ATM VC oversubscription, because a variable bit rate (VBR) ATM VC uses sustained cell rate (SCR) to define the VC's average transmission rate.

The External Border Gateway Protocol (EBGP) Label Distribution feature enables you to configure a carrier supporting carrier network that uses BGP to distribute routes and MPLS labels between the provider edge (PE) and customer edge (CE) routers of a backbone carrier and a customer carrier. The backbone carrier offers BGP and MPLS VPN services. The customer carrier can be one of the following:

For information on how to use BGP to distribute MPLS labels and routes for both types of customer carrier, refer to the MPLS VPN Carrier Supporting Carrier—IPv4 BGP Label Distribution, Release 12.0(21)ST feature module and the Inter-Autonomous Systems for MPLS VPNs, Release 12.1(5)T feature module.

New Features—Cisco IOS Release 12.0(25)S

The following is a brief list of the new features in Cisco IOS Release 12.0(25)S on which Cisco IOS Release 12.0(25)SX is based. Only new features that are supported by the Cisco 10000 Cisco 10000 series router are listed here. New features for other platforms (such as the Cisco 12000 series router) are not listed.

Introduced on the Cisco 10000 Cisco 10000 series router in Cisco IOS Release 12.0(23)SX, the Link Fragmentation and Interleaving (LFI) feature reduces delay and jitter on slower-speed links by breaking up large datagrams and interleaving low-delay traffic packets (such as voice) with the smaller packets resulting from the fragmented datagram. The feature supports Frame Relay (FRF.12) end-to-end and Multilink PPP (MLPPP).

Introduced on the Cisco 10000 Cisco 10000 series router in Cisco IOS Release 12.0(23)SX, the single rate 3-Color Marker feature meters an IP packet stream and marks its packets different colors, based on the Committed Information Rate (CIR) and two associated burst sizes: Committed Burst Size (CBS) and Excess Burst Size (EBS). This feature is useful, for example, for ingress policing of a service, where service eligibility is determined only by the burst's length, and not its peak rate.

The Multicast for Multiprotocol Label-Switching (MPLS)/Virtual Private Network (VPN) feature enables service providers to offer multicast services over their MPLS core network. This feature was introduced on the Cisco 10000 Cisco 10000 series router in Cisco IOS Release 12.0(23)SX.

This feature enables you to limit the number of routes that can be redistributed into the Open Shortest Path First (OSPF) protocol. The feature helps to eliminate the potential for flooding that might occur when a large number of routes are accidentally redistributed into OSPF.

This feature enables you to limit the number of routes that can be redistributed into the Intermediate System-to-Intermediate System (IS-IS) protocol. This feature helps to eliminate the potential for flooding that might occur when a large number of routes are accidentally redistributed into IS-IS.

This feature enables you to slow down the rate at which the Open Shortest Path First (OSPF) protocol sends Link State Advertisement (LSA) updates during periods of network instability. This feature uses a back-off algorithm to perform the LSA throttling.

Limitations and Restrictions

The following limitations and restrictions apply to the Cisco 10000 series router 3-Level Policies feature:

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A top-level policy must specify only the class named class-default with only the shape command specified before the service-policy command attaches an inner policy.

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In an inner policy, to attach a service-policy command to a class's bottommost policy, do not configure the police and set commands for the class. Classes without a service-policy command configured are not restricted from using the police and set commands.

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In a bottommost policy, configure only the police and set commands for a class.

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Define each bottommost class map to match only those packets that also match its parent class map. For example, the union of the set of packets of a bottommost class and that of its parent class must be equal to the set of packets that match the parent class.

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The nested-policy shape rate is reserved for nested-policy traffic only. Excess bandwidth is not used for other traffic.

Note

The actual shape rate applied to nested-policy traffic might differ from that specified in the policy. For example, a specified shape rate of 10.5 Mbps might be mapped to 11 Mbps. Use the command show policy-map interface to determine the actual shape rate.

Open Caveats—Cisco IOS Release 12.0(25)SX7

Table 1 Open Caveats in Cisco IOS Release 12.0(25)SX7
Caveat	Description
CSCea42432	(Duplicate of CSCea52307) If you delete a service policy from an ATM interface, a traceback message or error message may appear. Workaround: None.
CSCea74742	Policing conformed packets might be less than expected when the normal burst size is set to less than two times the packet size. Workaround: Change the normal burst size to a value larger than 2 times the police frame size.
CSCea93642	When a large number of policy maps are configured on the Cisco 10000 Cisco 10000 series router, it could take more time than expected before all the policy maps activate. Before an interface's policy map activates, the traffic on the interface receives default treatment. The router compiles a super access control list (ACL) for each policy map configured. On an average, the compilation of one super ACL takes approximately one-half second. When a large number of policy maps are configured, the router requires more time to compile all of the super ACLs. Workaround: Wait approximately 0.65 seconds for each policy-map to become operational. For more than one policy map, wait (N * 0.65) seconds for all the policy maps to become operational (where N is the number of policy maps).
CSCeb02953	When traffic is sent through an ATM subinterface to which a QoS service policy is attached, the packet count of the output queue obtained by using the show policy-map interface command does not match the packet output count obtained by using the show interface atm-subinterface command. Workaround: To obtain the correct packet output count, use the show policy-map interface command. Do not use the show interface atm-subinterface command to obtain packet output counts for ATM subinterfaces.
CSCeb27728	When microcode is reloading and traffic is running over the interface, the interface output packet and byte counters display incorrect values. Workaround: Clear the counters.
CSCeb38728	Under extremely rare circumstances, when you remove a 3-level policy map attached to 4,000 VLAN interfaces, the Cisco 10000 series router stops responding. Workaround: None.

Resolved Caveats—Cisco IOS Release 12.0(25)SX7

This section describes caveats that were fixed in Cisco IOS Release 12.0(25)SX7.

For information about caveats fixed in other Cisco IOS releases, refer to the appropriate Release Note document at the following URL:

Previously, when a Multiprotocol Label Switching (MPLS) edge router performed hardware-assisted forwarding, the hardware and software MPLS forwarding tables might be inconsistent. An example of an MPLS edge router is a provider edge (PE) router in an MPLS virtual private network (VPN).

This problem occurred when you executed either of the following command sequences on the MPLS edge router:

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The shutdown command followed by the no shutdown command on one of the outgoing interfaces enabled for MPLS.

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The no mpls ldp command followed by the mpls ldp command on one of the outgoing interfaces enabled for MPLS.

Previously, when you changed the type of service (TOS) on packets encapsulated in a Multiprotocol Label Switching (MPLS) virtual private network (VPN) tunnel, the TOS of the interior (encapsulated) packet did not change appropriately and was classified incorrectly at the de-encapsulating router.

This problem occurred when you applied input policing to an interface, associated a virtual routing and forwarding (VRF) instance with the interface, the interface was receiving multicast traffic from the customer edge (CE) router, and the router was configured for MPLS VPN.

Previously, under a specific configuration using multiple E1 (framed or unframed) interfaces and 1500-byte IP packets, the maximum priority queue (PQ) latency was greater than 2 times the specified maximum transmission unit (MTU) plus 6 milliseconds. The following describes the conditions under which this problem occurred.

Seven queues were configured on each (1984k) E1 interface with the following bandwidths: PQ - 98k, C1 - 256k, C2 - 256k, C3 - 256k, C4 - 256k, CD - 98k, and MGMT - 20k.

The high latency was observed with 20 interfaces configured and bidirectional traffic was being sent at the following (per interface) pps rates to each queue, respectively:

Previously, when you configured class-based weighted fair queuing (CBWFQ) on a Frame Relay permanent virtual circuit (PVC), queues could drop packets even if there was no traffic on other queues on the same link and the input traffic was less than the link bandwidth. This occurred when queue bandwidth was configured as a small percentage of link bandwidth.

Previously, an ACL applied to an ATM subinterface might not function correctly after a PRE switchover. This problem occurred in a Cisco 10008 router that was configured with a PRE2.

Previously, when you configured Multiprotocol Label Switching (MPLS) over Multilink PPP (MLPPP), the parallel express forwarding (PXF) microcode reloaded. After the PXF microcode reloaded, packet forwarding resumed.

Previously, the parallel express forwarding (PXF) processor could drop ATM adaptation layer 5 (AAL5) Connectionless Network Service (CLNS) Intermediate System-to-Intermediate System (IS-IS) packets when the path from the PXF processor to the route processor (RP) was congested. This could occur when the RP was very busy.

Previously, when you deleted an access control list (ACL) used in many route maps, SuperACL process memory usage increased significantly.

Previously, when redundant Performance Routing Engines (PREs) were configured, the write memory command was in progress on the active PRE, an application on the standby PRE accessed standby NVRAM, and then there was a switchover to the standby PRE, an error message appeared similar to:

Previously, when you attached a policy map to a Multilink PPP (MLPPP) interface or when links were added to an MLPPP interface and then the Cisco 10000 series router reloaded, the packet queue size on an MLPPP bundle could be larger than necessary. This could reduce scalability during the configuration of multiple MLPPP interfaces, because the system could run out of resources to allocate the packet queues. There could be substantial traffic congestion, because traffic that should have been dropped due to queue overflow was not dropped.

Previously, when new links were added to a Multilink PPP (MLPPP) interface that already had a policy map with priority class attached, the priority traffic on the MLPPP interface could exceed the configured bandwidth limits. Links could be added as result of a system reload or bootup, the link going up or down, or the user configuring more links on the bundle.

Previously, when network interfaces were operating at or above OC-3 speeds and a policy map class containing the priority percent percentage command was loaded at or greater than the specified rate, other classes were left with less than their fair share of the bandwidth and their bandwidth ratio was adversely affected.

Previously, the router reloaded unexpectedly as ATM VCs came up. This problem occurred when ACLs were applied on ATM interfaces, and only rarely then, on images that contain the fix for CSCed72686.

Previously, the router dropped packets when Unicast Reverse Path Forwarding (URPF) was configured on an interface. This problem occurred when the router had 2 paths (outgoing interfaces) to a destination in the FIB table and URPF was enabled on one of the outgoing interfaces.

Previously, the router stopped forwarding traffic for some load balanced recursive prefixes, such as a BGP route with equal cost IGP paths to the BGP next hop. If any Multiprotocol Label Switching (MPLS) Label Distribution Protocol (LDP) adjacency on the router flapped or the router itself flapped, the hardware loadshare pointers for the recursive prefixes could point to old information because Cisco Express Forwarding (CEF) did not send updates to the Parallel Express Forwarding (PXF) processor with new label information.

Previously, outbound security ACLs were not applied properly on Cisco 10000 Series routers. This problem occurred on all 12.0S images that contain the fix for CSCed72686.

Previously, when you configured redundant Performance Routing Engines (PREs) and saved the configuration first to the standby PRE and then to the active PRE, the configuration might not be saved. Additionally, an error message appeared similar to the following:

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Table Of Contents

Release Notes for the Cisco 10000 Series Router for Cisco IOS Release 12.0(25)SX7

Contents