Table Of Contents
Cisco Express Forwarding Enhancements: Removal of IP Fast Switching and Introduction of CLI Changes
Information About Cisco Express Forwarding Enhancements
Introduction of Cisco Express Forwarding Enhancements
Cisco Express Forwarding Enhancements for Cisco IOS Release 12.4(20)T
Removal of Support for IPv4 Fast Switching
Removed, Obsolete, and No Longer Supported Cisco Express Forwarding Commands
Cisco Express Forwarding CLI Command Output Changes
show ipv6 cef <prefix> internal
show ip cef exact-route <source> <destination> detail
show ip cef exact-route <source> <destination>
show ip cef adjacency <interface> <next-hop>
show ipv6 cef unresolved detail
New Commands for the Cisco Express Forwarding Enhancements Feature
show adjacency link {ipv4 | ipv6}
show adjacency <prefix> detail
test cef table consistency detail
Unchanged Cisco Express Forwarding show Commands
Feature Information for Cisco Express Forwarding Enhancements
Cisco Express Forwarding Enhancements: Removal of IP Fast Switching and Introduction of CLI Changes
First Published: July 11, 2008Last Updated: July 11, 2008The purpose of this document is to describe the changes based on the Cisco Express Forwarding infrastructure scalability enhancements that have been implemented to adapt to the evolution of the Internet and to support new platforms and features. The changes are the removal of IP fast switching and the introduction of command line interface (CLI) modifications.
This document lists Cisco Express Forwarding CLI commands that are removed, replaced, changed, and new. To help you transition to the new CLI format, the document illustrates the output for new commands and changed commands.
Enhancements to Cisco Express Forwarding enable it to operate with the Multiprotocol Label Switching (MPLS) Forwarding Infrastructure (MFI) and guarantee consistency across Cisco IOS release trains. Cisco Express Forwarding infrastructure changes were introduced and implemented in the Cisco IOS 12.2(25)S-based releases and were added for T releases in Cisco IOS Release 12.4(20)T.
Cisco Express Forwarding is an advanced Layer 3 IP switching technology. It optimizes network performance and scalability for all kinds of networks: those that carry small amounts of traffic and those that carry large amounts of traffic in complex patterns, such as the Internet, and networks characterized by intensive web-based applications or interactive sessions.
Finding Feature Information in This Module
Your Cisco IOS software release may not support all of the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To reach links to specific feature documentation in this module and to see a list of the releases in which each feature is supported, use the "Feature Information for Cisco Express Forwarding Enhancements" section.
Finding Support Information for Platforms and Cisco IOS and Catalyst OS Software Images
Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Contents
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Information About Cisco Express Forwarding Enhancements
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Information About Cisco Express Forwarding Enhancements
This document presents the following topics to explain the changes you will find with the implementation of the Cisco Express Forwarding enhancements. This information should be helpful as you transition to Cisco IOS software that includes the Cisco Express Forwarding and MFI enhancements.
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The fifth and sixth topics provide information about the CLI changes implemented as part of the Cisco Express Forwarding enhancements. In each section, the commands that are changed are listed, followed by an explanation of how they are changed. Sample command output is included in sections to compare "before" and "after" output information and to provide new output information.
The information about the commands is presented in the following order:
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Introduction of Cisco Express Forwarding Enhancements
Cisco Express Forwarding is at the heart of switching in every router. Improvements have been made to the Cisco Express Forwarding infrastructure to enhance and scale switching. Cisco Express Forwarding enhancements were introduced in Cisco IOS Release 12.2(25)S and first adopted by Cisco IOS 12.2(25)S-based releases. In Cisco IOS Release 12.4(20)T, the Cisco Express Forwarding enhancements were added for Cisco IOS 12.4(20)T releases and later T-based releases.
Table 1 lists the Cisco IOS releases and platforms that support the Cisco Express Forwarding enhancements and the changes described in this document.
Cisco Express Forwarding Enhancements for Cisco IOS Release 12.4(20)T
Cisco IOS Release 12.4(20)T incorporates the following Cisco Express Forwarding infrastructure changes:
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For information on MFI enhancements, see MPLS Infrastructure Changes: Introduction of MFI and Removal of MPLS LSC and LC-ATM Features.
The Cisco Express Forwarding infrastructure changes provide the following:
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No new features are introduced in Cisco IOS Release 12.4(20)T. However, some features that previously shipped with a Cisco IOS 12.2(25)S-based release are new to the Cisco IOS 12.4T release.
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Removal of Support for IPv4 Fast Switching
IPv4 fast switching is removed with the implementation of the Cisco Express Forwarding infrastructure enhancements for Cisco IOS 12.2(25)S-based releases and Cisco IOS Release 12.4(20)T. For these and later Cisco IOS releases, switching path are Cisco Express Forwarding switched or process switched. This makes the switching decision easier for future development of software features.
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Removed, Obsolete, and No Longer Supported Cisco Express Forwarding Commands
The following commands are obsolete and have been removed from Cisco IOS software with the present Cisco Express Forwarding enhancements:
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Table 2 lists the commands that replace the removed commands.
The following commands still exist, but are no longer supported in Cisco IOS software:
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Table 3 lists commands that still exist, but are no longer supported, and the commands that replaces the unsupported commands. You should start using the replacement commands.
Table 3 Replaced Cisco Express Forwarding Commands—Cisco Express Forwarding Enhancements Feature
ip cef event -log
monitor event-log cef event
ip cef interface event-log
monitor event-log cef interface
ip cef table event-log
monitor event-log cef ipv4
ip cef table consistency-check
cef table consistency-check
ip cef loadinfo
cef table output-chain
show cef events
show monitor event-trace cef events all
show cef drop
show {ip | ipv6} cef switching statistics [feature]1
show cef not-cef-switched
show {ip | ipv6} cef switching statistics [feature]
1 If you enter the optional feature keyword, the output shows per-feature drop and punt counters.
Cisco Express Forwarding CLI Command Output Changes
This section describes the CLI command output changes introduced with the Cisco Express Forwarding Enhancements feature. In some commands the output format is changed. In other commands, pieces of information are added or removed from the output. The output of the following commands is changed with this feature:
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For a full description of these commands, see the Cisco IOS IP Switching Command Reference and the Cisco IOS IPv6 Command Reference.
show ip cef summary
This feature provides the following changes to the output of the show ip cef summary command:
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Table 4 compares the show ip cef summary command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show ipv6 cef summary
This feature provides the following change to the output of the show ipv6 cef summary command:
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Table 5 compares the show ipv6 cef summary command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show ip cef internal
This feature provides the following changes to the output of the show ip cef internal command:
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Table 6 compares the show ip cef internal command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show ipv6 cef internal
This feature provides the following changes to the output of the show ipv6 cef internal command:
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The previous version of the command output is very similar to the output of the command after the Cisco Express Forwarding enhancements.
Table 7 compares the show ipv6 cef internal command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show ip cef detail
This feature provides the following changes to the output of the show ip cef detail command:
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show ipv6 cef detail
This feature provides the following change to the output of the show ipv6 cef detail command:
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Table 9 compares the show ipv6 cef detail command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show ip cef <prefix> internal
This feature provides the following changes to the output of the show ip cef prefix internal command:
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Table 10 compares the show ip cef prefix internal command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show ipv6 cef <prefix> internal
This feature provides the following changes to the output of the show ipv6 cef prefix internal command:
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The previous version of the command output is very similar to the output in the command after the Cisco Express Forwarding enhancements.
Table 11 compares the show ipv6 cef prefix internal command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show ip cef <prefix>
This feature provides the following changes to the output of the show ip cef prefix command:
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Table 12 compares the show ip cef prefix command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
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show ip cef exact-route <source> <destination> detail
This feature provides the following change to the output of the show ip cef exact-route source destination detail command:
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Table 13 compares the command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show ip cef exact-route <source> <destination>
This feature provides the following change to the output of the show ip cef exact-route source destination command:
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Table 14 compares the show ip cef exact-route source destination command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show ip cef adjacency <interface> <next-hop>
This feature provides the following change to the output of the show ip cef adjacency interface next-hop command:
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Table 15 compares the show ip cef adjacency interface next-hop command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show adjacency summary
This feature provides the following change to the output of the show adjacency summary command:
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Table 16 compares the show adjacency summary command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show adjacency detail
This feature provides the following change to the output of the show adjacency detail command:
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Table 17 compares the show adjacency detail command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show adjacency internal
This feature provides the following changes to the output of the show adjacency internal command:
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Table 18 compares the show adjacency internal command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show cef state
This feature provides the following changes to the output of the show cef state command:
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Table 19 compares the show cef state command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
Table 19 show cef state Command Output Before and After Cisco Express Forwarding Enhancements
1 This is the continuation of the output of the show cef state capabilities command.
show cef timers
This feature provides the following change to the output of the show cef timers command:
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Table 20 compares the show cef timers command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show ip cef epoch
This feature provides the following change to the output of the show ip cef epoch command:
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Table 21 compares the show ip cef epoch command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show ipv6 cef epoch
This feature provides the following change to the output of the show ipv6 cef epoch command:
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Table 22 compares the show ipv6 cef epoch command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show ip cef unresolved detail
This feature provides the following changes to the output of the show ip cef unresolved detail command:
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Table 23 compares the show ip cef unresolved detail command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show ipv6 cef unresolved detail
This feature provides the following changes to the output of the show ipv6 cef unresolved detail command:
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Table 24 compares the show ipv6 cef unresolved detail command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
show ipv6 cef non-recursive
This feature provides the following change to the output of the show ipv6 cef non-recursive command:
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Table 25 compares the show ipv6 cef non-recursive command output before ("Old" heading) and after ("New" heading) the Cisco Express Forwarding enhancements.
New Commands for the Cisco Express Forwarding Enhancements Feature
This section does not contain all new Cisco Express Forwarding commands. It contains only new commands introduced with the Cisco Express Forwarding enhancements to provide the same level of information that was available with the use of other commands before the Cisco Express Forwarding enhancements were implemented. Sample output is provided for the following new commands:
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show adjacency link {ipv4 | ipv6}
The show adjacency link ipv4 command and the show adjacency link ipv6 command display information about IPv4 and IPv6 traffic, respectively, in the Cisco Express Forwarding adjacency table or the hardware Layer 3-switching adjacency table.
Per-protocol and interface summary adjacency information was moved from the show adjacency summary command to the show adjacency link command.
Following is sample output of the show adjacency link ipv4 command.
Router# show adjacency link ipv4Protocol Interface AddressIP FastEthernet0/0 10.60.17.2(6)IP FastEthernet0/0 10.60.17.20(6)IP FastEthernet0/0 10.60.17.254(7)IP FastEthernet0/1 172.17.22.1(16)Following is sample output of the show adjacency link ipv6 command.
Router# show adjacency link ipv6Protocol Interface AddressIPV6 FastEthernet0/1 2001:2:22::1(6)IPV6 FastEthernet0/1 2001:2:22::2(3) (incomplete)IPV6 FastEthernet0/1 FE80::2D0:1FF:FEE4:6800(14)IPV6 Serial3/0 point2point(7)IPV6 Serial3/1 point2point(10show adjacency <prefix>
The show adjacency prefix command shows adjacency information for the specified prefix.
Following are sample outputs from the show adjacency prefix command for an IPv4 prefix and an IPv6 prefix:
Router# show adjacency 172.17.22.1/24Protocol Interface AddressIP FastEthernet0/1 172.17.22.1(16)Router# show adjacency 2001:2:22::1/64Protocol Interface AddressIPV6 FastEthernet0/1 2001:2:22::1(6)show adjacency <prefix> detail
The show adjacency prefix detail command provides additional adjacency information for a specified prefix.
Information about the adjacency epoch was removed from the show ip cef epoch and show ipv6 cef epoch commands and is available from the show adjacency prefix detail command.
Following are sample outputs from the show adjacency prefix detail command for an IPv4 prefix and an IPv6 prefix:
Router# show adjacency 172.17.22.1/24 detailProtocol Interface AddressIP FastEthernet0/1 172.17.22.1(16)0 packets, 0 bytesepoch 0sourced in sev-epoch 3Encap length 1400D001E4680000055FAF2C060800ARPRouter# show adjacency 2001:2:22::1/64 detailProtocol Interface AddressIPV6 FastEthernet0/1 2001:2:22::1(6)0 packets, 0 bytesepoch 0sourced in sev-epoch 3Encap length 1400D001E4680000055FAF2C0686DDIPv6 NDshow {ip | ipv6} cef tree
The show {ip | ipv6} cef tree command displays summary information about the underlying data structures representing the specified FIB tree.
Mtrie data structure information was removed from several commands for the implementation of the Cisco Express Forwarding enhancements. This command provides the Mtrie information removed from the show ip cef summary, show ip cef internal, and show ip cef detail commands.
Following is sample output for the show ip cef tree command:
Router# show ip cef treeVRF Default tree information:MTRIE/RTREE storing IPv4 addresses24 entries (24/0 fwd/non-fwd)Forwarding tree:Forwarding lookup routine: IPv4 mtrie 8-8-8-8 optimized33 inserts, 9 deletes8-8-8-8 stride patternshort mask protection enabled for <= 4 bits without process suspension24 leaves (672 bytes), 22 nodes (22880 bytes)25208 total bytesleaf ops: 33 inserts, 9 deletesleaf ops with short mask protection: 2 inserts, 1 deleteper-prefix length stats: lookup off, insert off, delete offrefcounts: 1356 leaf, 1324 nodenode pools:pool[C/8 bits]: 22 allocated (0 failed), 22880 bytesNon-Forwarding tree:38 inserts, 38 deletes0 leaves (0 bytes), 0 nodes (0 bytes)0 total bytestest cef table consistency detail
The test cef table consistency detail command displays recorded Cisco Express Forwarding consistency records found by the following detection mechanisms: lc-detect, scan-rib-ios, scan-ios-rib, scan-lc-rp, and scan-rp-lc. The scan-lc-rp and scan-rp-lc detection mechanisms are available only on routers with line cards. You can configure the Cisco Express Forwarding prefix consistency-detection mechanisms using the cef table consistency-check command.
This command provides output that replaces the output provided by the removed and obsolete show ip cef inconsistency records, show ip cef inconsistency now, and show ip cef inconsistency now detail commands.
Following is sample output for the test cef table consistency detail command:
Router# test cef table consistency detailfull-scan-rib-ios: Checking IPv4 RIB to FIB consistencyfull-scan-rib-ios: FIB checked 12 prefixes, and found 0 missing.full-scan-ios-rib: Checking IPv4 FIB to RIB consistencyfull-scan-ios-rib: Checked 12 FIB prefixes in 1 pass, and found 0 extra.full-scan-rp-lc: Sent 26 IPv4 prefixes to linecards in 1 passfull-scan-rp-lc: Initiated IPv4 FIB check on linecards..4..1..0..full-scan-rp-lc: FIB IPv4 check completed on linecards..1..0..4..full-scan-rp-lc: Linecard 4 checked 26 IPv4 prefixes (ignored 0). 0 inconsistent.full-scan-rp-lc: Linecard 1 checked 26 IPv4 prefixes (ignored 0). 0 inconsistent.full-scan-rp-lc: Linecard 0 checked 26 IPv4 prefixes (ignored 0). 0 inconsistent.full-scan-rib-ios: Checking IPv6 RIB to FIB consistencyfull-scan-rib-ios: FIB checked 16 prefixes, and found 5 missing.full-scan-ios-rib: Checking IPv6 FIB to RIB consistencyfull-scan-ios-rib: Checked 11 FIB prefixes in 1 pass, and found 0 extra.full-scan-rp-lc: Sent 11 IPv6 prefixes to linecards in 1 passfull-scan-rp-lc: Initiated IPv6 FIB check on linecards..4..1..0..full-scan-rp-lc: FIB IPv6 check completed on linecards..1..4..0..full-scan-rp-lc: Linecard 4 checked 11 IPv6 prefixes (ignored 0). 0 inconsistent.full-scan-rp-lc: Linecard 1 checked 11 IPv6 prefixes (ignored 0). 0 inconsistent.full-scan-rp-lc: Linecard 0 checked 11 IPv6 prefixes (ignored 0). 0 inconsistent.No IPv4 inconsistencies found, check took 00:00:01.444Warning: 5 IPv6 inconsistencies found, check took 00:00:01.240Unchanged Cisco Express Forwarding show Commands
Some Cisco Express Forwarding show commands related to the Cisco Express Forwarding enhancements were not changed with the introduction of the enhancements. The output of the following commands was not changed:
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Additional References
The following sections provide references related to the Cisco Express Forwarding Enhancements feature.
Related Documents
Description of Cisco Express Forwarding commands
Description of Cisco Express Forwarding IPv6 commands
Information on MFI enhancements
MPLS Infrastructure Changes: Introduction of MFI and Removal of MPLS LSC and LC-ATM Features
Technical Assistance
Feature Information for Cisco Express Forwarding Enhancements
Table 26 lists the release history for this feature.
Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
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Glossary
adjacency—A relationship formed between selected neighboring routers and end nodes for the purpose of exchanging routing information. Adjacency is based upon the use of a common media segment by the routers and nodes involved.
Cisco Express Forwarding—A Layer 3 switching technology. Cisco Express Forwarding can also refer to central Cisco Express Forwarding mode, one of two modes of Cisco Express Forwarding operation. Cisco Express Forwarding enables a Route Processor (RP) to perform express forwarding. Distributed Cisco Express Forwarding is the other mode of Cisco Express Forwarding operation.
distributed Cisco Express Forwarding—A type of Cisco Express Forwarding switching in which line cards (such as Versatile Interface Processor (VIP) line cards) maintain identical copies of the forwarding information base (FIB) and adjacency tables. The line cards perform the express forwarding between port adapters; this relieves the Route Switch Processor of involvement in the switching operation.
FIB—forwarding information base. A component of Cisco Express Forwarding. The router uses the FIB lookup table to make destination-based switching decisions during Cisco Express Forwarding operation. The router maintains a mirror image of the forwarding information in an IP routing table.
IDB—Interface Descriptor Block. An IDB is a special control structure internal to the Cisco IOS software that contains information such as the IP address, interface state, and packet statistics. Cisco IOS software maintains one IDB for each interface present on a platform and one IDB for each subinterface.
IPRM—IP Rewrite Manager. The IPRM is a module that manages the interaction between Cisco Express Forwarding, the IP Label Distributions Modules (LDM), and the Multiprotocol Label Switching (MPLS) Forwarding Infrastructure (MFI).
Mtrie—multiway tree. The Mtrie is a data structure in which routes are stored. The Mtrie is part of the IP lookup algorithm used in Cisco Express Forwarding.
prefix—The network address portion of an IP address. A prefix is specified by a network and mask and is generally represented in the format network/mask. The mask indicates which bits are the network bits. For example, 10.0.0.0/16 means that the first 16 bits of the IP address are masked, making them the network bits. The remaining bits are the host bits. In this example, the network number is 10.0.
RIB—Routing Information Base. A central repository of routes that contains Layer 3 reachability information and destination IP addresses or prefixes. The RIB is also known as the routing table.
RP—Route Processor. The processor module in the Cisco 7000 series routers that contains the CPU, system software, and most of the memory components that are used in the router. It is sometimes called a supervisory processor.
VRF—A Virtual Private Network (VPN) routing/forwarding instance. A VRF consists of an IP routing table, a derived forwarding table, a set of interfaces that use the forwarding table, and a set of rules and routing protocols that determine what goes into the forwarding table. In general, a VRF includes the routing information that defines a customer VPN site that is attached to a provider edge (PE) router.
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