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EtherChannel flow-based limited 1:1 redundancy provides MAC, or layer 2, traffic protection to avoid higher layer protocols from reacting to single link failures and re-converging. To use EtherChannel flow-based limited 1:1 redundancy, you configure an EtherChannel with two ports (one active and one standby). If the active link goes down, the EtherChannel stays up and the system performs fast switchover to the hot-standby link. Depending on how you have the priorities set, when the failed link becomes operational again, the EtherChannel performs another fast switchover to revert to the original active link. if all port-priorities are the same, it will not revert, but remain on the current active link.
With 1:1 redundancy configured, only one link is active at any given time so all flows are directed over the active link.
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
EtherChannel flow-based limited 1:1 redundancy provides an EtherChannel configuration with one active link and fast switchover to a hot standby link. To use EtherChannel flow-based limited 1:1 redundancy, you configure a Link Aggregation Control Protocol (LACP) EtherChannel with two ports (one active and one standby). If the active link goes down, the EtherChannel stays up and the system performs fast switchover to the hot standby link. Depending on how the priorities of the links are set, when the failed link becomes operational again, the EtherChannel performs another fast switchover to revert to the original active link, or to the link with the higher priority.
For EtherChannel flow-based limited 1:1 redundancy to work correctly (especially the fast switchover capability) the feature must be enabled at both ends of the link.
To configure an LACP EtherChannel with two ports (one active and one standby), perform the following steps. This feature must be enabled at both ends of the link.
You can control which link is the primary active link by setting the port priority on the links used for the redundancy. To configure a primary link and enable the EtherChannel to revert to the original link, one link must have a higher port priority than the other and the LACP max-bundle must be set to 1. This configuration results in link 1 being active and link 2 being in hot standby state.
To prevent the switchover to revert, you can assign both links the same priority.
Optionally, you can control the speed of the switchover between the active and standby links by setting the carrier delay on each link. The carrier-delay command controls how long it takes for Cisco IOS to propagate the information about the links status to other modules.
Use these show commands to verify the configuration and to display information about the port channel.
This example shows how to configure a port channel for 1:1 link redundancy for equal priority ports so there is no preference which port is active.
Router# enable Router# configure terminal Router(config)# interface port-channel 2 Router(config-if)# ip address 10.1.1.1 255.255.0.0 Router(config-if)# negotiation auto Router(config-if)# lacp max-bundle 1 Router(config-if)# lacp fast-switchover Router(config)# interface Tengigabitethernet0/1/0 Router(config-if)# channel-group 2 mode active Router(config-if)# negotiation auto Router(config)# interface Tengigabitethernet 2/1/0 Router(config-if)# channel-group 2 mode active Router(config-if)# negotiation auto Router(config)# interface GigabitEthernet0/1/6 Router(config-if)# negotiation auto Router(config-if)# channel-group 19 mode active Router(config)# interface GigabitEthernet0/1/7 Router(config-if)# negotiation auto Router(config-if)# channel-group 19 mode active Router(config-if)# interface Port-channel19 Router(config-if)# ip address 10.19.1.1 255.255.255.0 Router(config-if)# no negotiation auto Router(config-if)# lacp fast-switchover Router(config-if)# lacp max-bundle 1 Router(config-if)# end
Notice in the show command display the priorities are the same value.
Router# show lacp internal
Flags: S - Device is requesting Slow LACPDUs
F - Device is requesting Fast LACPDUs
A - Device is in Active mode P - Device is in Passive mode
Channel group 19
LACP port Admin Oper Port Port
Port Flags State Priority Key Key Number State
Gi0/1/6 SA bndl 32768 0x13 0x13 0x47 0x3D
Gi0/1/7 FA hot-sby 32768 0x13 0x13 0x48 0x7
This example shows how to configure an LACP EtherChannel with 1:1 redundancy. GigabitEthernet 0/1/7 is the active link, because it is configured with a lower number which give it a higher port priority.
Router# configure terminal Router(config)# interface GigabitEthernet0/1/6 Router(config-if)# lacp port-priority 32767 Router(config-if)# exit Router(config)# interface GigabitEthernet0/1/7 Router(config-if)# lacp fast-switchover Router(config-if)# lacp max-bundle 1 Router(config-if)# negotiation auto Router(config-if)# channel-group 19 mode active
In this show display, notice that the bundled link is set at a higher priority. This will ensure that the bundled link is used as the first active link in the standby configuration.
Router# show lacp internal
Flags: S - Device is requesting Slow LACPDUs
F - Device is requesting Fast LACPDUs
A - Device is in Active mode P - Device is in Passive mode
Channel group 19
LACP port Admin Oper Port Port
Port Flags State Priority Key Key Number State
Gi0/1/6 FA hot-sby 32768 0x13 0x13 0x47 0x7
Gi0/1/7 SA bndl 32767 0x13 0x13 0x48 0x3D
The following sections provide references related to the EtherChannel Flow-based Limited1:1 Redundancy feature.
Related Topic |
Document Title |
---|---|
Cisco IOS commands |
Cisco IOS Master Commands List, All Releases |
LAN Switching commands |
Cisco IOS LAN Switching Command Reference |
Standard |
Title |
---|---|
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature. |
-- |
MIB |
MIBs Link |
---|---|
No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature. |
To locate and download MIBs for selected platforms, Cisco IOS XE software releases, and feature sets, use Cisco MIB Locator found at the following URL: |
RFC |
Title |
---|---|
No new or modified RFCs are supported by this feature, and support for existing standards has not been modified by this feature. |
-- |
Description |
Link |
---|---|
The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies. To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds. Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. |
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 1 | Feature Information for EtherChannel Flow-based Limited 1:1 Redundancy |
Feature Name |
Releases |
Feature Information |
---|---|---|
EtherChannel Flow-Based Limited 1:1 Redundancy |
Cisco IOS XE Release 2.4 |
EtherChannel flow-based limited 1:1 redundancy provides MAC, or layer 2, traffic protection to avoid higher layer protocols from reacting to single link failures and re-converging. To use EtherChannel flow-based limited 1:1 redundancy, you configure an EtherChannel with two ports (one active and one standby). If the active link goes down, the EtherChannel stays up and the system performs fast switchover to the hot-standby link. Depending on how you have the priorities set, when the failed link becomes operational again, the EtherChannel performs another fast switchover to revert to the original active link. if all port-priorities are the same, it will not revert, but remain on the current active link. No commands were modified or created to support this feature. |
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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.