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 caveats and feature information, see Bug Search Tool and 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.
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.
When you are using the Cisco ASR 1001-X, the following restrictions apply for collecting traffic statistics for VLAN egress on sub-interfaces. Obtaining input/output counters using SNMP is unsupported. This is because the Cisco ASR 1001-X has a built-in SPA.
Restrictions that apply when obtaining traffic statistics for two types of interfaces are shown below:
Physical sub-interfaces
For the Cisco ASR 1001-X, statistics for the VLAN egress are available for physical sub-interfaces. The output counter is used from cpp, not from the built-in SPA hardware. To show VLAN egress statistics, use the show vlans vlan id command.
Example
# show vlans 10 VLAN ID: 10 (IEEE 802.1Q Encapsulation) > > Protocols Configured: Received: Transmitted: > IP 133 104
Port Channel sub-interfaces
For the Cisco ASR 1001-X, showing traffic statistics for the VLAN egress is not supported for port channel sub-interfaces.
cpp or the built-in SPA can not be used to give an output counter value for port channel sub-interfaces.
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.
1.
enable
2.
configure
terminal
3.
interface
port-channel
channel
-number
4.
lacp
fast-switchover
5.
lacp
max-bundle
1
6.
exit
7.
interface
tengigabitethernet
slot
/
port
/
number
8.
channel-group
1
mode
mode
9.
lacp
port-priority
priority
10.
exit
11.
interface
tengigabitethernet
slot
/
port
/
number
12.
channel-group
1
mode
mode
13.
lacp
port-priority
priority
14.
end
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.
1.
enable
2.
configure
terminal
3.
interface
tengigabitethernet
slot
/
port
/
number
4.
carrier-delay
msec
msec
5.
end
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
enable
Example: Router> enable |
Enables privileged EXEC mode.
|
| Step 2 |
configure
terminal
Example: Router# configure terminal |
Enters global configuration mode. |
| Step 3 |
interface
tengigabitethernet
slot
/
port
/
number
Example: Router(config)# interface tengigabitethernet 0/1/0 |
Enters interface configuration mode and opens the configuration for the specified interface. |
| Step 4 |
carrier-delay
msec
msec
Example: Router(config-if)# carrier-delay msec 11 |
Sets how long it takes to propagate the link status to other modules. |
| Step 5 |
end
Example: Router(config-if)# end |
Exits interface configuration mode. |
Use these show commands to verify the configuration and to display information about the port channel.
1.
enable
2.
show
running-config
interface
type
slot
/
port
/
number
3.
show
interfaces
port-channel
channel-number
etherchannel
4.
show
etherchannel
channel-number
port-channel
5.
end
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
enable
Example: Router> enable |
Enables privileged EXEC mode.
|
| Step 2 |
show
running-config
interface
type
slot
/
port
/
number
Example: Router# show running-config interface tengigabitethernet 0/0/0 |
Verifies the configuration.
|
| Step 3 |
show
interfaces
port-channel
channel-number
etherchannel
Example: Router# show interfaces port-channel 1 etherchannel |
Displays the bucket distribution currently in use. |
| Step 4 |
show
etherchannel
channel-number
port-channel
Example: Router# show etherchannel 1 port-channel |
Displays the port channel fast-switchover feature capability. |
| Step 5 |
end
Example: Router# end |
Exits privileged EXEC mode. |
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.|
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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