11.7. Configuring Smart Link

Overview

Function Introduction

The Smart Link is a simple but practical technology of fast link protection. It is a solution specific to dual uplink networking to fulfill redundancy and fast migration of active and standby links.

Every smart-link group is included a pair of a layer 2 interfaces where one interface is configured to act as a standby to the other. The feature provides an alternative solution to the STP. Users can disable STP and still retain basic link redundancy. The feature also support load-balancing so than both interfaces simultaneously forward the traffic.

Principle Description

N/A

Configuration

The figure above is a typical smart-link application. The Switch1 and Switch2 are configured smart-link group. Switch3, Switch4 and Switch5 are configured smart-link flush receiver.

To configure smart-link group, some configuration should be configured before it.

VLANs should be configured.
MSTP instance should be configured.
Spanning-tree should be disabled in the interface.
About above configurations, please see the related references.

The following configuration should be operated on all switches if the switch ID is not specified.

step 1 Enter the configure mode

Switch# configure terminal

step 2 Enter the vlan configure mode and create the vlan

Switch(config)# vlan database
Switch(config-vlan)# vlan 2-20
Switch(config-vlan)# exit

step 3 Set the spanning tree mode and create mstp instance

Create the mstp instance on Switch1 and Switch2:

Switch(config)# spanning-tree mode mstp
Switch(config)# spanning-tree mst configuration
Switch(config-mst)# instance 1 vlan 1
Switch(config-mst)# instance 2 vlan 2
Switch(config-mst)# instance 3 vlan 3
Switch(config-mst)# instance 10 vlan 10
Switch(config-mst)# exit

step 4 Enter the interface configure mode and set the attributes of the interface

Interface configuration for Switch1 and Switch2:

Switch(config)# interface eth-0-13
Switch(config-if)# switchport mode trunk
Switch(config-if)# switchport trunk allowed vlan all
Switch(config-if)# spanning-tree port disable
Switch(config-if)# no shutdown
Switch(config-if)# exit
Switch(config)# interface eth-0-17
Switch(config-if)# switchport mode trunk
Switch(config-if)# switchport trunk allowed vlan all
Switch(config-if)# spanning-tree port disable
Switch(config-if)# no shutdown
Switch(config-if)# exit

Interface configuration for Switch3 and Switch4:

Switch(config)# interface eth-0-13
Switch(config-if)# switchport mode trunk
Switch(config-if)# no shutdown
Switch(config-if)# switchport trunk allowed vlan all
Switch(config-if)# smart-link flush receive control-vlan 10 password simple test
Switch(config-if)# exit
Switch(config)# interface eth-0-17
Switch(config-if)# no shutdown
Switch(config-if)# switchport mode trunk
Switch(config-if)# switchport trunk allowed vlan all
Switch(config-if)# smart-link flush receive control-vlan 10 password simple test
Switch(config-if)# exit

Interface eth-0-19 configuration for Switch3:

Switch(config)# interface eth-0-19
Switch(config-if)# switchport mode trunk
Switch(config-if)# no shutdown
Switch(config-if)# switchport trunk allowed vlan all
Switch(config-if)# exit

Interface eth-0-21 configuration for Switch4:

Switch(config)# interface eth-0-21
Switch(config-if)# switchport mode trunk
Switch(config-if)# no shutdown
Switch(config-if)# switchport trunk allowed vlan all
Switch(config-if)# exit

Interface configuration for Switch5:

Switch(config)# interface eth-0-19
Switch(config-if)# switchport mode trunk
Switch(config-if)# no shutdown
Switch(config-if)# switchport trunk allowed vlan all
Switch(config-if)# smart-link flush receive control-vlan 10 password simple test
Switch(config-if)# exit
Switch(config)# interface eth-0-21
Switch(config-if)# switchport mode trunk
Switch(config-if)# no shutdown
Switch(config-if)# switchport trunk allowed vlan all
Switch(config-if)# smart-ink flush receive control-vlan 10 password simple test
Switch(config-if)# exit

step 5 Create smart link group and set the attributes of the group

Create smart link group on Switch1 and Switch2:

Switch(config)# smart-link group 1
Switch(config-smlk-group)# interface eth-0-13 master
Switch(config-smlk-group)# interface eth-0-17 slave
Switch(config-smlk-group)# protected mstp instance 1
Switch(config-smlk-group)# protected mstp instance 2
Switch(config-smlk-group)# protected mstp instance 3
Switch(config-smlk-group)# protected mstp instance 10
Switch(config-smlk-group)# load-balance instance 3
Switch(config-smlk-group)# restore time 40
Switch(config-smlk-group)# restore enable
Switch(config-smlk-group)# flush send control-vlan 10 password simple test
Switch(config-smlk-group)# group enable
Switch(config-smlk-group)# exit

step 6 Disable the smart link relay function

Configure on Switch5:

Switch(config)# no smart-link relay enable

step 7 Exit the configure mode

Switch(config)# end

step 8 Validation

Display the result on Switch1.

Switch# show smart-link group 1
Smart-link group 1 information:
The smart-link group was enabled.
 ============================================================
Auto-restore:
state time count Last-time
enabled 40 0 N/A
 ============================================================
Protected instance: 1 2 3
Load balance instance: 3
Flush sender , Control-vlan ID: 10 Password:test
 ============================================================
INTERFACE:
Role Member DownCount Last-Down-Time FlushCount Last-Flush-Time
MASTER eth-0-13 0 N/A 0 N/A
SLAVE eth-0-17 0 N/A 0 N/A
 ============================================================
Instance states in the member interfaces:
A - ACTIVE , B -BLOCK , D-The interface is link-down
Map-instance-ID MASTER(eth-0-13) SLAVE(eth-0-17)
1 A B
2 A B
3 B A

Display the result on Switch2.

Switch# show smart-link group 1
Smart-link group 1 information:
The smart-link group was enabled.
 ============================================================
Auto-restore:
state time count Last-time
enabled 40 0 N/A
 ============================================================
Protected instance: 1 2 3
Load balance instance: 3
Flush sender , Control-vlan ID: 10 Password:test
 ============================================================
INTERFACE:
Role Member DownCount Last-Down-Time FlushCount Last-Flush-Time
MASTER eth-0-13 0 N/A 0 N/A
SLAVE eth-0-17 0 N/A 0 N/A
 ============================================================
Instance states in the member interfaces:
A - ACTIVE , B -BLOCK , D-The interface is link-down
Map-instance-ID MASTER(eth-0-13) SLAVE(eth-0-17)
1 A B
2 A B
3 B A

Display the result on Switch3.

Switch# show smart-link
Relay smart-link flush packet is enabled
Smart-link flush receiver interface:
eth-0-13 control-vlan:10 password:test
eth-0-17 control-vlan:10 password:test
Smart-link received flush packet number:0
Smart-link processed flush packet number:0
Smart link Group Number is 0.

Display the result on Switch4.

Switch# show smart-link
Relay smart-link flush packet is enabled
Smart-link flush receiver interface:
eth-0-13 control-vlan:10 password:test
eth-0-17 control-vlan:10 password:test
Smart-link received flush packet number:0
Smart-link processed flush packet number:0
Smart link Group Number is 0.

Display the result on Switch5.

Switch# show smart-link
Relay smart-link flush packet is disabled
Smart-link flush receiver interface:
eth-0-21 control-vlan:10 password: test
eth-0-19 control-vlan:10 password:test
Smart-link received flush packet number:0
Smart-link processed flush packet number:0
Smart link Group Number is 0.

Application cases

N/A

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