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Operation Manual VRRPH3C S9500 Series Routing Switches Table of Contents
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Table of Contents
Chapter 1 VRRP Configuration ....................................................................................................1-11.1 Introduction to VRRP.........................................................................................................1-11.2 Configuring VRRP .............................................................................................................1-2
1.2.1 Configuring the Function of Pinging the Virtual IP Address.... ................................ 1-31.2.2 Configuring the TTL Value Check for VRRP Packets............................................. 1-31.2.3 Configuring the Mapping Mode between Virtual IP Address and MAC Address ............ 1-31.2.4 Configuring a Virtual IP Address............................................................................. 1-41.2.5 Configuring a Priority for a Switch in the VRRP Group........................................... 1-41.2.6 Configuring Preemption and Delay for a Switch in a VRRP Group ........................ 1-51.2.7 Configuring Authentication Type and Authentication Key....................................... 1-61.2.8 Configuring the Interval for Sending VRRP Packets on the Master ....................... 1-71.2.9 Configuring the Switch to Track a Specified Interface ............................................ 1-71.2.10 Configuring VRRP Link Monitoring ....................................................................... 1-81.2.11 Configuring IFM Tracking......................................................................................1-91.2.12 Configuring the Fast Switch Function for a Virtual Router.................................. 1-10
1.3 Displaying and Debugging VRRP....................................................................................1-111.4 VRRP Configuration Examples........................................................................................1-12
1.4.1 Single VRRP Group Configuration Example......................................................... 1-121.4.2 VRRP Interface Tracking Configuration Example................................................. 1-131.4.3 VRRP Link Monitoring Configuration Example ..................................................... 1-141.4.4 IFM Tracking Configuration Example.................................................................... 1-161.4.5 Multiple Virtual Routers Configuration Example ................................................... 1-18
1.5 Troubleshooting VRRP....................................................................................................1-19
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Chapter 1 VRRP Configuration
When configuring VRRP, go to these sections for information you are interested in:
Introduction to VRRP
Configuring VRRP
Displaying and Debugging VRRP
VRRP Configuration Examples
Troubleshooting VRRP
1.1 Introduction to VRRP
The Virtual Router Redundancy Protocol (VRRP) is a fault-tolerant protocol. In general,
a default route (for example, 10.100.10.1 as shown in the following internetworking
diagram) is configured for every host on the network, so that the packets destined to
some other network segment from the hosts will go through the default route to the
Layer 3 Switch. If Switch is down, all the hosts taking Switch as the next-hop will be
disconnected from the external network.
Ethernet
Switch
Host 1 Host 2 Host 3
10 .10 0.1 0.7 1 0.1 00 .10 .8 10.100.10.9
10.100.10.1
Network
Figure 1-1 Network diagram for LAN
VRRP, designed for LANs with multicast and broadcast capabilities (such as Ethernet)
settles the above problem. VRRP integrates a group of LAN switches (including a
Master and several Backups) into a virtual router. The diagram below is taken as an
example to explain how VRRP works.
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Master
Virtual IP address10.100.10.1
Backup
Virtual IP address10.100.10.1
Actual IP address10.100.10.2 Actual IP address10.100.10.3
Ethernet
Host 1 Host 2 Host 3
10 .10 0.1 0.7 10 .10 0.10.8 10 .10 0.1 0.9
Network
Figure 1-2 Network diagram for virtual router
This virtual router has its own IP address: 10.100.10.1 (which can be the interface
address of a switch within the virtual router). The switches within the virtual router have
their own IP addresses (such as 10.100.10.2 for the Master switch and 10.100.10.3 for
the Backup switch). The hosts on the LAN only know the IP address of this virtual router
10.100.10.1 (usually called as virtual IP address of the virtual router), but not the
specific IP addresses 10.100.10.2 of the Master switch and 10.100.10.3 of the Backup
switch. A default route with the next hop 10.100.10.1 is configured on the hosts.
Therefore, hosts within the network will communicate with the external network through
this virtual router. If the Master switch in the virtual group breaks down, another Backup
switch will function as the new Master switch to continue serving the hosts without any
interruption.
1.2 Configuring VRRP
The following sections describe the VRRP configuration tasks:
Configuring the Function of Pinging the Virtual IP Address
Configuring the TTL Value Check for VRRP Packets
Configuring the Mapping Mode between Virtual IP Address and MAC Address
Configuring a Virtual IP Address
Configuring a Priority for a Switch in the VRRP Group
Configuring Preemption and Delay for a Switch in a VRRP Group
Configuring Authentication Type and Authentication Key
Configuring the Interval for Sending VRRP Packets on the Master
Configuring the Switch to Track a Specified Interface
Configuring VRRP Link Monitoring
Configuring IFM Tracking
Configuring the Fast Switch Function for a Virtual Router
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1.2.1 Configuring the Function of Pinging the Virtual IP Address
This task is to enable/disable the function of pinging the IP address of the virtual router.
With this function enabled, you can ping the virtual IP address of the virtual router or
telnet to the virtual IP address of the virtual router.
Perform the following configuration in system view to enable/disable the ping function:
To do Use the command
Enable the ping function vrrp ping-enable
Disable to ping function undo vrrp ping-enable
By default, the ping function is enabled, that is, you can ping or telnet to the virtual IP
address of the virtual router.
You should enable the ping function before configuring the virtual router. If VRRP is
already configured on the switch, it is not allowed to modify the configuration.
1.2.2 Configuring the TTL Value Check for VRRP Packets
This task is to enable/disable the TTL value check for VRRP packets on the backup
switch. The TTL value must be 225. If the backup switch finds the TTL of a VRRP
packet is not 225, the packet will be discarded.
Perform the following configuration in VLAN interface view to enable/disable the TTL
value check for VRRP packets:
To do Use the command
Disable the TTL value check for VRRP packets vrrp un-check ttl
Enable the TTL value check for VRRP packets undo vrrp un-check ttl
1.2.3 Configuring the Mapping Mode between Virtual IP Address and MAC
Address
This task is to configure the mapping mode between virtual lP address and MAC
address. In VRRP, the virtual IP address of the virtual router corresponds to the virtual
MAC address, to ensure correct data forwarding.
Depending on the chips installed, some switches support mapping one virtual IP
address to multiple MAC addresses.
S9500 series not only guarantee correct data forwarding in the subnet, but also allow
you to specify a mapping mode, either virtual IP address to real MAC address mapping
or virtual IP address to virtual MAC address mapping.
Perform the following configuration in system view to configure IP-to-MAC mappings:
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To do Use the command
Specify a mapping mode for the virtualIP address
vrrp method { real-mac | virtual-mac }
Restore the default undo vrrp method
By default, the virtual IP address of the virtual router corresponds to the virtual MAC
address.
You should perform this configuration only before configuring the virtual router.
1.2.4 Configuring a Virtual IP Address
This task is to assign a virtual IP address to a virtual router or remove an assigned
virtual IP address.
Perform the following configuration in VLAN interface view to add/delete a virtual IP
address:
To do Use the command
Assign a virtual IP address to a virtualrouter
vrrp vridvirtual-router-idvirtual-ipvirtual-address
Delete a virtual IP addressundo vrrp vridvirtual-router-id[ virtual-ipvirtual-address]
The virtual-router-idranges from 1 to 255.
The virtual-address can be an unused address in the network segment where the
virtual router resides, or the IP address of an interface in the virtual router. If the virtual
address is the same as the real IP address of a member switch in the virtual router, the
switch is called an IP Address Owner. When assigning an IP address to a nonexistent
virtual router, the system will create a new virtual router accordingly. When adding a
new address to an existing virtual router, the system will directly add it into the virtual IP
address list.
After the last virtual IP address is removed from the virtual router, the whole virtualrouter will also be removed. That is, there is no virtual router on the interface any more
and any configuration of it is invalid accordingly.
1.2.5 Configuring a Priority for a Switch in the VRRP Group
The status of each switch in the virtual router will be determined by its priority in VRRP.
The switch with the highest priority will become the master.
Perform the following configuration in VLAN interface view to configure a priority for the
switch in the virtual router:
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To do Use the command
Configure a priority for the switch in thevirtual router.
vrrp vrid virtual-router-idprioritypriority
Remove the priority setting of the switch undo vrrp vrid virtual-router-idpriority
The priority ranges from 0 to 255. The greater the number, the higher the priority.
However the value can only be taken from 1 to 254. The priority 0 is reserved for special
use and priority 255 is reserved for the IP address owner by the system.
By default, the priority is 100.
Note:The priority for IP address owner is always 255, which cannot be configured.
1.2.6 Configuring Preemption and Delay for a Switch in a VRRP Group
Once a switch in the VRRP group becomes the master, as long as it still functions
properly, other switches, even configured with a higher priority later, cannot become the
master unless they are configured to work in preemption mode. The switch in
preemption mode will become the master switch, when it finds its own priority is higherthan that of the current master switch. Accordingly, the former master switch will
become a backup switch.
Together with the preemption setting, a delay can also be set. In this way, a backup will
wait for a period of time before becoming the new master. In an unstable network if the
backup switch has not received the packets from the master switch punctually, it will
become the master switch. However, the receiving failure may be due to network
congestion, instead of the malfunction of the master switch. In this case, the backup will
receive the packets after a while. The delay setting can thereby avoid the frequent
status changing.
Perform the following configuration in VLAN interface view to configure preemption and
delay for a switch within a virtual router:
To do Use the command
Enable the preemption modeand configure a delay.
vrrp vrid virtual-router-idpreempt-mode [ timerdelaydelay-value]
Disable the preemption mode. undo vrrp vridvirtual-router-idpreempt-mode
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The delay in seconds ranges from 0 to 255. By default, the preemption mode is enabled
with a delay of 0 seconds.
Note:If preemption mode is disabled, the delay will automatically become 0 seconds.
1.2.7 Configuring Authentication Type and Authentication Key
VRRP provides following authentication types:
simple: Simple character authentication
md5: MD5 authentication
In a network under possible security threats, the authentication type can be set to
simple. Then the switch will add the authentication key into the VRRP packets before
transmitting it. The receiver will compare the authentication key of the packet with the
locally configured one. If they are the same, the packet will be taken as a true and legal
one. Otherwise it will be regarded as an illegal packet and discarded. In this case, an
authentication key not exceeding 8 characters should be configured.
In a totally unsafe network, the authentication type can be set to md5. The switch will
use the authentication type and MD5 algorithm provided by the Authentication Header
to authenticate the VRRP packets. In this case an authentication key not exceeding 8
characters should be configured.
Those packets failing to pass the authentication will be discarded and a trap packet will
be sent to the network management system.
Perform the following configuration in VLAN interface view to configure authentication
type and authentication key:
To do Use the command
Configure authentication type andauthentication key
vrrp vrid virtual-router-idauthentication-mode { md5 | simple } key
Remove the authentication typeand authentication key
undo vrrp vrid virtual-router-idauthentication-mode
By default, no authentication is performed.
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Note:The same authentication type and authentication key should be configured for all VLAN
interfaces that belong to the virtual router.
1.2.8 Configuring the Interval for Sending VRRP Packets on the Master
The master switch advertises its normal operation state to the backup switch by
sending VRRP packets regularly (at adver-interval). And the backup switch only
receives VRRP packets. If the backup has not received any VRRP packet from the
master within a period of time (specified by master-down-interval), it will consider the
master as down, and then take its place and become the Master.
You can use the following command to set a timer and adjust the interval (adver-interval)
at which Master transmits VRRP packets. The master-down-intervalof the Backup
switch is three times that of the adver-interval. The excessive network traffic or the
differences between different switch timers will result in master-down-intervaltiming out
and state changing abnormally. Such problems can be solved through prolonging the
adver-intervaland preemption delay time. adver-intervalis measured in seconds.
Perform the following configuration in VLAN interface view to configure the interval for
the master to send VRRP packets:
To do Use the commandConfigure the interval for the master tosend VRRP packets
vrrp vrid virtual-router-idtimeradvertiseadver-interval
Restore the defaultundo vrrp vrid virtual-router-idtimeradvertise
By default, adver-intervalis 1.
Note:
You must configure the same interval for switches within the VRRP group.
1.2.9 Configuring the Switch to Track a Specified Interface
The VRRP interface track function extends the function of a VRRP group. It enables
redundancy between VRRP interfaces, and between other switch interfaces.
You can use the following command to track a specified interface on the master switch.
If the interface is down, the priority of the switch will reduce automatically by the value
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specified by value-reduced. Then the backup switch with the highest priority becomes
the new master.
Perform the following configuration in VLAN interface view to configure the switch to
track a specified interface:
To do Use the command
Configure the switch to track a specifiedinterface
vrrp vrid virtual-router-idtrackinterface vlan-interface vlan-id[ reducedvalue-reduced]
Stop tracking the specified interfaceundo vrrp vridvirtual-router-idtrackinterfacevlan-interfacevlan-id
By default, priority is reduced by 10.
Note: If the switch is an IP address owner, its interfaces cannot be tracked.
If the interface is up again, the corresponding priority of the switch, will be restored
automatically.
On each virtual router, a maximum of eight interfaces can be tracked.
1.2.10 Configuring VRRP Link Monitoring
This task allows you to configure the backup VRRP device to monitor the link to the
master. When the monitored link goes down, the backup device immediately switches
to the master state.
The monitored link can be an Ethernet interface, or a manual aggregation group or
static aggregation group.
If the monitored link is an Ethernet interface, the backup device immediately switches
to the master state when the link goes down; if the monitored link is an aggregation
group, the backup device switches to the master state after all the ports in the
aggregation group go down.
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Caution:
Before you configure VRRP link monitoring, it is required that no physical loop exists
and the spanning tree protocol (STP) is not enabled on the network.
If all the physical links in between are down, the backup device considers that the
master device is down, and then the backup device switches to the master state. At
this time, two master devices may exist, and you need to ensure communication
through networking.
Make sure that all the links between the master and backup devices are monitored.
Perform the following configuration in VLAN interface view to configure the switch to
monitor a specified link:
To do Use the command
Configure the device tomonitor the specifiedlink
vrrp vrid virtual-router-idmonitor { interfaceinterface-type interface-number| link-aggregationgroup group-id}
Disable link monitoring undo vrrp vrid virtual-router-idmonitor
By default, link monitoring is disabled.
Note: When you configure the device to monitor a specified interface, the interface cannot
belong to any aggregation group (including dynamic aggregation groups).
After you configure the device to monitor an aggregation group, the aggregation
group cannot be removed directly.
You cannot configure the device to monitor multiple links.
After you configure the device to monitor a specified link, you need to use a board
that supports reporting connection failures and configure the link-status hold 0
command globally to meet the performance requirements.
1.2.11 Configuring IFM Tracking
As a special card on softswitch devices, the IP forwarding module (IFM) is the portal of
softswitch, which is used to distribute IP signals. The disconnection with the IFM means
the termination of softswitch; therefore, the reliability of IFM has great importance.
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Figure 1-3 Network diagram for IFM devices
As shown in Figure 1-3, the two Layer 3 switches form a VRRP group. Each switch is
enabled to track the status of the corresponding IFM device through the OAM module.
When receiving signals from the IFM device, the priority of the corresponding interface
on a switch will increase by the value specified by value-increased. The switch with a
higher priority becomes the master. When the link of the master is down, the priority will
decrease by a specified value. As a result, the backup will have a higher priority and
become the master switch. Thus, the cooperation between IFM and VRRP through
OAM is implemented.
Perform the following configuration in VLAN interface view to enable/disable IFM
tracking:
To do Use the command
Enable IFM tracking vrrp vrid virtual-router-idtrack ifm [ increasedvalue-increased]
Disable IFM tracking undo vrrp vridvirtual-router-idtrackifm
By default, the value of the value-increasedargument is 2.
1.2.12 Configuring the Fast Switch Function for a Virtual Router
In VRRP, a backup device can switch to the master state after the specified timer
expires. This mechanism causes delay in state switching and is not applicable to
network environments that require fast state switching because it may interrupt traffic
temporarily. To solve this problem, S9500 series switches support the fast switch
function for the virtual router.
If the uplink virtual interface tracked by the master goes down, the master device
immediately decreases its priority and sends an advertisement packet.
Upon receiving the advertisement packet, the backup device compares the priority
in the packet with that of its own. If the backup device has a higher priority, it
switches to the master state immediately.
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Perform the following configuration in VLAN interface view to enable/disable the fast
switch function for a virtual router:
To do Use the command
Enable the fast switch functionfor a virtual router
vrrp vrid virtual-router-idfast-switch
Disable the fast switchfunction for the virtual router
undo vrrp vridvirtual-router-idfast-switch
By default, the fast switch function is disabled for a virtual router.
1.3 Displaying and Debugging VRRP
To do Use the command Remarks
Display VRRP stateinformation
displayvrrp[ interfacevlan-interface interface-number[ virtual-route-identifierifm| ifm |vrid virtual-router-id] ]
Display the configurationinformation of theVRRP-enabled IFMdevice
display vrrp ifm
Display VRRP statistics
information
display vrrpstatistics[ interfaceinterface-type interface-number[ vrid virtual-router-id] ]
Display VRRP detailedinformation
display vrrp verbose [ interfacetype number[ vridvirtual-router-id] ]
Available in anyview
Clear the statisticsinformation about VRRP
reset vrrp statistics [ interfaceinterface-type interface-number[ vrid virtual-router-id]]
Enable VRRP debuggingdebugging vrrp { state | packet |error }
Disable VRRP debuggingundo debugging vrrp { state |packet | error }
Available in userview
By default, VRRP debugging is disabled.
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1.4 VRRP Configuration Examples
1.4.1 Single VRRP Group Configuration Example
I. Network requirements
Host A takes the VRRP virtual router containing switch A and switch B as its default
gateway to access host B on the Internet.
It is required that:
The virtual router ID is 1;
The virtual IP address is 202.38.160.111;
Switch A is the master and switch B is the backup:
Preemption is allowed.
II. Network diagram
Virtual IP address:
202.38.160.111
Switch_A
Host A
202.38.160.3
VLAN- interface2: 202.38.160.1
Switch_B
VLAN-interface2: 202.38.160.2
VLAN-- interface3: 10.100.10.2
Host B
10.2.3.1
Internet
Figure 1-4 Network diagram for VRRP configuration
III. Configuration procedure
1) Configure switch A
# Configure VLAN 2.
[LSW-A] vlan 2
[LSW-A-vlan2] interface vlan 2
[LSW-A-vlan-interface2] ip address 202.38.160.1 255.255.255.0
[LSW-A-vlan-interface2] quit
# Configure VRRP.
[LSW-A] vrrp ping-enable
[LSW-A] interface vlan 2
[LSW_A-vlan-interface2] vrrp vrid 1 virtual-ip 202.38.160.111
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[LSW_A-vlan-interface2] vrrp vrid 1 priority 110
[LSW-A-vlan-interface2] vrrp vrid 1 preempt-mode
2) Configure switch B
# Configure VLAN2.
[LSW-B] vlan 2
[LSW-B-vlan2] interface vlan 2
[LSW-B-vlan-interface2] ip address 202.38.160.2 255.255.255.0
[LSW-B-vlan-interface2] quit
# Configure VRRP.
[LSW-B] vrrp ping-enable
[LSW-B] interface vlan 2
[LSW-B-vlan-interface2] vrrp vrid 1 virtual-ip 202.38.160.111
[LSW-B-vlan-interface2] vrrp vrid 1 preempt-mode
The virtual router can be used soon after configuration. Host A can be configured with
the default gateway 202.38.160.111.
Under normal conditions, switch A functions as the gateway. Once switch A breaks
down, switch B will function as the gateway instead.
Configure the preemption mode for switch A, so that it can become the master again
after recovery.
1.4.2 VRRP Interface Tracking Configuration Example
I. Network requirements
See Figure 1-4. If the interface of switch A connected to the Internet is down, switch B
should function as the gateway. This can be implemented by tracking the
corresponding interface.
The virtual router ID is 1. In addition, the MD5 authentication and VRRP packet sending
interval are configured.
II. Network diagram
See Figure 1-4.
III. Configuration procedure
1) Configure switch A
# Configure VLAN2.
[LSW-A] vlan 2
[LSW-A-vlan2] interface vlan 2
[LSW-A-vlan-interface2] ip address 202.38.160.1 255.255.255.0
[LSW-A-vlan-interface2] quit
# Enable the function to ping the virtual IP address of the virtual router.
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[H3CLSW-A ] vrrp ping-enable
# Create the VRRP virtual router.
[LSW-A] interface vlan 2
[LSW_A-vlan-interface2] vrrp vrid 1 virtual-ip 202.38.160.111
# Set the priority for the virtual router.
[LSW_A-vlan-interface2] vrrp vrid 1 priority 110
# Set the authentication mode and authentication key for the virtual router.
[LSW_A-vlan-interface2] vrrp vrid 1 authentication-mode md5 switch
# Configure the interface to send VRRP packets every 5 seconds.
[LSW_A-vlan-interface2] vrrp vrid 1 timer advertise 5
# Track VLAN-interface 3.
[LSW_A-vlan-interface2] vrrp vrid 1 track interface vlan-interface 3 reduced
30
2) Configure switch B
# Configure VLAN2.
[LSW-B] vlan 2
[LSW-B-vlan2] interface vlan 2
[LSW-B-vlan-interface2] ip address 202.38.160.2 255.255.255.0
[LSW-B-vlan-interface2] quit
# Enable the function to ping the virtual IP address of the virtual router.
[H3CLSW-B] vrrp ping-enable
# Create the virtual router.
[LSW-B] interface vlan 2
[LSW_B-vlan-interface2] vrrp vrid 1 virtual-ip 202.38.160.111
# Set the authentication mode and authentication key for the virtual router.
[LSW_B-vlan-interface2] vrrp vrid 1 authentication-mode md5 switch
# Configure the interface to send VRRP packets every five seconds.
[LSW_B-vlan-interface2] vrrp vrid 1 timer advertise 5
Under normal conditions, switch A functions as the gateway. Once VLAN-interface 3 of
switch A is down, its priority will be reduced by 30, lower than that of switch B so that
switch B will become the master.
When VLAN-interface 3 of switch A recovers, it will become the master again.
1.4.3 VRRP Link Monitoring Configuration Example
I. Network requirements
As shown in the figure below:
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No physical loops exist between Switch A, Switch B and Host Server, and STP is
not enabled.
Switch A is the master while Switch B is the backup. No physical link is available
between Switch A and Host Server.Normally, Switch A acts as the gateway. The traffic sent from Host Server is forwarded
at Layer 2 through Switch B to Switch A which then forwards the traffic at Layer 3 to the
IP network.
It is required to configure Switch B to monitor the link to Switch A. If Switch A fails or the
link between Switch A and Switch B fails, Switch B becomes the master and acts as the
gateway instead of Switch A. Then, the traffic from Host Server is forwarded to the IP
network directly through Switch B. The state switching delay should be in milliseconds.
II. Network diagram
Figure 1-5 Network diagram for VRRP configuration
III. Configuration procedure
1) Configure Switch A
# Configure VLAN 2.
system-view
[LSW-A] vlan 2
[LSW-A-vlan2] interface vlan 2
[LSW-A-vlan-interface2] ip address 10.1.1.1 255.255.255.0
[LSW-A-vlan-interface2] quit
# Enable pinging the virtual IP address of the virtual router.
[LSW-A ] vrrp ping-enable
# Create virtual router 1.
[LSW-A] interface vlan 2
[LSW-A-vlan-interface2] vrrp vrid 1 virtual-ip 10.1.1.3
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# Set the VRRP priority for Switch A.
[LSW-A-vlan-interface2] vrrp vrid 1 priority 110
2) Configure Switch B
# Configure VLAN 2.
system-view
[LSW-B] vlan 2
[LSW-B-vlan2] interface vlan 2
[LSW-B-vlan-interface2] ip address 10.1.1.2 255.255.255.0
[LSW-B-vlan-interface2] quit
# Enable pinging the virtual IP address of the virtual router.
[LSW-B] vrrp ping-enable
# Create virtual router 1.[LSW-B] interface vlan 2
[LSW-B-vlan-interface2] vrrp vrid 1 virtual-ip 10.1.1.3
# Enable Switch B to monitor interface Ethernet 2/1/1.
[LSW-B-vlan-interface2] vrrp vrid 1 monitor interface Ethernet 2/1/1
[LSW-B-vlan-interface2] quit
# Configure the global link state holdtime.
[LSW-B] link-status hold 0
1.4.4 IFM Tracking Configuration Example
I. Network requirements
As shown in the following figure, an IFM softswitch device is attached to a switch.
It is required to configure the two switches as a VRRP group and configure IFM tracking
to track the IFM devices through OAM. A switch that can receive signals from the
corresponding IFM device increases its priority with a specified value to influence
master switch election.
II. Network diagram
Figure 1-6 Network diagram for IFM tracking
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III. Configuration procedure
1) Configure Switch A
# Configure VLAN 2.
[Switch A] vlan 2
[Switch A-vlan2] interface vlan-interface 2
[Switch A-Vlan-interface2] ip address 202.38.160.1 255.255.255.0
[Switch A-Vlan-interface2] quit
# Enable OAM.
[Switch A] Ethernet3/1/1
[Switch A-Ethernet3/1/1] oam ethernet mode passive
[Switch A-Ethernet3/1/1] oam ethernet enable
[Switch A-Ethernet3/1/1] quit
# Enable the function of pinging the virtual IP address of the virtual router.
[Switch A] vrrp ping-enable
# Configure the virtual router.
[Switch A] interface vlan-interface 2
[Switch A-Vlan-interface2] vrrp vrid 1 virtual-ip 202.38.160.111
# Set the priority of the virtual router.
[Switch A-Vlan-interface2] vrrp vrid 1 priority 105
# Set the authentication mode and authentication key for the virtual router.
[Switch A-Vlan-interface2] vrrp vrid 1 authentication-mode md5 switch
# Configure IFM tracking, and set the increased value to 10.
[Switch A-Vlan-interface2] vrrp vrid 1 track ifm increased 10
2) Configure Switch B
# Configure VLAN2.
[Switch B] vlan 2
[Switch B-vlan2] interface vlan-interface 2
[Switch B-Vlan-interface2] ip address 202.38.160.2 255.255.255.0
[Switch B-Vlan-interface2] quit
# Enable OAM.
[Switch B] Ethernet3/1/1
[Switch B-Ethernet3/1/1] oam ethernet mode passive
[Switch B-Ethernet3/1/1] oam ethernet enable
[Switch B-Ethernet3/1/1] quit
# Enable the function to ping the virtual IP address of the virtual router.
[Switch B] vrrp ping-enable
# Create the virtual router.
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[Switch B] interface vlan 2
[Switch B-Vlan-interface2] vrrp vrid 1 virtual-ip 202.38.160.111
# Set the authentication mode and authentication key for the virtual router.
[Switch B-Vlan-interface2] vrrp vrid 1 authentication-mode md5 switch
# Configure IFM tracking, and set the increased value to 10.
[Switch B-Vlan-interface2] vrrp vrid 1 track ifm increased 10
Note:Switch A acts as the gateway in normal cases. When Switch B tracks the state of the
IFM device being Master through OAM, the priority of Switch B will be increased by 10,
greater than that of Switch A (105), and Switch B will turn the Master and act as the
gateway.
1.4.5 Multiple Virtual Routers Configuration Example
I. Network requirements
A switch can function as a backup switch for multiple virtual routers to implement load
balancing. See Figure 1-4. For example, Switch A, the master switch of virtual router 1,
can be the backup switch for virtual router 2, and Switch B can be the backup switch forvirtual router 1. Some hosts employ virtual router 1 as the gateway, while others employ
virtual router 2 as the gateway. In this way, both load balancing and backup are
implemented.
II. Network diagram
Refer to Figure 1-4.
III. Configuration procedure
1) Configure switch A
# Configure VLAN2.
[LSW-A] vlan 2
[LSW-A-vlan2] interface vlan 2
[LSW-A-vlan-interface2] ip address 202.38.160.1 255.255.255.0
# Create virtual router 1.
[LSW_A-vlan-interface2] vrrp vrid 1 virtual-ip 202.38.160.111
# Set the priority for the virtual router.
[LSW_A-vlan-interface2] vrrp vrid 1 priority 150
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# Create virtual router 2.
[LSW_A-vlan-interface2] vrrp vrid 2 virtual-ip 202.38.160.112
2) Configure switch B
# Configure VLAN2.
[LSW-B] vlan 2
[LSW-B-vlan2] interface vlan 2
[LSW-B-vlan-interface2] ip address 202.38.160.2 255.255.255.0
# Create virtual router 1.
[LSW_B-vlan-interface2] vrrp vrid 1 virtual-ip 202.38.160.111
# Create virtual router 2.
[LSW_B-vlan-interface2] vrrp vrid 2 virtual-ip 202.38.160.112
# Set the priority for the virtual router.
[LSW_B-vlan-interface2] vrrp vrid 2 priority 110
Note:Multiple virtual routers are often used in actual network applications.
1.5 Troubleshooting VRRP
As the configuration of VRRP is not very complicated, almost all the malfunctions can
be found through viewing the configuration and debugging information. Here are some
possible failures you might meet and the corresponding troubleshooting methods.
I. Symptom 1: Frequent prompts of configuration errors on the console
This indicates that incorrect VRRP packets have been received. It may be because of
the inconsistent configuration of another switch within the virtual router, or the attempts
of some devices to send out illegal VRRP packets. The first possible fault can be solved
through modifying the configuration. And as the second possibility is caused by the
malicious attempt of some devices, non-technical measures should be resorted to.
II. Symptom 2: More than one Master existing within the same virtual router
There are also 2 reasons. One is short time coexistence of many master switches,
which is normal and needs no manual intervention. Another is the long time
coexistence of many Master switches, which may be because switches in the virtual
router cannot receive VRRP packets from each other, or receive some illegal packets.
To solve such problems, an attempt should be made to ping the master switches. If
such an attempt fails, check the device connectivity. If they can be pinged, check the
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VRRP configuration. For the configuration of the same VRRP virtual router, complete
consistency for the number of virtual IP addresses, each virtual IP address, timer
duration and authentication type must be guaranteed.
III. Symptom 3: Frequent Master/Backup switchovers
Such problem occurs when the virtual router timer duration is too short. So the problem
can be solved through prolonging this duration or the preemption delay.