H3C S9500 Series Operating instructions

Brand: H3C

Model: S9500 Series

Type: Operating instructions

Operation Manual – VRRP

H3C S9500 Series Routing Switches Table of Contents

Table of Contents

Chapter 1 VRRP Configuration....................................................................................................1-1

1.1 Introduction to VRRP.........................................................................................................1-1

1.1.1 Overview .................................................................................................................1-1

1.1.2 VRRP Group Overview...........................................................................................1-2

1.1.3 VRRP Timers ..........................................................................................................1-5

1.1.4 Format of VRRP Packets........................................................................................1-5

1.1.5 Principles of VRRP..................................................................................................1-8

1.1.6 VRRP Interface Tracking ........................................................................................1-8

1.1.7 VRRP Application (Taking IPv4-Based VRRP for Example)..................................1-8

1.2 Configuring VRRP for IPv4..............................................................................................1-10

1.2.1 IPv4-Based VRRP Configuration Task List...........................................................1-10

1.2.2 Enabling Users to Ping Virtual IP Addresses of VRRP Groups............................1-11

1.2.3 Configuring the Association Between Virtual IP Address and MAC Address...............1-11

1.2.4 Creating VRRP Group and Configuring Virtual IP Address..................................1-12

1.2.5 Configuring Priority, Preemptive Mode and Interface Tracking for a VRRP Group............. 1-14

1.2.6 Configuring VRRP Packet Attributes ....................................................................1-15

1.2.7 Enabling the Trap Function of VRRP....................................................................1-16

1.2.8 Displaying and Maintaining VRRP for IPv4...........................................................1-17

1.3 Configuring VRRP for IPv6..............................................................................................1-17

1.3.1 IPv6-Based VRRP Configuration Task List...........................................................1-17

1.3.2 Enabling Users to Ping Virtual IPv6 Addresses of VRRP Groups........................1-18

1.3.3 Configuring the Association Between Virtual IPv6 Address and MAC Address............1-18

1.3.4 Creating VRRP Group and Configuring Virtual IPv6 Address..............................1-19

1.3.5 Configuring Priority, Preemption Mode and Interface Tracking for a VRRP Group.............1-20

1.3.6 Configuring VRRP Packet Attributes ....................................................................1-21

1.3.7 Displaying and Maintaining VRRP for IPv6...........................................................1-22

1.4 IPv4-Based VRRP Configuration Examples....................................................................1-22

1.4.1 Single VRRP Group Configuration Example.........................................................1-23

1.4.2 VRRP Interface Tracking Configuration Example.................................................1-25

1.4.3 Multiple VRRP Groups Configuration Example ....................................................1-29

1.5 IPv6-Based VRRP Configuration Examples....................................................................1-32

1.5.1 Single VRRP Group Configuration Example.........................................................1-33

1.5.2 VRRP Interface Tracking Configuration Example.................................................1-36

1.5.3 Multiple VRRP Groups Configuration Example ....................................................1-39

1.6 Troubleshooting VRRP....................................................................................................1-42

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Chapter 1 VRRP Configuration

When configuring VRRP, go to these sections for information you are interested in:

z Introduction to VRRP

z Configuring VRRP for IPv4

z Configuring VRRP for IPv6

z IPv4-Based VRRP Configuration Examples

z IPv6-Based VRRP Configuration Examples

z Troubleshooting VRRP

 Note:

z The term router and the icon router in this document refer to a router in a generic

sense or an S9500 series routing switch running routing protocols.

z At present, the interfaces that VRRP involves can only be VLAN interfaces for

S9500 series switches.

1.1 Introduction to VRRP

This section covers these topics:

z Overview

z VRRP Group Overview

z VRRP Timers

z Format of VRRP Packets

z Principles of VRRP

z VRRP Interface Tracking

z VRRP Application (Taking IPv4-Based VRRP for Example)

1.1.1 Overview

As shown in Figure 1-1, you can configure a default route with the gateway as the next

hop for every host on a network segment, allowing all packets destined to other network

segments to be sent over the default route to the gateway and then be forwarded by the

gateway. This enables hosts on a network segment to communicate with external

networks. However, when the gateway fails, all the hosts using the gateway as the

default next-hop router are isolated from the external network.

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Gateway

Network

Host A

Host B

Host C

Figure 1-1 Common LAN networking

Apparently, this approach to enabling hosts on a network to communicate with external

networks is easy to configure but it imposes a very high requirement of performance

stability on the device acting as the gateway. A common way to improve system

reliability is to use more egress gateways, introducing the problem of routing among the

multiple egresses.

Virtual Router Redundancy Protocol (VRRP) was designed to address this problem.

VRRP can add routers that can act as network gateways to a VRRP group, forming a

virtual router. Routers in the VRRP group elect a master through the VRRP election

mechanism to take the responsibility of a gateway, and hosts on a LAN only need to

configure the virtual router as their default network gateway.

VRRP is an error-tolerant protocol, which improves the network reliability and simplifies

configurations on hosts. Deploying VRRP on multicast and broadcast LANs such as

Ethernet, you can ensure that the system can still provide highly reliable default links

without changing configurations (such as dynamic routing protocols, route discovery

protocols) when a device fails and prevent network interruption due to a single link

failure.

There are two VRRP versions: VRRPv2 and VRRPv3. VRRPv2 is based on IPv4, while

VRRPv3 is based on IPv6. The two versions implement the same functions but provide

different commands.

1.1.2 VRRP Group Overview

This section introduces some concepts used throughout this document:

z VRRP group

z VRRP priority

z Working mode

z Authentication mode

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I. VRRP group

VRRP combines a group of routers on a LAN (including a master and multiple backups)

into a virtual router called VRRP group.

The VRRP group has the following features:

z A virtual router has an IP address. A host on the LAN only needs to know the IP

address of the virtual router and uses the IP address as the next hop of the default

route.

z Every host on the LAN communicates with external networks through the virtual

router.

z Routers in the VRRP group elect the gateway according to their priorities. Once

the master acting as the gateway fails, the other routers in the VRRP group elect a

new gateway to undertake the responsibility of the failed router, thus ensuring that

the hosts in the network segment can communicate with the external networks

uninterruptedly.

Host A

Host B

Host C

Router A

Router B

Router C

Virtual router

Network

Figure 1-2 Network diagram for VRRP

As shown in

Figure 1-2, Router A, Router B, and Router C form a virtual router, which

has its own IP address. Hosts on the Ethernet use the virtual router as the default

gateway.

The router with the highest priority of the three routers is elected as the master to act as

the gateway, and the other two are backups.

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Caution:

z The IP address of the virtual router can be either an unused IP address on the

segment where the VRRP group resides or the IP address of an interface on a

router in the VRRP group. In the latter case, the router is called the IP address

owner.

z In a VRRP group, there can only be one IP address owner.

II. VRRP priority

VRRP determines the role (master or backup) of each router in the VRRP group by

priority. A router with a higher priority has more opportunity to become the master.

VRRP priority that can be configured by users is in the range of 1 to 254. A bigger

number means a higher priority. Priority 0 is reserved for special uses and priority 255

for the IP address owner. When a router acts as the IP address owner, its priority

remains 255. That is, if there is an IP address owner in a VRRP group, it acts as the

master as long as it works properly.

III. Working mode

A router in a VRRP group can work in one of the following two modes:

z Non-preemptive mode

Once a router in the VRRP group becomes the master, it stays as the master as long as

it operates normally, even if a backup is assigned a higher priority later.

z Preemptive mode

Once a backup finds its priority higher than that of the router acting as the master, it

sends VRRP advertisements to start a new master election in the VRRP group and

becomes the master. Accordingly, the original master becomes a backup.

IV. Authentication mode

On a secure network, you can configure the routers not to perform authentication. In

this case, neither the routers sending VRRP packets nor the routers receiving the

VRRP packets perform authentication.

On a network where potential threats are present, you can configure VRRP

authentication to enhance the network security.

VRRP provides two authentication modes:

z simple: Simple text authentication

A router sending a packet fills the authentication key into the packet, and the router

receiving the packet compares its local authentication key with that of the received

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packet. If the two authentication keys are the same, the received VRRP packet is

considered real and valid; otherwise, the received packet is considered an invalid one.

z md5: MD5 authentication

The router encrypts a packet to be sent using the authentication key and MD5 algorithm

and saves the encrypted packet in the authentication header. The router receiving the

packet uses the authentication key to decrypt the packet and checks whether the

packet is valid.

1.1.3 VRRP Timers

VRRP timers include VRRP advertisement interval timer and VRRP preemption delay

timer.

I. VRRP advertisement interval timer

The master in a VRRP group sends VRRP advertisements periodically to inform the

other routers in the VRRP group that it operates properly.

You can adjust the interval of sending VRRP advertisements by setting the VRRP

advertisement interval timer. If a backup receives no advertisements in a period three

times the interval, the backup regards itself as the master and sends VRRP

advertisements to start a new master election.

II. VRRP preemption delay timer

In an unstable network, a backup may fail to receive the packets from the master due to

network congestion, thus causing the members in the group to change their states

frequently. This problem can be addressed through setting the VRRP preemption delay

timer.

With the VRRP preemption delay timer set, if a backup receives no advertisement in a

period three times the advertisement interval and then in preemption delay, it considers

that the master fails. In this case, it regards itself as the master and sends VRRP

advertisements to start a new master election in a VRRP group.

1.1.4 Format of VRRP Packets

VRRP uses multicast packets. The router acting as the master sends VRRP packets

periodically to declare its existence. VRRP packets are also used for checking the

parameters of the virtual router and electing the master.

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I. IPv4-based VRRP packet format

Figure 1-3 IPv4-based VRRP packet format

As shown in

Figure 1-3, an IPv4-based VRRP packet consists of the following fields:

z Version: Version number of the protocol, 2 for VRRPv2.

z Type: Type of the VRRP packet. Only one VRRP packet type is present, that is,

VRRP advertisement, which is represented by 1.

z Virtual Rtr ID (VRID): Serial number of the virtual router, that is, serial number of

the VRRP group. It ranges from 1 to 255.

z Priority: Priority of the router in the VRRP group, in the range 0 to 255. A greater

value represents a higher priority.

z Count IP Addrs: Number of virtual IP addresses for the VRRP group. A VRRP

group can have multiple virtual IP addresses.

z Auth Type: Authentication type. 0 means no authentication, 1 means simple

authentication, and 2 means MD5 authentication.

z Adver Int: Interval for sending advertisement packets, in seconds. The default is 1.

z Checksum: 16-bit checksum for validating the data in VRRP packets.

z IP Address: Virtual IP address entry of the VRRP group. The allowed number is

given by the Count IP Addrs field.

z Authentication Data: Authentication key. Currently, this field is used only for simple

authentication and is 0 for any other authentication modes.

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II. IPv6-based VRRP packet format

Version Type Virtual Rtr ID Priority Count IPv6 Addrs

Auth Type Adver Int Checksum

IPv6 address 1

Authentication data 1

Authentication data 2

IPv6 address n

0 7 15 23 313

Figure 1-4 IPv6-based VRRP packet format

As shown in

Figure 1-4, an IPv6-based VRRP packet consists of the following fields:

z Version: Version number of the protocol, 3 for VRRPv3.

z Type: Type of the VRRP packet. Only one VRRP packet type is present, that is,

VRRP advertisement, which is represented by 1.

z Virtual Rtr ID (VRID): Serial number of the virtual router, that is, serial number of

the VRRP group. It ranges from 1 to 255.

z Priority: Priority of the router in the VRRP group, in the range 0 to 255. A greater

value represents a higher priority.

z Count IPv6 Addrs: Number of virtual IPv6 addresses for the VRRP group. A VRRP

group can have multiple virtual IPv6 addresses.

z Auth Type: Authentication type. 0 means no authentication, 1 means simple

authentication. VRRPv3 does not support MD5 authentication.

z Adver Int: Interval for sending advertisement packets, in centiseconds. The default

is 100.

z Checksum: 16-bit checksum for validating the data in VRRPv3 packets.

z IPv6 Address: Virtual IPv6 address entry of the VRRP group. The allowed number

is given by the Count IPv6 Addrs field.

z Authentication Data: Authentication key. Currently, this field is used only for simple

authentication and is 0 for any other authentication modes.

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1.1.5 Principles of VRRP

1) With VRRP enabled, the routers determine their respective roles in the VRRP

group by priority. The router with the highest priority becomes the master, while

the others are the backups. The master sends VRRP advertisement packets

periodically to notify the backups that it is working properly, and each of the

backups starts a timer to wait for advertisement packets from the master.

2) In preemptive mode, when a backup receives a VRRP advertisement, it compares

the priority in the packet with that of its own. If its priority is lower, it remains a

backup; otherwise, it becomes the master.

3) In non-preemptive mode, the router in the VRRP group remains as a master or

backup as long as the master does not fail. The backup will no become the master

even if the former is configured with a higher priority.

4) If the timer of a backup expires but the backup still does not receive any VRRP

advertisement packet, it considers that the master fails. In this case, the backup

considers itself as the master and sends VRRP advertisements to start the

election process to elect a new master for forwarding packets.

1.1.6 VRRP Interface Tracking

The VRRP interface tracking function expands the backup functionality of VRRP. It

provides backup not only when the interface to which a VRRP group is assigned fails

but also when other interfaces on the router become unavailable. When a monitored

interface goes down, the priority of the router owning the interface is automatically

decreased by a specified value, allowing a higher priority router in the VRRP group to

become the master.

1.1.7 VRRP Application (Taking IPv4-Based VRRP for Example)

I. Master/backup

In master/backup mode, only one router, the master, provides services. When the

master fails, a new master is elected from the original backups. This mode requires

only one VRRP group, in which each router holds different priorities and the one with

the highest priority becomes the master, as shown in

Figure 1-5.

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Figure 1-5 VRRP in master/backup mode

At the beginning, Router A is the master and therefore can forward packets to external

networks, while Router B and Router C are backups and are thus in the state of

listening. If Router A fails, Router B and Router C will elect for the new master. The new

master takes over the forwarding task to provide services to hosts on the LAN.

II. Load balancing

You can create more than one VRRP group on an interface of a router, allowing the

router to be the master of one VRRP group but a backup of another at the same time.

In load balancing mode, multiple routers provide services at the same time. This mode

requires two or more VRRP groups, each of which includes a master and one or more

backups. The masters of the VRRP groups can be assumed by different routers, as

shown in

Figure 1-6.

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Host A

Host B

Host C

Router A

Backup

Router B

Backup

Router C

Master

Virtual router 2

Virtual router 3Virtual router 1

Master

Backup

Backup Backup

Master

Backup

Network

Figure 1-6 VRRP in load balancing mode

A router can be in multiple VRRP groups and hold a different priority in different group.

Figure 1-6, three VRRP groups are present:

z VRRP group 1: Router A is the master; Router B and Router C are the backups.

z VRRP group 2: Router B is the master; Router A and Router C are the backups.

z VRRP group 3: Router C is the master; Router A and Router B are the backups.

For load balancing among Router A, Router B, and Router C, hosts on the LAN need to

be configured to use VRRP group 1, 2, and 3 as the default gateways respectively.

When configuring VRRP priorities, ensure that each router holds such a priority in each

VRRP group that it will take the expected role in the group.

1.2 Configuring VRRP for IPv4

1.2.1 IPv4-Based VRRP Configuration Task List

Complete these tasks to configure VRRP for IPv4:

Task Remarks

Enabling Users to Ping Virtual IP Addresses of VRRP Groups Optional

Configuring the Association Between Virtual IP Address and

MAC Address

Optional

Creating VRRP Group and Configuring Virtual IP Address Required

Configuring Priority, Preemptive Mode and Interface Tracking Optional

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Task Remarks

Configuring VRRP Packet Attributes Optional

Enabling the Trap Function of VRRP Optional

Caution:

VRRP is not supported on the VLAN interfaces of Super VLAN. Do not configure VRRP

on this type of interfaces.

1.2.2 Enabling Users to Ping Virtual IP Addresses of VRRP Groups

You can configure that the master of a VRRP group responds to the received ICMP

echo requests, that is, the virtual IP address of the VRRP group can be successfully

pinged.

Follow these steps to enable a user to successfully ping the virtual IP addresses of

VRRP groups:

To do… Use the command… Remarks

Enter system view

system-view

—

Enable users to ping

virtual IP address of the

VRRP group

vrrp ping-enable

Optional

Enabled by default.

Caution:

Configure this function before creating a VRRP group. Otherwise, your configuration

will fail.

1.2.3 Configuring the Association Between Virtual IP Address and MAC Address

After the virtual IP address of a VRRP group is associated with a MAC address, the

master takes the configured MAC address as the source MAC address of the packets

to be sent, so that the hosts in the internal network can learn the association between

the IP address and the MAC address and thus forward the packets to be forwarded to

the other network segments to the master properly.

There are two types of association between virtual IP address and MAC address:

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z Virtual IP address is associated with virtual router MAC address

By default, a MAC address is created for a VRRP group after the VRRP group is

created, and the virtual IP address is associated with the virtual MAC address. With

such association adopted, the hosts in the internal network need not update the

association between IP address and MAC address when the master changes.

z Virtual IP address is associated with real MAC address of the interface

When an IP address owner exists in a VRRP group, if you associate the virtual IP

address with the virtual MAC address, two MAC addresses are associated with an IP

address. In this case, you can associate the virtual IP address of the VRRP group with

the real MAC address, so that the packets from a host are forwarded to the IP address

owner according the real MAC address.

Follow these steps to configure the association between virtual IP address and MAC

address:

To do… Use the command… Remarks

Enter system view

system-view

—

Configure the association

between MAC address

and virtual IP address

vrrp method { real-mac |

virtual-mac }

Optional

The virtual MAC address

is associated with the

virtual IP address by

default.

Caution:

You need to configure the association before creating a VRRP group. After a VRRP

group is created, you cannot modify the association between the virtual IP address and

the MAC address.

1.2.4 Creating VRRP Group and Configuring Virtual IP Address

You need to configure a virtual IP address for a VRRP group when creating the VRRP

group. If the interface connects to multiple sub-networks, you can configure multiple

virtual IP addresses for the VRRP group to realize router backup on different

sub-networks. A VRRP group is created automatically when you specify the first virtual

IP address for the VRRP group. If you specify a virtual IP address for the VRRP group

later, the virtual IP address is only added to the virtual IP address list of the VRRP

group.

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Caution:

It is not recommended to create VRRP groups on the VLAN interface of a super VLAN.

Otherwise, network performance may be affected.

I. Configuration prerequisites

Before creating VRRP group and configuring virtual IP address, you should first

configure the IP address of the interface and ensure that the virtual IP address to be

configured is in the same network segment as the IP address of the interface.

II. Configuration procedure

Follow these steps to create VRRP group and configure virtual IP address:

To do… Use the command… Remarks

Enter system view

system-view

—

Enter VLAN interface view

interface interface-type

interface-number

—

Create a VRRP group and

configure virtual IP

address of the VRRP

group

vrrp vrid virtual-router-id

virtual-ip virtual-address

Required

Standup group is not

created by default.

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Caution:

z For S9500 series switches, the maximum number of VRRPv2 VRRP groups on an

interface is 16, the maximum number of virtual IP addresses in a VRRP group is 16

and the maximum number of VRRP groups on a switch is 96.

z A VRRP group is removed after you remove all the virtual IP addresses in it. In

addition, configurations on that VRRP group no longer take effect.

z Removal of the VRRP group on the IP address owner will cause IP address collision.

In such a case, it is recommended to modify the IP address of the interface on the IP

address owner to resolve the collision.

z The virtual IP address of the VRRP group cannot be 0.0.0.0, 255.255.255.255,

loopback address, non A/B/C address and other illegal IP addresses such as

0.0.0.1.

z Only when the configured virtual IP address and the interface IP address belong to

the same segment and are legal host addresses can the VRRP group operate

normally. If the configured virtual IP address and the interface IP address do not

belong to the same network segment, or the configured IP address is the network

address or network broadcast address of the network segment to which the

interface IP address belongs, the state of the VRRP group is always initialize,

though you can perform the configuration successfully, that is, VRRP does not take

effect in this case.

1.2.5 Configuring Priority, Preemptive Mode and Interface Tracking for a VRRP

Group

I. Configuration prerequisites

Before you configure these features, you should first create a VRRP group on the

interface and configure virtual IP address for it.

II. Configuration procedure

By configuring priority, preemption mode and interface tracking for a VRRP group, you

can decide which switch in the VRRP group serves as the Master.

Follow these steps to configure priority, preemption mode and interface tracking for a

VRRP group:

To do… Use the command… Remarks

Enter system view

system-view

—

Enter VLAN interface view

interface interface-type

interface-number

—

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To do… Use the command… Remarks

Configure switch priority

in the VRRP group

vrrp vrid virtual-router-id

priority priority-value

Optional

100 by default.

Configure the switch in

the VRRP group to work

in preemption mode and

configure preemption

delay

vrrp vrid virtual-router-id

preempt-mode [ timer

delay delay-value ]

Optional

The switch in the VRRP

group works in

preemption mode and the

preemption delay is 0

seconds by default.

Configure the interface to

be tracked

vrrp vrid virtual-router-id

track interface

interface-type

interface-number

[ reduced

priority-reduced ]

Optional

No interface is being

tracked by default.

Caution:

z The running priority of an IP address owner is always 255 and you do not need to

configure it. An IP address owner always works in the preemptive mode.

z Interface tracking is not configurable on an IP address owner.

z Tracked interfaces can only be VLAN interfaces.

z The priority of a device is restored if the state of the interface under tracking

changes from down to up.

1.2.6 Configuring VRRP Packet Attributes

I. Configuration prerequisites

Before configuring the relevant attributes of VRRP packets, you should first create the

VRRP group and configure the virtual IP address.

II. Configuration procedure

Follow these steps to configure VRRP packet attributes:

To do... Use the command... Remarks

Enter system view

system-view

—

Enter VLAN interface view

interface interface-type

interface-number

—

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To do... Use the command... Remarks

Configure the

authentication mode and

authentication key when

the VRRP groups send

and receive VRRP

packets

vrrp vrid virtual-router-id

authentication-mode

{ md5 | simple } key

Optional

Authentication is not

performed by default

Configure the time interval

for the Master in the

VRRP group to send

VRRP advertisement

vrrp vrid virtual-router-id

timer advertise

adver-interval

Optional

1 second by default

Disable TTL check on

VRRP packets

vrrp un-check ttl

Optional

Enabled by default

 Note:

z You may configure different authentication modes and authentication keys for the

VRRP groups on an interface. However, the members of the same VRRP group

must use the same authentication mode and authentication key.

z Factors like excessive traffic or different timer setting on switches can cause the

Backup timer to time-out abnormally and trigger a change of the state. To solve this

problem, you can prolong the time interval to send VRRP packets and configure a

preemption delay.

1.2.7 Enabling the Trap Function of VRRP

After the trap function is enabled for a VRRP module, the VRRP module will generate

traps with severity level errors to report its key events. The generated traps will be sent

to the information center of the device, where you can configure whether to output the

trap information and the output destination. For information center configurations, refer

to Information Center Configuration in the System Volume.

Follow these steps to enable the trap function of VRRP:

To do… Use the command… Remarks

Enter system view

system-view

—

Enable the trap function of

VRRP

snmp-agent trap enable

vrrp [ authfailure |

newmaster ]

Optional

Enabled by default.

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 Note:

For detailed description on the snmp-agent trap enable vrrp command, refer to

command snmp-agent trap enable in SNMP Commands in the System Volume.

1.2.8 Displaying and Maintaining VRRP for IPv4

To do… Use the command… Remarks

Display VRRP

status

display vrrp [ verbose ] [ interface

interface-type interface-number [ vrid

virtual-router-id ] ]

Available in any

view

Display VRRP

statistics

display vrrp statistics [ interface

interface-type interface-number [ vrid

virtual-router-id ] ]

Available in any

view

Remove VRRP

statistics

reset vrrp statistics [ interface

interface-type interface-number [ vrid

virtual-router-id ] ]

Available in user

view

1.3 Configuring VRRP for IPv6

1.3.1 IPv6-Based VRRP Configuration Task List

Complete these tasks to configure VRRP for IPv6:

Task Remarks

Enabling Users to Ping Virtual IPv6 Addresses Optional

Configuring the Association Between Virtual IPv6 Address

and MAC Address

Optional

Creating VRRP Group and Configuring Virtual IPv6 Address Required

Configuring Priority, Preemption Mode and Interface Tracking Optional

Configuring VRRP Packet Attributes Optional

Caution:

VRRP is not supported on the VLAN interfaces of Super VLAN. Do not configure VRRP

on this type of interfaces.

Operation Manual – VRRP

H3C S9500 Series Routing Switches Chapter 1 VRRP Configuration

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1.3.2 Enabling Users to Ping Virtual IPv6 Addresses of VRRP Groups

You can configure whether the master responds to the received ICMPv6 echo requests,

that is, whether the virtual IPv6 address of a VRRP group can be successfully pinged.

Follow these steps to enable a user to successfully ping the virtual IPv6 addresses of

VRRP groups:

To do… Use the command… Remarks

Enter system view

system-view

—

Enable a user to ping

virtual IPv6 address of the

VRRP group

vrrp ipv6 ping-enable

Optional

Enabled by default

Caution:

You should configure this function before creating a VRRP group. Otherwise, you

cannot ping the virtual IPv6 addresses of VRRP groups.

1.3.3 Configuring the Association Between Virtual IPv6 Address and MAC

Address

After the virtual IPv6 address of a VRRP group is associated with the MAC address, the

master takes the configured MAC address as the source MAC address of the packets

to be sent, so that the hosts in the internal network can learn the association between

the IPv6 address and the MAC address and thus forward the packets to be forwarded

to the other network segments to the master properly.

There are two types of association between virtual IPv6 address and MAC address:

z Virtual IPv6 address is associated with virtual router MAC address

By default, a MAC address is created for a VRRP group after the VRRP group is

created, and the virtual IPv6 address is associated with the virtual MAC address. With

such association adopted, the hosts in the internal network need not update the

association between IPv6 address and MAC address when the master changes.

z Virtual IPv6 address is associated with real MAC address of the interface

When an IP address owner exists in a VRRP group, if you associate the virtual IPv6

address with the virtual MAC address, two MAC addresses are associated with an IPv6

address. In this case, you can associate the virtual IPv6 address of the VRRP group

with the real MAC address, so that the packets from a host are forwarded to the IP

address owner according the real MAC address.

Operation Manual – VRRP

H3C S9500 Series Routing Switches Chapter 1 VRRP Configuration

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Follow these steps to configure the association between virtual IPv6 address and MAC

address:

To do… Use the command… Remarks

Enter system view

system-view

—

Configure the association

between virtual IPv6

address and MAC

address

vrrp ipv6 method

{ real-mac | virtual-mac }

Optional

The virtual MAC address

of the VRRP group is

associated with the virtual

IPv6 address by default.

Caution:

You need to configure the association before creating a VRRP group. After a VRRP

group is created, you cannot modify the association between the virtual IP address and

the MAC address.

1.3.4 Creating VRRP Group and Configuring Virtual IPv6 Address

You need to configure a virtual IPv6 address for a VRRP group when creating the

VRRP group. You can configure multiple virtual IPv6 addresses for a VRRP group.

A VRRP group is created automatically when you specify the first virtual IPv6 address

for the VRRP group. If you specify a virtual IPv6 address for the VRRP group later, the

virtual IPv6 address is only added to the virtual IPv6 address list of the VRRP group.

Caution:

It is not recommended to create VRRP groups on the VLAN interface of a super VLAN.

Otherwise, network performance may be affected.

I. Configuration prerequisites

Before creating VRRP group and configuring virtual IPv6 address, you should first

configure the IPv6 address of the interface and ensure that the virtual IPv6 address to

be configured is in the same network segment as the IPv6 address of the interface.

II. Configuration procedure

Follow these steps to create VRRP group and configure its virtual IPv6 address:

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H3C S9500 Series Operating instructions

H3C S9500 Series Operating instructions

H3C S9500 Series Operating instructions

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