Table of Contents

1 IRF Fabric Configuration· 1-1

Introduction to IRF· 1-1

Establishment of an IRF Fabric· 1-1

How IRF Works· 1-5

IRF Fabric Configuration· 1-6

IRF Fabric Configuration Task List 1-6

Specifying the Fabric Port of a Switch· 1-7

Specifying the VLAN Used to Form an IRF Fabric· 1-8

Setting a Unit ID for a Switch· 1-9

Assigning a Unit Name to a Switch· 1-10

Assigning an IRF Fabric Name to a Switch· 1-10

Setting the IRF Fabric Authentication Mode· 1-11

Configuring IRF Automatic Fabric for a Switch· 1-11

Displaying and Maintaining IRF Fabric· 1-12

IRF Fabric Configuration Example· 1-12

Network Requirements· 1-12

Network Diagram·· 1-13

Configuration Procedure· 1-13

 

 

 

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

l          Introduction to IRF

l          IRF Fabric Configuration

l          Displaying and Maintaining IRF Fabric

l          IRF Fabric Configuration Example

Introduction to IRF

Intelligent Resilient Framework (IRF), a feature particular to H3C S3600 series switches, is a new technology for building the core of a network. This feature allows you to build an IRF fabric by interconnecting several S3600 series switches to provide more ports for network devices and improve the reliability of your network.

Establishment of an IRF Fabric

Topology and connections of an IRF fabric

An IRF fabric typically has a ring topology structure. As shown in Figure 1-1, each switch has two ports connected with two other switches in the fabric. These two ports are called fabric ports in general, a left port and a right port respectively; the other ports, which are available for connections with users or devices outside the fabric, are called user ports.

Figure 1-1 A schematic diagram of an IRF fabric

 

A correctly built IRF fabric features the following:

l          Multiple S3600 series switches are interconnected through their fabric ports.

l          Given a switch, its left port is connected to the right port of another switch, and its right port is connected to the left port of a third one.

Figure 1-2 Port connection mode for S3600 series ring topology IRF fabric Port connection mode for S3600 series ring topology IRF fabric is shown in Figure 1-2.

 

IRF fabric also supports bus topology, which has the same requirements as the ring topology. The difference is that in a bus topology structure, the units at both ends of the bus have only one fabric port connected, as shown in Figure 1-3.

Figure 1-3 IRF fabric bus topology

 

Fabric ports

On an S3600 series Ethernet switch, only four GigabitEthernet ports can be configured as fabric ports. If not used for fabric connection, these four ports can be used as general data ports. The four ports fall into two groups according to their port numbers:

l          GigabitEthernet 1/1/1 and GigabitEthernet 1/1/2 form the first group.

l          GigabitEthernet 1/1/3 and GigabitEthernet 1/1/4 form the second group.

Only one group of ports can be configured as fabric ports at a time. Given a group, either GigabitEthernet 1/1/1 or GigabitEthernet 1/1/3 can be configured as the left fabric port, and either GigabitEthernet 1/1/2 or GigabitEthernet 1/1/4 can be configured as the right fabric port.

Once you configure a port as a fabric port, the group that comprises this fabric port becomes the fabric port group, and you cannot configure a port in the other group as a fabric port. For example, once you configure GigabitEthernet 1/1/1 as a fabric port, this port automatically becomes the left port and the first group becomes the fabric port group.

 

 

FTM

As the basis of the IRF function, the Fabric Topology Management (FTM) program manages and maintains the entire topology of a fabric.

With fabric ports configured, the FTM program releases information of the device through the fabric ports. The device information includes Unit ID, CPU MAC, device type ID, fabric port information, and all fabric configuration information. The device information is released in the discovery packet (DISC).

After receiving the packet, the peer device will analyze the packet. A device can form a fabric with the peer or join a fabric only when the following conditions are met.

l          The number of the existing devices in the fabric does not reach the maximum number of devices allowed by the fabric (up to eight devices can form a fabric).

l          The fabric name of the device and the existing devices in the fabric are the same.

l          The software version of the device is the same as that of the existing devices in the fabric.

l          The device passes the security authentication if security authentication is enabled on the device or in the fabric, that is, the same authentication mode and password are configured on the device and the existing devices in the fabric.

 

 

IRF fabric detection

Forming a fabric requires a high consistency of connection modes between the devices and device information. Without all the requirements for forming a fabric being met, a fabric cannot be formed.

The FTM program detects the necessary conditions for forming a fabric one by one and displays the detection results. You can use the display ftm information command to view the detection information for the fabric, checking the running status of the fabric or analyzing the problems. Table 1-1 lists the status and solution of the problems.

Table 1-1   Status and solution

Status	Analysis		Solution
normal	—		These three kinds of information do not mean a device or a fabric operates improperly. No measure is needed for any of them.
temporary
redundance port
connection error	Indicates three kinds of port matching errors may occur.	Two fabric ports of the same device (that is, the right port and the left port) are connected.	Pull out one end of the cable and connect it to a fabric port of another switch.
		The left and right fabric ports of the devices are not connected in a crossed way.	Connect the left and right ports of two devices in a crossed way.
		A fabric port of the local switch is connected to a non-fabric port, or is connected to a fabric port that does not have fabric port function enabled.	Check the types of the two interconnected ports on two sides. Make sure a fabric port is only connected to ports of the same type and the fabric ports on both sides are enabled with the fabric port function.
reached max units	The maximum number of units allowed by the current fabric is reached. You will fail to add new devices to the fabric in this case.		Remove the new device or existing devices in the fabric.
different system name	The fabric name of the device directly connected to the switch and the existing fabric name of the fabric are not the same.		Modify the fabric name of the new device to be that of the fabric.
different product version	The software version of the directly connected device and that of the current device are not the same.		Update the software version to make sure the software version of the new device is the same as that of the fabric.
auth failure	The IRF fabric authentication modes configured for the local device and that of the fabric are not the same, or the password configured does not match.		Configure the IRF fabric authentication modes and the passwords for the local device and the fabric as the same.

 

IRF automatic fabric

If the software version and fabric name of the candidate switch are inconsistent with those of the device in the IRF fabric, the local device cannot be added to the fabric. In this case, you have to manually download and load the software, and then restart the device, or manually change the fabric name to add the device to the fabric. H3C S3600 series switches provide the IRF automatic fabric function, which enables a candidate switch to automatically download the software and change the fabric name in case that the software version and fabric name of the candidate device and that of the device in the fabric are different, thus reducing the manual maintenance workload.

With IRF automatic fabric enabled, if inconsistency in software version or fabric name occurs when a switch is added to a fabric, the system automatically performs the following operations:

l          If the software version of the local device is inconsistent with that of the device in the fabric, the system automatically initiates a download request to the device with the smallest unit ID in the fabric and downloads the software used by the device in the current fabric to the local device. Then the device will automatically restart and be added to the fabric.

l          If the fabric name of the local device is inconsistent with that of the device in the fabric, the system automatically ignores the inconsistency check of the fabric name and adds the device to the fabric. Then the system automatically synchronizes the configurations to the device with the smallest unit ID and changes the fabric name.

With the above operations completed, the device can be added to the fabric and work normally.

 

 

How IRF Works

When a fabric is established, the devices determine their respective roles in the fabric by comparing their CPU MAC addresses. The device with the lowest CPU MAC address is elected as the master and the other devices are slaves.

After the election, the fabric can operate normally. The following three functions of IRF can provide simple configuration mode, enhanced network performance and perfect redundancy backup mechanism for users.

 

 

DDM

DDM is a new device management mode provided by IRF. In normal cases, a fabric can be considered as a single device. You can manage the entire fabric by logging onto any device in the fabric with different logging modes. The devices in the fabric synchronize their configurations by exchanging packets, thus ensuring stability of the fabric.

FTM program uses Unit ID, or device ID to distinguish between the devices in a fabric when you manage them. On initialization of the IRF function, each device considers its Unit ID as 1 and after a fabric connection is established, the FTM program automatically re-numbers the devices or you can manually configure the Unit ID of them.

The master in a fabric collects the newest configurations of the user and the slaves periodically synchronize the configurations from the master. In this way, the entire fabric can operate with the same configurations.

DRR

DRR is used to implement redundancy routing backup. The devices in a fabric run their independent routing protocols and maintain their own routing tables. Unlike a common layer 3 switch, a fabric member does not generate a layer 3 forwarding table to forward packets; instead, it uploads the routing table to the master, which generates a forwarding table used by the entire fabric by integrating the routing tables of all the devices. Then each slave synchronizes this forwarding table from the master and takes it as the basis for layer 3 forwarding.

In this way, the forwarding table entries of each device in the fabric can be consistent. Even if the master fails, other devices can use the forwarding table synchronized from the master to perform layer 3 forwarding, thus ensuring the accuracy of forwarding path. After re-electing the master, the fabric will restart routing update.

DLA

As a new link aggregation mode, DLA can improve fault tolerance and redundancy backup of user networks.

Link aggregation enables you to configure ports on the same device as an aggregation port group, avoiding network interruptions resulted from single port failure. Based on link aggregation, DLA provides a more reliable solution, with which you can select ports on different devices to form an aggregation port group. In this way, single port failure can be avoided and network reliability can be greatly improved, because the fabric can communicate with the destination network through ports on other devices in case a single device fails.

IRF Fabric Configuration

IRF Fabric Configuration Task List

Complete the following tasks to configure IRF fabric:

Task	Remarks
Specifying the Fabric Port of a Switch	Required
Specifying the VLAN Used to Form an IRF Fabric	Optional
Setting a Unit ID for a Switch	Optional
Assigning a Unit Name to a Switch	Optional
Assigning an IRF Fabric Name to a Switch	Optional
Setting the IRF Fabric Authentication Mode	Optional
Configuring IRF Automatic Fabric for a Switch	Optional

 

Specifying the Fabric Port of a Switch

You can specify the fabric port of a switch in either system view or Ethernet interface view.

Configurations in system view

Follow these steps to specify a fabric port:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Specify the fabric port of a switch	fabric-port interface-type interface-number enable	Required Not specified by default

 

Configurations in Ethernet interface view

Follow these steps to specify a fabric port:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter Ethernet interface view	interface interface-type interface-number	—
Specify the current port as the fabric port of a switch	port link-type irf-fabric	Required No port is specified as the fabric port by default.

 

 

Specifying the VLAN Used to Form an IRF Fabric

When the devices in an IRF fabric are transmitting IRF data, to avoid it being sent to other non fabric ports, the data should be transmitted in a specified VLAN. You can specify the VLAN used to transmit IRF data.

Follow these steps to specify the VLAN used to form an IRF fabric:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Specify the VLAN used to form an IRF fabric	ftm fabric-vlan vlan-id	Required By default, the VLAN used to form the IRF fabric is VLAN 4093

 

 

Setting a Unit ID for a Switch

On the switches that support automatic numbering, FTM will automatically number the switches to constitute an IRF fabric by default, so that each switch has a unique unit ID in the fabric. You can use the command in the following table to set unit IDs for switches. Make sure to set different unit IDs for different switches in an IRF fabric. Otherwise, FTM will automatically number the switches with the same unit ID.

Follow these steps to set a unit ID for a switch:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Set a unit ID for the switch	change self-unit to { unit-id | auto-numbering }	Optional By default, the unit ID of a switch that belongs to no IRF fabric is 1. The unit ID of a switch belonging to an IRF fabric is assigned by FTM. Unit ID ranges from 1 to 8.

 

 

After an IRF fabric is established, you can use the following command to change the unit IDs of the switches in the IRF fabric.

Follow these steps to set a unit ID to a new value:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Set a unit ID to a new value	change unit-id unit-id1 to { unit-id2 | auto-numbering }	Optional

 

 

After you change the unit ID of switches, the following operations are performed.

l          If the modified unit ID does not exist in the IRF fabric, the system sets its priority to 5 and saves it in the unit Flash memory.

l          If the modified unit ID is an existing one, the system prompts you to confirm if you really want to change the unit ID. If you choose to change it, the existing unit ID is replaced and the priority is set to 5. Then you can use the fabric save-unit-id command to save the modified unit ID into the unit Flash memory and clear the information about the existing one.

l          If auto-numbering is selected, the system sets the unit priority to 10. You can use the fabric save-unit-id command to save the modified unit ID into the unit Flash memory and clear the information about the existing one.

 

 

After the configuration of numbering, you can use the following command in the table to save the local unit ID in the unit Flash memory. When you restart the switch, it can load the unit ID configuration automatically.

Follow these steps to save the unit ID of each unit in the IRF fabric:

To do…	Use the command…	Remarks
Save the unit ID of each unit in the IRF fabric	fabric save-unit-id	Optional

 

Assigning a Unit Name to a Switch

Follow these steps to assign a unit name to a switch:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Assign a unit name to a switch	set unit unit-id name unit-name	Required

 

Assigning an IRF Fabric Name to a Switch

Only the switches with the same IRF fabric name can form an IRF fabric.

Follow these steps to assign a fabric name to a switch:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Assign a fabric name to the switch	sysname sysname	Optional By default, the IRF fabric name is H3C.

 

Setting the IRF Fabric Authentication Mode

Only the switches with the same IRF fabric authentication mode can form an IRF fabric.

Follow these steps to set the IRF fabric authentication mode for a switch:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Set the IRF fabric authentication mode for the switch	irf-fabric authentication-mode { simple password | md5 key }	Optional By default, no authentication mode is set on a switch.

 

 

Configuring IRF Automatic Fabric for a Switch

Configuration prerequisites

l          Make sure that the Flash of the newly added device has enough space to download software used on the device in the fabric.

l          Configure the fabric port for the newly added device.

Configuration procedure

Follow these steps to configure IRF automatic fabric for a switch:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Configure IRF automatic fabric for a switch	fabric member-auto-update software enable	Required Disabled by default

 

 

Displaying and Maintaining IRF Fabric

To do…	Use the command…	Remarks
Display the information about an IRF fabric	display irf-fabric [ port | status ]	Available in any view
Display the topology information of an IRF fabric	display ftm { information | topology-database }
Clear the FTM statistics	reset ftm statistics	Available in user view

 

IRF Fabric Configuration Example

Network Requirements

Configure unit ID, unit name, IRF fabric name, and authentication mode for four switches to enable them to form an IRF fabric as shown in Figure 1-4.

The configuration details are as follows:

l          Unit IDs: 1, 2, 3, 4

l          Unit names: unit 1, unit 2, unit 3, unit 4

l          Fabric name: hello

l          Authentication mode: simple password

l          Password: welcome

Network Diagram

Figure 1-4 Network diagram for forming an IRF fabric

 

Configuration Procedure

1)        Configure Switch A.

# Configure fabric ports.

<Sysname> system-view

[Sysname] fabric-port GigabitEthernet1/1/1 enable

[Sysname] fabric-port GigabitEthernet1/1/2 enable

# Configure the unit name as Unit 1.

[Sysname] set unit 1 name Unit1

# Configure the fabric name as hello.

[Sysname] sysname hello

# Configure the fabric authentication mode as simple and the password as welcome.

[hello] irf-fabric authentication-mode simple welcome

2)        Configure Switch B.

# Configure fabric ports.

<Sysname> system-view

[Sysname] fabric-port GigabitEthernet1/1/1 enable

[Sysname] fabric-port GigabitEthernet1/1/2 enable

# Set the unit ID to 2.

[Sysname] change unit-id 1 to 2

# Configure the unit name as Unit 2.

[Sysname] set unit 1 name unit2

# Configure the fabric name as hello.

[Sysname] sysname hello

# Configure the fabric authentication mode as simple and the password as welcome.

[hello] irf-fabric authentication-mode simple welcome

Configurations on Switch C and Switch D are similar with the above configurations.