Table of Contents

1 Feature Description· 1-1

IRF Overview· 1-1

Introduction· 1-1

Application and Advantages· 1-1

Introduction to Mixed IRF· 1-2

What is a Mixed IRF· 1-2

Advantages of Mixed IRF· 1-2

2 Mixed IRF Topology· 2-1

3 Restrictions and Descriptions· 3-1

4 Versions Supporting Mixed IRF· 4-1

5 Related Documentation· 5-1

IRF Overview

Introduction

Intelligent Resilient Framework (IRF) is a software virtualization technology developed by H3C. Its core idea is to interconnect multiple devices through physical IRF ports and perform necessary configurations, and then these devices are virtualized into a distributed device. This virtualization technology realizes the cooperation, unified management, and non-stop maintenance of multiple devices.

The devices that form an IRF are called IRF members. Each of them plays either of the following two roles:

l          Master: Manages the entire IRF.

l          Slave: All member devices operating as the backups of the master are called slaves. When the master fails, the system automatically elects a new master from among the slaves.

Master and slaves are elected through the role election mechanism. An IRF has only one master at one time. Other members are the slaves.

Application and Advantages

Typically, you can deploy an IRF at the distribution layer; and you can also apply it at the access layer. An IRF is a single logical device to the users and devices of the upper layer and lower layer, as shown in Figure 1-1.

Figure 1-1 IRF networking

IRF features the following advantages:

l          Streamlined management

After an IRF is established, you can log in to the IRF system by connecting to any port of any member. When you log in to the IRF, actually you log in to the master device. You can manage all IRF members by configuring the master, for example, allocating IP addresses to the members, interconnecting the members, and running routing protocols.

l          Powerful network expansion capability

By adding member devices, the number of IRF ports and network bandwidth of the IRF system can be easily expanded. Each member device has its own CPU and they can process and forward protocol packets independently; therefore, the processing capability of the IRF system also can be easily expanded.

l          High reliability

An IRF system comprises multiple member devices: the master runs, manages and maintains the IRF, whereas the slaves process services as well as functioning as the backups. As soon as the master fails, the IRF system elects a new master immediately to prevent service interruption and implement 1:N backup.

Besides, not only the IRF links of members can be aggregated, but also the physical links between the IRF system and the upper or lower layer devices can be aggregated, and thus the reliability of the IRF system is increased through the link backup.

Introduction to Mixed IRF

At present, the IRF feature is widely used and has users’ approval due to its redundant and reliable performance, convenient and fast configuration, and unified configuration interface. Previously, you can establish an IRF (an IRF can comprise at most nine switches) by connecting only switches of the same series, S5800 series switches or S5820X series switches, and you cannot establish a mixed IRF that comprises both S5800 series and S5820X series switches.

What is a Mixed IRF

Now, to better meet the users’ requirements, the mixed IRF feature is realized on the S5800 series and S5820X series switches, which means you can establish an IRF that comprises both S5800 series and S5820X series switches.

Advantages of Mixed IRF

The mixed IRF feature can not only provide mutual backup, redundant reliability, and centralized management, but also perform unified management for GE and 10 G networks, and thus reduces maintenance costs. Besides, the mixed IRF can expand the GE and 10 G port density flexibly.

For the implementation of the mixed IRF, the connection scheme among devices and the configuration schemes are identical with those when you build an IRF using either the S5800 series or S5820X series switches.

An IRF typically adopts daisy chain connection or ring connection:

l          Daisy chain connection: Given a device, its IRF port 1 is connected to IRF port 2 of another device, and its IRF port 2 is connected to IRF port 1 of a third one; devices are connected to form a single straight connection, as shown in Figure 2-1.

l          Ring connection: Given a device, its IRF port 1 is connected to IRF port 2 of another device, and its IRF port 2 is connected to IRF port 1 of a third one, as shown in Figure 2-1.

Figure 2-1 Physical connections of IRF

The orange lines in the figure represent IRF cables. The IRF cable can be composed of either one physical cable or multiple physical cables.

Figure 2-2 Recommended network diagram for mixed IRF

Support for software functions on the S5800 series and S5820X series is different. Note the differences mentioned in the following table when you configure these functions in a mixed IRF:

Table 3-1 Function matrix for the S5800 and S5820X

For functions supported by both the S5800 series and the S5820X series, the implemented capabilities are different. Note the differences mentioned in the following table when you configure these functions in a mixed IRF:

Table 3-2 Function capability matrix of the S5800 and S5820X series

In a mixed IRF, you need to note the following items referring to ARP, ND, and multicast entries:

l          Suppose an IRF comprising S5800 series switches has already learned 16K ARP entries. If you add an S5820X series into the IRF, a mixed IRF is formed. Then, the exceeded ARP entries (8K) on the S5800 series will be converted to blackhole entries, and packets that need to be forwarded based on the blackhole entries will be discarded directly.

l          Suppose a mixed IRF comprising several S5800 series switches and one S5820X series switch has already learned 16K ARP entries (8K entries are maintained on the S5820X series, and 8K normal entries and 8K blackhole entries are on the S5800 series switches). If the S5820X switch leaves the IRF, the ARP entries on the S5800 series cannot be automatically cleared; therefore, 8K blackhole entries are still on the S5800 series switches. The IRF can continue to learn ARP entries until the number of entries reaches 16K only after you clear the ARP entries with the reset arp command or after the blackhole entries age out (the aging time of a blackhole entry is the same as that of a normal ARP entry).

l          The S5800 series and S5820X series switches use the hash algorithm to maintain the ND and multicast entries. After being hashed, if a new ND entry or multicast entry is the same as that existing on one member device, but different from that on another, this entry cannot be added successfully, and the corresponding data cannot be forwarded normally.

S5800_5820X-CMW520-F1110 and later versions support mixed IRF.

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