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Understanding the QFabric System Hardware Architecture

 

QFabric System Hardware Architecture Overview

The QFabric system is a single-layer networking tier that connects servers and storage devices to one another across a high-speed, unified core fabric. You can view the QFabric system as a single, extremely large, nonblocking, high-performance Layer 2 and Layer 3 switching system. The reason you can consider the QFabric system as a single system is that the Director software running on the Director group allows the main QFabric system administrator to access and configure every device and port in the QFabric system from a single location. Although you configure the system as a single entity, the fabric contains four major hardware components. The hardware components can be chassis-based, group-based, or a hybrid of the two. As a result, it is important to understand the four types of generic QFabric system components and their functions, regardless of which hardware environment you decide to implement. A representation of these components is shown in Figure 1.

Figure 1: QFabric System Hardware Architecture
QFabric System
Hardware Architecture

The four major QFabric system components include the following:

  • Director group—The Director group is a management platform that establishes, monitors, and maintains all components in the QFabric system. It is a set of Director devices that run the Junos operating system (Junos OS) on top of a CentOS foundation. The Director group handles tasks such as QFabric system network topology discovery, Node and Interconnect device configuration and startup, and Domain Name System (DNS), Dynamic Host Configuration Protocol (DHCP), and Network File System (NFS) services. The Director group also runs the software for management applications, hosts and load-balances internal processes for the QFabric system, and starts additional QFabric system processes as requested.

  • Node devices—A Node device is a hardware system located on the ingress of the QFabric system that connects to endpoints (such as servers or storage devices) or external networks, and is connected to the heart of the QFabric system through an Interconnect device. A Node device can be used in a manner similar to how a top-of-rack switch is implemented. By default, Node devices connect to servers or storage devices. However, when you group Node devices together to connect to a network that is external to the QFabric system, the formation is known as a network Node group.

  • Interconnect devices—An Interconnect device acts as the primary fabric for data plane traffic traversing the QFabric system between Node devices. To reduce latency to a minimum, the Interconnect device implements multistage Clos switching to provide nonblocking interconnections between any of the Node devices in the system.

  • Control plane network—The control plane network is an out-of-band Gigabit Ethernet management network that connects all QFabric system components. For example, you can use a group of EX4200 Ethernet switches or a group of EX4300 Ethernet switches configured as a Virtual Chassis to enable the control plane network. The control plane network connects the Director group to the management ports of the Node and Interconnect devices. By keeping the control plane network separate from the data plane, the QFabric system can scale to support thousands of servers and storage devices.

The four major QFabric system components can be assembled from a variety of hardware options. Currently supported hardware configurations are shown in Table 1.

Table 1: Supported QFabric System Hardware Configurations

QFabric System Configuration

Director Group

Node Device

Interconnect Device

Control Plane Device

QFX3000-G QFabric system

QFX3100 Director group

QFX3500, QFX3600, and QFX5100-48S, QFX5100-48T, and QFX5100-24Q Node devices

Note: There can be a maximum of 128 Node devices in the QFX3000-G QFabric system.

QFX3008-I Interconnect device

Note: There can be a maximum of four Interconnect devices in the QFX3000-G QFabric system.

Two Virtual Chassis composed of either four EX4200-48T or four EX4300-48T switches each (for a copper-based control plane) or eight EX4200-24F or four EX4300-48P switches each (for a fiber-based control plane)

QFX3000-M QFabric system

QFX3100 Director group

Note: For a copper-based QFX3000-M QFabric system control plane network, use QFX3100 Director devices with RJ-45 network modules installed. For a fiber-based control plane network, use QFX3100 Director devices with SFP network modules installed.

QFX3500, QFX3600, and QFX5100-48S, QFX5100-48T, and QFX5100-24Q Node devices

  • There can be a maximum of 16 Node devices in the QFX3000-M QFabric system using QFX3600-I as Interconnect devices and 32 Node devices using the QFX5100-24Q as Interconnec devices.

    Note: QFX5100-24Q Interconnect devices and QFX3600-I Interconnect devices cannot be mixed on the same QFabric system.

  • For a copper-based QFX3000-M QFabric system control plane network, use QFX3500 Node devices with a 1000BASE-T management board installed. For a fiber-based control plane network, use QFX3500 Node devices with an SFP management board installed.

QFX5100-24Q or QFX3600-I Interconnect devices

Note: There can be a maximum of four Interconnect devices in the QFX3000-M QFabric system.

Two EX4200 Ethernet or two EX4300 switches

Note: For a copper-based QFX3000-M QFabric system control plane network, use EX4200-24T or EX4300-48T switches with an SFP+ uplink module installed. For a fiber-based control plane network, use EX4200-24F or EX4300-48P switches with an SFP+ uplink module installed.

To complete the system, external Routing Engines (such as the fabric manager Routing Engines, network Node group Routing Engines, and fabric control Routing Engines) run on the Director group and implement QFabric system control plane functions. The control plane network provides the control plane connections between the Node devices, the Interconnect devices, and the Routing Engines running on the Director group.

QFX3000-G QFabric System Features

A QFX3000-G QFabric system provides the following key features:

  • Support for up to 128 Node devices and 4 Interconnect devices, which provides a maximum of 6144 10-Gigabit Ethernet ports.

  • Low port-to-port latencies that scale as the system size grows from 48 to 6144 10-Gigabit Ethernet ports.

  • Support for up to 384,000 total ingress queues at each Node device to the QFabric system Interconnect backplane.

  • Support for Converged Enhanced Ethernet (CEE) traffic.

QFX3000-M QFabric System Features

A QFX3000-M QFabric system provides the following key features:

  • Support for up to 32 Node devices and 4 QFX5100-24Q Interconnect devices or 16 Node device and 4 QFX3600-I Interconnect devices.

    Note

    You may not mix QFX5100-24Q Interconnect devices with QFX3600-I Interconnect devices on the same QFX3000-M QFabric system.

  • Low port-to-port latencies that scale as the system size grows from 48 to 768 10-Gigabit Ethernet ports.