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Reduce Network Complexity and Operation Costs with Juniper Networks Virtual Chassis Technology

Juniper Networks Virtual Chassis technology helps address the growing complexity and operation costs of organizations’ networks. Read on to learn how Virtual Chassis technology simplifies networking operations and architecture, increases scalability and performance, and decreases operation costs.

The Complexity Issue

Many of today’s data center and enterprise networks utilize three-tier architectures that are complex and inflexible, causing poor performance and excessive resource consumption. Three-tier, or three-layer, architectures consist of core, access, and distribution layers. The access layer consists of switches that connect client devices to the network, such as workstations, desktops, and servers. The distribution layer consists of devices in charge of routing and filtering. The core layer consists of switches and routers that move information between devices within the distribution layer. Core layer devices are typically high-speed and powerful.

Poor performance in three-tier architectures comes from latency, delays in network convergence due to Spanning Tree Protocol (STP), or even Rapid Spanning Tree Protocol (RSTP), and limited bandwidth. Virtualization compounds the issues of latency, delays in network convergence, and limited bandwidth. Virtual infrastructures require networks to have the ability to support virtual machine migration and adapt to these changes quickly without service disruption. Excessive resource consumption comes from adding more devices to meet increased network demands, and this high number of independent devices make routine network administrative tasks challenging and inefficient.

How It Works

Virtual Chassis technology allows multiple interconnected switches to behave, operate, and be managed as a single logical, high-bandwidth device, simplifying networks by reducing the number of managed devices and helping networks scale without the operation overhead associated with maintaining systems of independent switches. Juniper Networks Virtual Chassis technology is available on EX and QFX series ethernet switches.

Multiple EX and QFX series switches connect via a high-speed backplane using dedicated Virtual Chassis ports or optional 10GbE or 40GbE fiber ports configured as Virtual Chassis ports. Up to 10 interconnected switches can be managed as a single device, or in other words Virtual Chassis technology can reduce the number of managed devices by a factor of 10, thereby greatly decreasing operating expenses and simplifying system maintenance and management. Juniper Networks Junos® Space Network Director operating system can configure and manage the Virtual Chassis configuration as a single, logical device.

The Benefits

Virtual Chassis technology allows for greater availability, up to five nines, which enables nonstop business operations. There is uninterrupted connectivity due to master selection occurring automatically, and nearly eliminated downtime from NSSU (nonstop software upgrade) and VRRP (Virtual Router Redundancy Protocol).

Improved performance, scalability, and flexibility is also witnessed. Flexible scaling occurs from the ability to span access and aggregation network tiers and interconnect up to 10 switches. Flexible growth occurs from pay-as-you-grow scalability on fixed configuration switches. Location flexibility occurs from the ability to extend Virtual Chassis configurations across vertical and horizontal distances of up to 80 km with redundant fiber links.

Other important benefits from Virtual Chassis technology include consistent implementation, decreased latency, and lower operational expenditure. With all EX and QFX series switches running the same modular Juniper Networks Junos operating system, there is consistent control plane feature implementation as well as simplified network administration, maintenance, and learning. Decreased latency comes from the ability to have multiple interconnected devices operating like a single logical device. Lower operational expenditure is due to the reduced rack space, power, and cooling resource consumption as well as the improved link utilization and application performance from the network by eliminating STP and related delays.

Conquering the Complexity Issue

Virtual Chassis technology allows data center architectures to collapse tiers and flatten the network from three to two layers. This is possible by interconnecting Virtual Chassis configured switches, conserving access ports, and merging what would be many LANs into one, thereby decreasing the layers of switching needed for network access. The flexibility extends a single Layer 2 access network beyond a single rack which decreases the effort needed for network changes such as live server migrations. The flexibility also extends Layer 2 access between sites up to 80 km apart which greatly decreases the effort needed to deploy new services. Virtual Chassis technology minimizes data center network complexity and also delivers the benefits of top-of-rack and end-of-row access switch deployments without having to choose between them. With single managed devices, connections for customers are intra-rack which simplifies cable management, configuration changes are easier, management of one IP address, one image and one configuration decreases maintenance efforts, and there is flexibility from having uplinks in the core.

When it comes to enterprise networks, campuses of up to 5,000 access points can collapse aggregation and core layers. There is a reduced number of required 10GbE uplinks and overall number of managed devices by interconnecting up to 10 Virtual Chassis switches. Additionally, up to four EX2200 switches can be interconnected in low-density wiring closets. In larger campuses, again there is a reduced number of managed devices which eliminates the need for STP and related delays from network convergence thereby improving performance and resource utilization. Virtual Chassis technology allows for cost-efficient use of resources in corporate networks. The efficient use of access and uplink ports optimizes rack space, power, and cooling resources. By eliminating layers, resources and equipment for planning, deployment, implementation, and operation are reduced. Virtual Chassis technology also improves performance in enterprise networks. There is decreased latency by flattening the network. Bandwidth is preserved from inter-switch traffic routed over the backplane and not flooding traffic over access points. Backplane connections also decrease the number of devices and conserves resources. Node and link failover times are measured in subseconds, and there is no need for external Layer 2 control plane protocol like STP, providing a loop-free topology.


Through Virtual Chassis technology, EX and QFX series switches deliver highly scalable solutions that decrease network complexity, increase flexibility, improve performance, and reduce resource consumption. Additionally, port densities and the Junos operating system increase operational efficiency by improving resource and network asset utilization. The decreased operations, maintenance, and troubleshooting costs that result deliver more cost-effective solutions for data center and enterprise networks.