Juniper EX8200 Virtual Chassis Best Practice Guidelines
This document outlines best practices for deploying and configuring Juniper Networks EX8200 Virtual Chassis configurations, focusing on achieving high availability, resiliency, and efficient network fabric implementation in campus and data center environments.
Introduction
Modern enterprise networks face increasing demands from real-time applications. Traditional LAN designs relying on Spanning Tree Protocol (STP) for loop prevention can be complex, underutilize network capacity, and require intensive protocols like Virtual Router Redundancy Protocol (VRRP), limiting scalability. Juniper Networks Virtual Chassis technology offers an innovative approach to building highly available and resilient Layer 2 networks without these traditional protocol dependencies.
Scope
This guide provides network architects and engineers with best practices for designing, deploying, and configuring Juniper Networks EX8200 Ethernet switches with Virtual Chassis technology. It covers EX8200 Virtual Chassis architectures, deployment using hardware components and connections, and migration, failover, and nonstop software upgrade (NSSU) scenarios.
Terminology
- XRE200: Juniper Networks XRE200 External Routing Engine.
- LCC: Line card chassis (an EX8200 member chassis).
- SRE: Switch Fabric and Routing Engine.
- VCP: Virtual Chassis port, used for Virtual Chassis Control Protocol traffic.
- FPC: Flexible PIC Card (line card module).
- Network ports: Ports that carry only data traffic, not Virtual Chassis control traffic.
- PFE: Packet Forwarding Engine.
Design Considerations
EX8200 Virtual Chassis Configurations
The EX8200 Virtual Chassis technology allows up to four EX8200 chassis to interconnect as a single logical device. This architecture utilizes redundant external Routing Engines (XRE200) capable of managing multiple chassis via 1GbE or 10GbE Virtual Chassis Ports (VCPs). The XRE200 acts as the controller, separating it from the chassis Routing Engine. Interconnections are made via dedicated VCP links, which handle control plane traffic and do not carry data traffic.
A typical configuration involves an active and a backup XRE200 connected to EX8200 member switches (Line Card Chassis - LCCs). These connections form the control plane. Data traffic between LCCs is handled via 10GbE links, which can also carry control traffic in case of dedicated VCP failure. EX8200 Virtual Chassis can support EX8208 (eight-slot) and EX8216 (16-slot) chassis.
Diagram Description (Figure 1): A diagram illustrates a two-member EX8200 Virtual Chassis configuration with two XRE200s. It shows active and backup XRE200s connected via 1GbE copper links to the internal Routing Engines of two EX8200 member switches. 10GbE fiber links form intra-Virtual Chassis connections between the member switches, and an Inter-XRE200 connection is also shown.
EX8200 Virtual Chassis Ports
Virtual Chassis Ports (VCPs) are essential for establishing, monitoring, and maintaining the Virtual Chassis configuration. There are three types of VCPs:
- Inter-XRE200: Connects XRE200s to each other.
- XRE-LCC: Connects XRE200s to EX8200 member chassis.
- Intra-Virtual Chassis: Connects EX8200 member chassis to each other.
Dedicated VCPs (Inter-XRE200 and XRE-LCC) carry control traffic. Intra-Virtual Chassis ports can carry both data and control traffic, especially during dedicated VCP failures. All GbE ports on the XRE200's Virtual Chassis Control Interface (VCCI) modules function as VCPs. On EX8200 member chassis, VCPs are typically configured on 10GbE ports, often in pairs, and can form Link Aggregation Groups (LAGs) for increased bandwidth and redundancy.
Comparison Between EX4200 and EX8200 Virtual Chassis Configurations
The EX4200 supports up to 10 switches in a Virtual Chassis with inherent Routing Engine support, whereas the EX8200 uses external XRE200s for up to four chassis. Key differences include:
- Mastership: EX4200 members can be masters; EX8200 mastership is fixed to XRE200s.
- VCP Usage: EX8200 dedicated VCPs carry control traffic only, while intra-VCPs carry data and control. EX4200 VCPs carry both.
- Load Balancing: EX8200 uses intelligent chassis-local load balancing, reducing traffic over VCP links, unlike the EX4200's hash-based LAG load balancing.
Diagram Description (Figure 2): This diagram shows a four-member EX8200 Virtual Chassis with a full mesh connection between all member switches (LCCs) and access switches. It illustrates how traffic between access switches is switched locally within the Virtual Chassis, minimizing VCP traffic.
EX8200 Virtual Chassis High Availability and Resiliency
The EX8200 Virtual Chassis architecture is designed for high availability and resiliency, eliminating single points of failure. This is achieved through:
- Hardware Redundancy: Dual external XRE200 Routing Engines provide control plane redundancy, with one active and one hot standby. Each EX8200 chassis also has redundant Switch Fabric and Routing Engines (SREs).
- Control Plane Redundancy: Features like Graceful Routing Engine Switchover (GRES) and Nonstop Active Routing (NSR) ensure continuous operation and protocol session preservation during Routing Engine switchovers. Nonstop Bridging (NSB) is also supported.
- Data Plane Redundancy: Multi-Link Aggregation Groups (LAGs) connecting access switches to different LCC members provide redundant data paths.
- Nonstop Software Upgrade (NSSU): This feature allows Junos OS upgrades with minimal traffic disruption by upgrading components sequentially, leveraging GRES and NSR.
The Makeup of an EX8200 Virtual Chassis
An EX8200 Virtual Chassis is formed by two XRE200 External Routing Engines and up to four EX8200 chassis. The XRE200s manage the Virtual Chassis, with one acting as the master and the other as a backup. EX8200 chassis function as Line Card Chassis (LCCs), forwarding data traffic. Member IDs are assigned from 0-9, with 0-7 for LCCs and 8-9 for XRE200s. Interface numbering follows the standard Junos OS format (type-
Table 2: EX8200 Virtual Chassis Member IDs and Roles lists device types (EX8208/EX8216 switch, XRE200) and their corresponding member IDs and roles.
Table 3: EX8216 or EX8208 FPC and Interface Numbering details FPC numbering based on member ID for different switch models.
Connecting and Configuring
Connecting an XRE200 into an EX8200 Virtual Chassis Configuration
GbE interfaces on the active and standby XRE200s connect to the Routing Engine management ports (converted to VCPs) of the EX8200 chassis. XRE200s can also connect to each other directly via GbE interfaces for redundancy.
Diagram Description (Figure 3): This diagram shows a two-member EX8200 Virtual Chassis with XRE200s connected to each other and to the EX8200 switches via GbE interfaces. It illustrates intra-XRE connections for HA, active/standby XRE to internal RE connections, and 10GbE LAG intra-Virtual Chassis connections.
Building Virtual Chassis Configurations over Long Distances
For distances exceeding standard cable limits, intermediate Layer 2 switches (e.g., Juniper EX2200) can act as media converters to enable connections over fiber links. This requires configuring specific ports on the intermediate switches for VLANs and Unidirectional Failure Detection (UFD) protocol for link failure detection. Jumbo frames are also configured on interfaces for optimal performance.
Diagram Description (Figure 4): This diagram depicts a two-member EX8200 Virtual Chassis configuration over long distances. It shows XRE200s connected to intermediate EX2200 switches, which are then connected via fiber links. Copper ports on the switches are paired with fiber ports for UFD configuration.
New EX8200 Virtual Chassis Configuration Steps
Creating a two-member EX8200 Virtual Chassis involves several key steps:
- Upgrade all XRE200s and EX8200 switches to the same Junos OS version (e.g., 11.1 recommended).
- Prepare EX8200 switches for Virtual Chassis mode using the
set chassis virtual-chassiscommand. - Create a preprovisioned Virtual Chassis configuration on the master XRE200, specifying serial numbers, member IDs, and roles for all members. Non-provisioned configurations are not supported.
- Connect EX8200 switches to the XRE200s via VCPs.
- Interconnect the XRE200s.
- Convert 10GbE network ports on EX8200 switches to Virtual Chassis ports (VCPs).
- Interconnect EX8200 switches using these converted 10GbE VCPs.
Diagram Description (Figure 5): Shows a redundant pair of EX8200 switches in standalone mode, using VRRP and RTG LAGs, with traffic flowing over the master switch.
Diagram Description (Figure 6): Illustrates traffic flow through the backup EX8200 switch while the master is prepared for Virtual Chassis configuration.
Diagram Description (Figure 7): Depicts a single-member EX8200 Virtual Chassis formed, with traffic still flowing through the backup EX8200.
Diagram Description (Figure 8): Shows traffic migrated from the backup EX8200 to the single-member Virtual Chassis.
Diagram Description (Figure 9): Illustrates traffic flow through a single-member EX8200 Virtual Chassis while the backup EX8200 joins the configuration.
Diagram Description (Figure 10): Shows traffic load-balanced over both EX8200 switches after migration to a two-member Virtual Chassis.
Diagram Description (Figure 11): Presents the logical network topology of the EX8200 Virtual Chassis configuration after migration.
Migrating EX8200 Standalone Switches to EX8200 Virtual Chassis Configurations
The process involves upgrading switches, detaching them from existing connections, attaching them to XRE200s, configuring them in Virtual Chassis mode, and then re-establishing access switch links. VRRP must be disabled on the EX8200 switches once they are in Virtual Chassis mode.
EX8200 Virtual Chassis High Availability Best Practices
To achieve a highly resilient configuration with no single point of failure, the following are recommended:
- A fully meshed redundant EX8200 Virtual Chassis configuration with multiple members and interconnections.
- GRES enabled on both XRE200s.
- NSR enabled for routing protocols.
- Multi-LCC LAGs for connecting access switches.
- LACP configured on LAGs in slow periodic mode.
- STP and VRRP disabled.
Diagram Description (Figure 12): Shows a two-member EX8200 Virtual Chassis with dual-homed access devices, illustrating a highly available setup.
Diagram Description (Figure 13): Depicts a pair of two-member EX8200 Virtual Chassis configurations interconnected via MPLS, showcasing advanced high availability and resiliency.
Table 4: High Availability and Resiliency Convergence Test Results details convergence times for various failure events, such as LAG member disconnects, line card removal, and Routing Engine switchovers, demonstrating sub-second packet loss in most critical scenarios.
EX8200 Virtual Chassis over Long Distances Configuration Steps
This section details the physical connections and configuration steps for intermediate switches (like EX2200) used as media converters for long-distance connections. It covers VLAN configuration, Unidirectional Failure Detection (UFD) protocol setup, 802.3ah configuration for fiber links, and Jumbo frame settings.
Diagram Description (Figure 14): Illustrates two XRE200s connected to each other via EX2200 switches over a long distance, highlighting the fiber and copper connections for UFD.
Conclusion
Juniper EX8200 switches with Virtual Chassis technology provide a robust solution for core/aggregation switching, offering multipathing, eliminating STP inefficiencies, and simplifying management. This cost-effective solution extends switching capacity, protects against single points of failure, and reduces the number of devices to manage, ultimately lowering operational costs.
About Juniper Networks
Juniper Networks is a leader in network innovation, providing software, silicon, and systems for devices, data centers, and cloud providers. They transform the experience and economics of networking. More information is available at www.juniper.net.
