Supported Platforms
Understanding EX8200 Virtual Chassis Components
An EX8200 Virtual Chassis allows you to interconnect up to four Juniper Networks EX8200 Ethernet Switches and run them as a single network entity. You interconnect the EX8200 switches by connecting them to an XRE200 External Routing Engine.
This topic covers:
Virtual Chassis Ports (VCPs)
A Virtual Chassis port (VCP) in an EX8200 Virtual Chassis is any interface whose function is to send and receive Virtual Chassis Control Protocol (VCCP) traffic to create, monitor, and maintain the Virtual Chassis. VCPs are used for creating, monitoring, and maintaining the Virtual Chassis as well as carrying data traffic through the Virtual Chassis.
All Gigabit Ethernet ports on the Virtual Chassis Control Interface (VCCI) modules on the XRE200 External Routine Engine are VCPs. Port 0 on the XRE200 External Routing Engine is also a VCP. You use VCPs to connect EX8200 switches to the external Routing Engine to form a Virtual Chassis and also to connect XRE200 External Routing Engines together to provide external Routing Engine redundancy within the Virtual Chassis. Any link connecting an XRE200 External Routing Engine to an EX8200 switch or to another XRE200 External Routing Engine, therefore, is automatically a VCP link. No user configuration is required to configure these VCP links.
The small form-factor pluggable (SFP) ports on the 4-port 1000BASE-X SFP VCCI module are also VCPs. You can use these ports to directly connect XRE200 External Routing Engines together within an EX8200 Virtual Chassis with no user configuration. You can also use these SFP ports to connect an XRE200 External Routing Engine to an EX8200 switch within a Virtual Chassis when an intermediary switch is used to convert the SFP fiber-optic connection to a copper connection. This conversion is necessary because the management ports (labeled MGMT) on EX8200 switches do not support fiber-optic connections. See Configuring a Long-Distance Virtual Chassis Port Connection for an EX8200 Virtual Chassis.
VCP links are also needed in an EX8200 Virtual Chassis to send and receive VCCP traffic between two EX8200 switches. You must explicitly configure VCP links between two EX8200 switches; otherwise, the switches detect such links as network links.
Master External Routing Engine Role
The function of each hardware device in a Virtual Chassis is determined by that device’s role.
The master role in an EX8200 Virtual Chassis is assigned to an XRE200 External Routing Engine only. The XRE200 External Routing Engine in the master role:
- Controls most Routing Engine functions for all switches in the Virtual Chassis.
- Manages the Virtual Chassis configuration.
- Provides a single point where you can view all functionality for all devices in the Virtual Chassis.
- Runs the Juniper Networks Junos operating system (Junos OS).
When a single XRE200 External Routing Engine is connecting an EX8200 Virtual Chassis and no backup external Routing Engine is configured, the single external Routing Engine is assigned the master role. When a backup external Routing Engine is part of the Virtual Chassis, the external Routing Engine with the most uptime functions as the master.
Backup External Routing Engine Role
The function of each hardware device in a Virtual Chassis is determined by that device’s role.
The external Routing Engine that functions in the backup role:
- Maintains a state of readiness to take over the master role if the master fails.
- Runs Junos OS.
- Synchronizes with the master, so that it is prepared to preserve routing information and maintain network connectivity without disruption if the master external Routing Engine becomes unavailable.
You must have two external Routing Engines in an EX8200 Virtual Chassis configuration to have an external Routing Engine in the backup role. When a backup external Routing Engine is part of the Virtual Chassis, the external Routing Engine with the lesser amount of uptime functions as the backup external Routing Engine.
Linecard Role
All EX8200 switches in an EX8200 Virtual Chassis are assigned the linecard role. Switches in the linecard role:
- Forward network traffic.
- Do not run the chassis control protocols.
- Can detect certain error conditions (such as an unplugged cable) on any interfaces that have been configured on them through the master.
Member Switch and Member ID
An EX8200 Virtual Chassis contains member IDs 0 through 9. Member IDs 0 through 7 must be configured as EX8200 switches.
Member IDs 8 and 9 must be configured as XRE200 External Routing Engines. An XRE200 External Routing Engine automatically assumes the next available member ID if a Virtual Chassis configuration has not been configured and committed. The external Routing Engine does not function properly until it is configured as member 8 or 9, however.
Table 1 summarizes EX8200 Virtual Chassis roles and member IDs.
Table 1: EX8200 Virtual Chassis Roles and Member IDs
| Hardware | Role | Member IDs |
|---|---|---|
EX8208 or EX8216 switch | Linecard | 0–7 |
XRE200 External Routing Engine | Master or backup | 8 or 9 |
Virtual Chassis Identifier (VCID)
All members of a Virtual Chassis configuration share one Virtual Chassis identifier (VCID). This identifier is derived from internal parameters. When you are monitoring a Virtual Chassis configuration, the VCID is displayed in the user interface.
