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Understanding Virtual Chassis Ports in an EX8200 Virtual Chassis

A Virtual Chassis port (VCP) in an EX8200 Virtual Chassis is any port whose function is to send and receive Virtual Chassis Control Protocol (VCCP) traffic to create, monitor, and maintain the Virtual Chassis. VCPs are responsible for creating, monitoring, and maintaining the Virtual Chassis as well as carrying data traffic through the Virtual Chassis.

All Gigabit Ethernet ports on the 10/100/100BASE-T RJ-45 Virtual Chassis Control Interface (VCCI) modules and all small form-factor pluggable (SFP) ports on the 1000BASE-X SFP VCCI modules on the XRE200 External Routine Engine are VCPs. Port 0 on the XRE200 External Routing Engine is also a VCP. You can use VCPs to connect Juniper Networks EX8200 Ethernet 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.


To connect a 1000BASE-X SFP interface on the XRE200 External Routing Engine to an EX8200 switch, you must use an intermediary switch. The intermediary switch is required because the management interface (labeled MGMT) on the Routing Engine (RE) module or the Switch Fabric and Routing Engine (SRE) module in the EX8200 switch does not support SFP connections. See Understanding Long-Distance Virtual Chassis Port Configuration for an EX8200 Virtual Chassis.

VCP links are also needed in an EX8200 Virtual Chassis to send and receive VCCP traffic between two EX8200 member switches. You must explicitly configure VCP links between two EX8200 switches; otherwise, the switches detect the link as a network link. For information regarding which ports on an EX8200 switch can be configured as VCPs, see Line Card Model and Version Compatibility in an EX8200 Switch.

Multiple VCP links can be configured between two EX8200 member switches; these links will automatically form a link aggregation group (LAG). See Understanding Virtual Chassis Port Link Aggregation in an EX8200 Virtual Chassis.

Figure 1 shows a two member Virtual Chassis configured in a full mesh topology and highlights which VCP links must be user-configured.