Juniper JUNOS OS 10.4 - FOR EX REV 1 Manual page 1183

Understanding Virtual Chassis Ports in an EX8200 Virtual Chassis
Copyright © 2010, Juniper Networks, Inc.
Chapter 44: EX8200 Virtual Chassis—Overview, Components, and Configurations
EX8200 Virtual Chassis Overview on page 1071
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 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 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.
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. Only
10–GigabitEthernet links can be configured as VCPs between EX8200 member switches.
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" on page 1080.
Figure 27 on page 1080 shows a two member Virtual Chassis configured in a full mesh
topology and highlights which VCP links must be user-configured.
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