Understanding ICCP in a Junos Fusion using Dual Aggregation Devices
This topic describes the Inter-Chassis Control Protocol (ICCP) in a Junos Fusion. It covers:
ICCP in a Junos Fusion Overview
Inter-Chassis Control Protocol (ICCP) is used in MC-LAG topologies to exchange control information between the devices in the topology. See Multichassis Link Aggregation Features, Terms, and Best Practices for additional information on ICCP.
A Junos Fusion with two aggregation devices is an MC-LAG topology, and is therefore always running ICCP as the control protocol. A Junos Fusion using a single aggregation device is not an MC-LAG topology and does not run ICCP.
A dedicated ICCP link is highly recommended in a Junos Fusion deployment, but is not required. ICCP traffic is transmitted across the ICL when an ICCP link is not configured. An ICCP link can be one link or an aggregated ethernet interface. In most Junos Fusion deployments, we recommend using a 40-Gbps link or an aggregated ethernet interface as the ICCP link.
Automatic ICCP Provisioning
Junos Fusion supports automatic ICCP provisioning, which automatically configures ICCP in a dual aggregation device setup without any user action. Automatic ICCP provisioning is enabled by default and is often the preferred method of enabling ICCP for a Junos Fusion in greenfield deployments that are not being integrated into an existing network. If you are installing your Junos Fusion in an environment that doesn’t have to integrate into an existing campus network, you can usually ignore manual ICCP configuration processes and allow automatic ICCP provisioning to enable ICCP.
Many Junos Fusion installations occur in brownfield deployments and the Junos Fusion has to be integrated into an existing network. Brownfield deployments often have a need to maintain existing ICCP settings, in particular in scenarios where a Junos Fusion is replacing an MC-LAG topology or is supporting a network that includes other MC-LAG topologies. ICCP must be configured manually in these scenarios.
See Enabling Junos Fusion Enterprise on an Enterprise Campus Network for an example of a Junos Fusion Enterprise deployment that manually configures ICCP.