A TCP session using port 8179 is
established between the nodes using the peer IP and the cluster source IP.
The control plane session requires a direct link
btween the nodes (peer-interface) to be operational.The control plane session is used to
exchange the following information:
MCT client discovery
MCT client VLAN/BD configuration
information
Route exchanges – MAC, MAC/IP,
IGMP
Keep-alive peer IP in auto discovery
mode
Other required state/signaling
for protocols, such as PIM, and mac-move detection
A cluster control protocol (CCP) session is used to exchange MAC, MAC/IP and IGMP
routes between the MCT peers. A cache is created within the MCT process to hold MAC, ARP
and IGMP routes. For the VLANs/BDs that are shared between the MCT nodes, all local
routes received from L2, ARP and multicast modules are stored in L2RIB and advertised to
the MCT peer. Routes in L2RIB have the following possible sources:
Locally learned
MCT Peer
A route selection algorithm is run to determine the best route and download only that
route for installation in hardware. L2RIB also generates a sequence number for the
routes and passes this on to BGP for MAC mobility and MAC dampening purposes. L2RIB does
not include a dampening logic and relies on the MAC move detection feature to detect and
mitigate layer-2 loops.
Local routes from l2/arp/multicast modules are cached and advertised to mct-peer and BGP
based on vlan/bd extension. Similarly remote routes from MCT peer and BGP are cached in
mct process and advertised to L2/ARP/Multicast processes for hardware programming.
