The color of the network page denotes the network cabling in the physical world.

RED = Remote Console , IPMI, iLO, iDRAC, etc.
YELLOW = control plane of openstack, all network traffic related to mysql, keystone, rabbitmq, etc. lives here.
GREEN = vmnet. All network traffic related to vm's communicating with each other / internet lives here.
BLUE =  storage. All network traffic related to storage (nfs / iscsi / etc.) lives here.
WHITE = backup. All network related traffic related to making storage backups live here.

White is currently not yet implemented due to a lack of hardware within Linuxfriendly.