Redistribution of IPv4 routes over IPv6 routes into BGP through tunnels (RFC 5549)

Junos OS devices can forward IPv4 traffic over an IPv6-only network, which generally cannot forward IPv4 traffic. As described in RFC 5549, IPv4 traffic is tunneled from CPE devices to IPv4-over-IPv6 gateways. These gateways are announced to CPE devices through anycast addresses. The gateway devices then create dynamic IPv4-over-IPv6 tunnels to remote CPE devices and advertise IPv4 aggregate routes to steer traffic. Route reflectors with programmable interfaces inject the tunnel information into the network. The route reflectors are connected through IBGP to gateway routers, which advertise the IPv4 addresses of host routes with IPv6 addresses as the next hop. Currently the dynamic IPv4-over-IPv6 tunnel feature does not support unified ISSU. To configure a dynamic IPv4-over-IPv6 tunnel, include the dynamic-tunnels statement at the [edit routing-options] hierarchy level.