The ship uses a 4Mbps down, 2Mbps up C-band satellite connection to reach shore. The service can burst above that, but at a premium. "It's managed very tightly," Schmidt says, in order to keep costs down. "We time transmissions for applications during known downtimes in demand." The liner also uses WAN optimization gear from Blue Coat and Riverbed to make more efficient use of these links.

The 1,181-foot-long craft has been afloat for more than a year, but planners were busy long before that designing and testing its networking gear, Schmidt says.

The work was done with a combination of Royal Caribbean staff, Cisco Services (it's a Cisco network) and other consultants planning, staging and testing the network ashore before boxing it up for installation aboard the vessel. "We don't have time to do all that on site," Martin says.

All traffic runs across a routed 10Gbps MPLS backbone anchored by Cisco 6500 series switches that support a total of 27,000 gigabit Ethernet ports. as well as VLANs help impose QoS on different classes of service. The network features two data centers so if one data center goes down the other can step in. "Critical applications have an environment to fail to," Martin says. The network has 37 remote distribution points, each fed by more than one fiber source -- the ship contains nearly 2 million feet of fiber -- whose generator power is backed up by redundant UPSs that are in turn backed up by redundant UPSs, Martin says.

The network is routed via MPLS to impose QoS on different classes of traffic, including passenger communications, voice, secure traffic and internal corporate data. Throughput has to be high because traffic also includes high-definition IP TV to passenger cabins.