pensive and efficient. It has a num- ber of advantages: It is easily provisioned, offers highly granular bandwidth for tactical applications, requires simpler centralized management (due to using a single protocol), requires less network equipment, makes it easy to upgrade network routers or nodes (one at a time), and makes fat pipes available. Basically, Ethernet makes a WAN look like a LAN to the end user. Ethernet also has a number of disadvantages, such as lack of reliability, packet loss, minimal QoS capabilities, and bandwidth problems. Furthermore, although the 10GigE standards are now final, they are still a long way from SDH/SONET's OC-768, or 40Gbps, and the future OC-1536 of 80Gbps. Another disadvantage is the cost to deploy fiber to the customer. Finally, the lack of valid, quantifiable SLAs, compelling applications, and formal support for VolP will slow the uptake of Ethernet. The biggest issue with Ethernet is the challenges Ethernet itself faces: the reliability and QoS issues. The 10Mbps and 100Mbps versions of Ethernet use the access technique Carrier Sense Multiple Access/Collision Detection (CSMA/CD), which permits several network nodes to share the same link. Each node can send information only if it senses that the link is not already being used. If two nodes happen to send at once, a collision occurs, and neither message gets through. Both then have to wait a random amount of time before trying again. Although 10GigE uses separate channels for sending and receiving rather than using CSMA/CD, collisions lower down the network result in unpredictable delays and high jitter. This high jitter can lead to packets being received in the wrong order, which in turn makes Ethernet unsuitable for real-time applications. There is also no way to guarantee bandwidth because every user is competing for network access. It is therefore fair to say that the 10GigE solution basically throws bandwidth at the problem. IEEE 802.1p, the QoS scheme typically used by Ethernet, does not offer the neces- sary admissio