Because hosts access NAS storage resources over the LAN, the LAN can become a bottleneck. Even on a Gigabit Ethernet network, storage traffic must compete with other data network traffic. Most NAS appliances are optimized for file storage, and TCP/IP is not optimized for block-level storage. NAS performance is often less robust for applications that use block-level storage, such as databases, although some vendors have introduced NAS products that are optimized for databases. The NAS server itself can become a bottleneck, although this can be mitigated by designing the NAS device with more CPU power and/or a TCP/IP accelerator.