- An important concept in networking is network storage. There are predominantly two types of network storage. Network Attached Storage, NAS and Storage Area Networks, SAN. So what are the differences between the two? Let's start by looking at NAS. NAS is a file-level computer storage server type. It's typically connected to a computer network and is specialized for serving files by either hardware, software or configuration. NAS systems are networked and will all often contain more than one storage drive, arranged in storage containers or configured as RAID. They typically provide access to the files using file sharing protocols, like FTP, HTTP, NFS and SFTP. NAS network storage allows you to take a storage device and connect it to any network. However, as NAS provides file-level access, if you need to change just a single character inside of an entire file, you do need to rewrite the entire file onto that NAS device. There are three different ways to implement NAS storage. First is to use a computer-based NAS, using a personal computer or server. This is the most power-hungry solution that has the most powerful functions. Second is to use the embedded system NAS. This uses ARM, or MIPS-based processor architecture and operating systems to run an NAS server. And third is to use an ASIC-based NAS. This NAS system uses an ASIC chip to implement TCP/IP and a file system. The chip doesn't need an OS as all the performance-related operations are done by hardware acceleration circuits. So that's NAS. Next, let's looks at SAN. So Storage Area Networks, SAN, are computer networks that provide block-level data storage as opposed to the file-level data storage that NAS provides. Using block-level storage makes it more efficient than file-level as if you need to change a byte of data within a file, you only need to edit the block of data, not the entire file, making it very similar to editing data on a traditional computer with the storage drive. SANs have their own networking devices, such as SAN switches and information is passed between three layers, the host layer, fabric layer and the storage layer. SAN makes use of different network protocols too, like ATA over ethernet, FCP, iSCSI and SCSI RDMA protocol. And that's it for this video.