Difference between SAN v/s NAS

Major Differences
NAS		SAN
Almost any machine that can connect to the LAN (or is interconnected to the LAN through a WAN) can use NFS, CIFS or HTTP protocol to connect to a NAS and share files.		Only server class devices with SCSI Fibre Channel can connect to the SAN. The Fibre Channel of the SAN has a limit of around 10km at best
A NAS identifies data by file name and byte offsets, transfers file data or file meta-data (file's owner, permissions, creation data, etc.), and handles security, user authentication, file locking		A SAN addresses data by disk block number and transfers raw disk blocks.
A NAS allows greater sharing of information especially between disparate operating systems such as Unix and NT.		File Sharing is operating system dependent and does not exist in many operating systems.
File System managed by NAS head unit		File System managed by servers
Backups and mirrors (utilizing features like NetApp's Snapshots) are done on files, not blocks, for a savings in bandwidth and time. A Snapshot can be tiny compared to its source volume.		Backups and mirrors require a block by block copy, even if blocks are empty. A mirror machine must be equal to or greater in capacity compared to the source volume.

Difference between Netbackup and Backupexec

Difference Between Netbackup and Backupexec

Well we know Netbackup is for Enterprise level and Backup is for Mid-sized environments , I would like to highlight few more difference's which are mainly considered while discussing about these two leading backup products from Symantec.

  

Category	Backup_Exec	Netbackup
Latest Version	2014	7.6.0.2
Database in the backend	Microsoft SQL	Sybase
Tape Format	BKF	TAR
Reporting	Native	OpsCenter
Management	CASO (Central Admin Server Option) can manage multiple media server deployed across Domain.	NetBackup Master Server, can manage multiple media server, SAN media servers and clients centrally.
Can read from NetBackup/Backup Exec	Not supported to read NetBackup images to Backup Exec	Supported until BE 2012 , later versions not supported
NDMP	Supported	Supported
De-Duplication	Supported	Supported
GRT	Supported	Supported
BMR	Supported	Supported
Tape Library, VTL and autoloader	Supported	Supported
Tape-out protocols FC & ISCSi	Supported	Supported
Multistreaming backups	Not Supported	Supported
Multiplexed backups	Not Supported	Supported
Vmware and Hyper-V Environments	Supported	Supported
Offline and Online backups	Supported	Supported
Automatic scheduled and Manual Backups	Supported	Supported
Media Server Support	Windows Only	Windows as well as UNIX
Client Support	Windows and Linux Only	Windows as well as UNIX
Disk Based Backups	Supported	Supported
Encryption	Supported	Supported
SAN backups	Supported	Supported
Convert backups to virtual machines	Supported	Supported

Brief description of Ports numbers, MAC addresses, IP addresses

Brief Description:

Port number is used to identify an application/services which you want to talk to on your system. Some predefined ports like 80 = HTTP server, 23 = Telnet.

You identify a host uniquely (globally) by its IP address. So if I ever wanted to access your laptop via telnet then I'd use the IP address given to you by your ISP and the port 23 (more on this later).

You cannot contrast MAC addresses with port number directly. With MAC addresses you can uniquely identify a network card.

But you must be wondering how these things fit together!More Details:

You first need to understand the significance of abstraction in networking. You build things on top of some other things. You don't worry about how things are done below you.

Say you want to get a webpage from Google.

1. You say to the IP layer that connect with Google's IP address and give this packet to port 80 on the other side (Google's web server). You don't worry how it is delivered.. the IP layer could even use pigeons to transport your packet after them out. But you don't care, you just wait for the response (you do have a timeout).
2. But the IP layer doesn't use pigeons. You packet first needs to go out of your home network. Your IP layer doesn't know how. This is where MAC addresses come into picture.
3. Your link layer will talk to other link layers figure out how to dispatch the packet out of this subnetwork by using a protocol (language) called ARP. This is done via "Who has <IP Address>?" kind of a packet.
4. One you know how to get out of this subnetwork (you figure your gateway) you'll hand over your packet through the link layer again to that particular host.
5. There are intermediate hosts called routers which will try to move your packets from your gateway to Google's server. And finally the packet passes from Google's web server's link layer to IP layer. Then the web server's IP layer figures out which service to give the packet to and finally gives the packet to port 80 listening there.
6. And finally the response comes back similarly.

* Step 3 is not done everytime. Once you figure out who's who (MAC address to IP mapping) you cache them and use it instead.