About Network Storage

Difference Between SAN vs NAS

Both Storage Area Network (SAN) and Network Attached Storage (NAS) provide  network storage solutions.

A NAS is a single storage device that operate on data files, while a SAN is a local network of multiple devices that operate on disk blocks.

SAN vs NAS Technology

A SAN commonly utilizes Fiber Channel interconnects. A NAS typically makes Ethernet & TCP/IP connections.

SAN vs NAS Usage Model

The administrator of a home or small business network can connect one NAS device to their LAN.

The NAS maintains its own IP adress comparable to computer and other TCP/IP devices. Using a software program that normally is provided together with the NAS hardware,  a network administrator can set up automatic or manual backups and file copies between the NAS and all other connected devices. The NAS holds many gigabytes of data, up to a few terabytes. Administrators add more storage capacity to their network by installing additional NAS devices, although each NAS operates independently.

Administrators of larger enterprise networks may require many terabytes of centralized file storage or very high-speed file transfer operations. Where installing an army of many NAS devices is not a practical option, administrators can instead install a single SAN containing a high-performance disk array to provide the needed scalability and performance. Administrators require specialized knowledge and training to configure and maintain SANs.

SAN / NAS Convergence

As Internet technologies like TCP/IP and Ethernet have proliferated worldwide, some SAN products are making the transition from Fibre Channel to the same IP-based approach NAS uses. Also, with the rapid improvements in disk storage technology, today's NAS devices now offer capacities and performance that once were only possible with SAN. These two industry factors have led to a partial convergence of NAS and SAN approaches to network storage.

About Storage

Difference between SATA I, SATA II and SATA III

What is the difference between SATA I, SATA II and SATA III?

SATA I (revision 1.x) interface, formally known as SATA 1.5Gb/s, is the first generation SATA interface running at 1.5 Gb/s. The bandwidth throughput, which is supported by the interface, is up to 150MB/s.

SATA II (revision 2.x) interface, formally known as SATA 3Gb/s, is a second generation SATA interface running at 3.0 Gb/s. The bandwidth throughput, which is supported by the interface, is up to 300MB/s.

SATA III (revision 3.x) interface, formally known as SATA 6Gb/s, is a third generation SATA interface running at 6.0Gb/s. The bandwidth throughput, which is supported by the interface, is up to 600MB/s. This interface is backwards compatible with SATA 3 Gb/s interface.

SATA II specifications provide backward compatibility to function on SATA I ports. SATA III specifications provide backward compatibility to function on SATA I and SATA II ports. However, the maximum speed of the drive will be slower due to the lower speed limitations of the port.

Example: SanDisk Extreme SSD, which supports SATA 6Gb/s interface and when connected to SATA 6Gb/s port, can reach up to550/520MB/s sequential read and sequential write speed rates respectively. However, when the drive is connected to SATA 3 Gb/s port, it can reach up to 285/275MB/s sequential read and sequential write speed rates respectively.

NAS Configuration

Further to the article about the best practices to organize your media collection, we will go deeper into the world of media storage servers.

Have you ever wondered of creating a file server to link multiple TV’s and to store all the media into a centralized server (as opposed to a dedicated hard drive). In this complete guide, I will cover the steps needed to setup your own Network Attached Storage (NAS server) to store all your media files in a cloud.

What is NAS?

NAS is your personal media cloud

NAS (Network Attached Storage) is an abbreviation of the term network attached storage, which is a storage that can be accessed over a home network as opposed to a single computer access. In other words, a NAS server allows you to share media files between several computers and portable entertainment devices.

Additional benefit is that NAS servers often include multiple hard drives which allows you to backup and mirror data between multiple hard drives.

So, let’s get started with the following 7 steps to setup your own media cloud.

1. Get a network attached storage and hard drives

There are several sharing NAS devices available in the market with different speeds and set of features.Synology DiskStation 2-Bay Network Attached Storagehas been my favorite for couple of years and I currently own the DS209+ model (the latest model is DS212J).

If 2-Bay model is too little for your needs, you should check out the Drobo FS 5-Bay Storage Array which allows you to store up 10 TB of data.

2. Install the hard drives

Remember that most of the time the NAS servers do not include hard drives, so you need to buy them separately.

I recently replaced my old Seagate 1 TB hard drives with Western Digital 2 TB Caviar Green SATA II hard drives as one of the Seagate HDDs failed. This incident reinforced the importance to have at least two hard drives mirroring the data all the time.

Installing HDDs was very easy. I needed to unscrew couple of screws, connect the power cable and SATA II cable and put the screws back in place. In few minutes, I was ready the start the server again. Please note that my current model supports only SATA II HDDs, while the newer NAS servers support SATA III connection.

After installing the new hard drives, I noticed that the WD Caviar Greens are significantly quieter compared to my old Seagate HDDs.

3. Setup the RAID and format the volume

RAID is an abbreviation of the term Redundant Array of Independent Disks. RAID storage technology allows you to combine multiple hard drives together by distributing the data across multiple disks. There are several RAID levels depending on how many hard drives you have in use.

Here are the three common RAID levels:

RAID 0 allows you to have the maximum amount of storage, but you will not have backup for the data if one of your HDDs fails. For example, if you have two 2 TB drives, the total array size is 4TB and you will have 3.72 TB of usable storage.

RAID 1 allows you to mirror data between two hard drives, so if one HDD fails, you still have the data secured on the other drive. However, if you have two 2 TB drives, your total array size is only 2 TB and you will have will have 1.86 TB of usable storage.

RAID 5 stripes both data and parity information on three or more HDDs. It is very popular RAID level as it has relatively good performance level and it will work fine even if one hard drive fails in the array. If you have five 2 TB drives, your total array size is 8 TB and you will have 7.45 TB of usable storage.

In my 2-Bay server, I use the RAID 1 level as it provides much greater security compared to the RAID 0 even if I lose 2 TB of storage.

4. Create the media structure to the NAS drive

After you have formatted the volume, it is time to create folder structure and set user access rights to the folders. I chose to create separate folders for each media type such as Music, Photo and Video.

The additional folders include Backup and Documents folders for my desktop computer and Web folder for my Web server (local website development e.g. for this site).

You can read the complete guide here on how to manage your media files structure.

5. Copy media content to the NAS drive

Copying files can take even days

Now it is time to copy media files back to the network drive. Depending on your network speed and number of files, you should allow enough time for this step. It can easily take several hours, even days to complete this step. In my case, I had a temporary 1 TB copy on an external USB hard drive, where I stored all the files from the old 1 TB Seagate HDD.

6. Configure the NAS drive with the media center software

Once you have copied all the files to the NAS drive, it is time to configure it with the media center software. You can do the following steps in most popular media centers such as Windows Media Center, XBMC, Boxee, Plex and Media Portal.

I will use XBMC media center as an example on how to create a video folder share with the network drive.

• Select Video from the XBMC home menu
• In the files view, select “Add Source”
• Select Browse
• Scroll to the bottom of the list and select “Add Network Location…”
• Choose the “Protocol” as Windows Network (SMB)
• Type the “Server Name” on your home network e.g. 192.168.1.43
• Type the “Shared folder” on your NAS e.g. Video
• Type the “Username” and “Password” for the folder on your NAS
• Click OK two times

7. Synchronize you media software with NAS

Final step is to make sure that your media management software will update files automatically to the network drive.

I use Picasa to manage photos, so I changed the default folder as the one in the network storage. In iTunes, I deleted the old music library and imported a new library from the network storage. Remember to change the default saving folder to NAS as well.

What’s next?

Congratulations, now you are ready to enjoy your Network Attached Storage over the home network. Next, try to access media files with your iPad, iPhone or Android mobile phone to enjoy the benefits of having a personal media cloud.

If you feel that the network speed is too slow e.g. to play HD videos over the network, continue reading this guide on how to stream Blu-ray movies over the home network.

About CME

Introduction

This document covers the Configuration steps to Implement After-Hours Call blocking on Cisco Unified Communications Manager Express (CME). After-hours call blocking helps the user to block specific calls which are placed after the working hours.After-hours blocking can also be used to restrict calls to numbers/area codes known as fraudulent calling patterns.

What is After-Hours Call blocking and Why it is required ?

There have been may recorded incidents of business phone calls being placed After-hours, when staff has left for the evening. To prevent this you can implement After-hours call blocking on CME

After-Hours call blocking allows you to define ranges of times specified as After-hours intervals. User has an option to list number patterns that are not allowed during those intervals. If any user places a call during the After-hours time range that matches one of the defined patterns, CME will play a tone and disconnect the call.

After-hours call blocking has three major steps of configuration

Step1 : Define days and/or hours of the day that your company considers off-hours.

Step2 : Specify the patterns that you want to bock during the time specified as off-hours.

Step3 : Create exemptions to the policy, if needed.

Configure the After-Hours call blocking from telephony-service configuration mode.

Note:-

There are some patterns that may be benificial to block all the time. Say 1-900 numbers are always high-cost and needs to be blocked at all the times. CME allows you to create a 24/7 non exemptible patterns that is disallowed at all the times using After-hours call blocking system.

After-Hours Configuration Examples

1. Configuring After-Hours call blocking for specific Time-Ranges

Configuration Example

CME_Router(Config) # telephony-service CME_Router(Config-telephony)# after-hours day mon 18:00 8:00 ! -- day - define day in week ! -- hh:mm - Time to start and stop CME_Router(Config-telephony)# after-hours day mon 18:00 8:00 CME_Router(Config-telephony)# after-hours day tue 18:00 8:00 CME_Router(Config-telephony)# after-hours day wed 18:00 8:00 CME_Router(Config-telephony)# after-hours day thu 18:00 8:00 CME_Router(Config-telephony)# after-hours day fri 18:00 8:00

2. Configuring After-Hours call blocking for specific Date/Holiday

Configuration Example
Implementing After-hours call blocking for the entire day dec 25 (Christmas) and jan 1 (New year) CME_Router(Config-telephony)# after-hours date dec 25 00:00 00:00 CME_Router(Config-telephony)# after-hours date jan 1 00:00 00:00

3. Configuring After-Hours Block Patterns

Configuration Example
Define the block patterns that CME should block during the After-Hours configured in Sample configuration - 1 CME_Router(Config) # telephony-service CME_Router(Config-telephony)# after-hours block pattern 1 91........ CME_Router(Config-telephony)# after-hours block pattern 2 9011T

4. Block specific call patterns for 24/7

Configuration Example
CME_Router(Config-telephony)# after-hours block pattern 3 91900........ 7-24 ! -- 7-24 block pattern works fof 7*24. This syntax tells the CME to block calls to this pattern at all the times

5. Configuring After-hours Exemption

Configuration Example

Configure ephone1 to exempt from the After-hours call blocking policy CME_Router(Config)# ephone 1 CME_Router(Config)# after-hour exempt CME_Router(Config)# exit ephone 2 is configured with PIN to exempt from the After-hours call blocking policy CME_Router(Config)# ephone 2 CME_Router(Config)# pin 5555 ! -- pin - pin number can be any number between four-eight digits. CME_Router(Config)# exit CME_Router(Config)# telephony-service CME_Router(Config-telephony)# login timeout 120 clear 23:00

 

Verifying Call Blocking Configuration

Step 1 Use the show running-config command to display an entire configuration, including call-blocking number patterns and time periods and the phones that are marked as exempt from call blocking.

telephony-service

fxo hook-flash

load 7960-7940 P00305000600

load 7914 S00103020002

max-ephones 100

max-dn 500

ip source-address 10.115.43.121 port 2000

timeouts ringing 10

voicemail 7189

max-conferences 8 gain -6

moh music-on-hold.au

web admin system name sys3 password sys3

dn-webedit

time-webedit

transfer-system full-consult

transfer-pattern .T

secondary-dialtone 9

after-hours block pattern 1 91900 7-24

after-hours block pattern 2 9976 7-24

after-hours block pattern 3 9011 7-24

after-hours block pattern 4 91...976.... 7-24

!

create cnf-files version-stamp 7960 Jul 13 2004 03:39:28

Step 2 Use the show ephone login command to display the login status of all phones.

Router# show ephone login

ephone 1 Pin enabled:TRUE Logged-in:FALSE

ephone 2 Pin enabled:FALSE

ephone 3 Pin enabled:FALSE

Step 3 The show voice register dial-peer command displays all the dial peers created dynamically by SIP phones that have registered, along with configurations for after hours blocking.

About PBX

What is a PBX Phone System?

PBX stands for Private Branch Exchange, which is a private telephone network used within a company. Users of the PBX phone system share a number of outside lines for making external phone calls.

A PBX connects the internal telephones within a business and also connects them to the public switched telephone network (PSTN), VoIP Providers and SIP Trunks.

One of the latest tendencies in PBX phone system development is the VoIP PBX, also known as IP PBX, which uses the Internet Protocol to transmit calls.

Nowadays, there are four different PBX phone system options:

·         PBX

·         Hosted/Virtual PBX

·         IP PBX

·         Hosted/Virtual IP PBX

IP PBX is a software-based PBX phone system solution which helps accomplish certain tasks and delivers services that can be difficult and costly to implement when using a traditional proprietary PABX.

3CX Phone System for Windows is a good example of an IP PBX phone system.

  

About Well-known Ports

Port 8080

Name:	HTTP
Port no:	80 and 81 or 8080
Description:	This port is a popular alternative to port 80 for offering web services. "8080" was chosen since it is "two 80's", and also because it is above the restricted well known service port range (ports 1-1023, see below). Its use in a URL requires an explicit "default port override" to request a web browser to connect to port 8080 rather than the http default of port 80. See the discussion of URL defaults and port overrides on the port 81 .

Name:	FTP Data and FTP control
Port no:	20 and 21
Description:	The File Transfer Protocol (FTP) is a standard network protocol used to transfer computer files from one host to another host over a TCP-based network, such as the internet. FTP is built on a client-server architecture and uses separate control and data connections between the client and the server.

Name:	SMTP
Port no:	25
Description:	SMTP (Simple Mail Transfer Protocol) is a TCP/IP protocol used in sending and receiving e-mail. However, since it is limited in its ability toqueue messages at the receiving end, it is usually used with one of two other protocols, POP3 or IMAP, that let the user save messages in a server mailbox and download them periodically from the server. In other words, users typically use a program that uses SMTP for sending e-mail and either POP3 or IMAP for receiving e-mail. On Unix-based systems, sendmail is the most widely-used SMTP server for e-mail. A commercial package, Sendmail, includes a POP3 server. Microsoft Exchange includes an SMTP server and can also be set up to include POP3 support. Many mail servers now support Extended Simple Mail Transfer Protocol (ESMTP), which allows multimedia files to be delivered as e-mail.