Monday, 30 April 2012

Procedure To Increase Swap File Under Linux

Type the following command to create 512MB swap file (1024 * 512MB = 524288 block size):

# dd if=/dev/zero of=/swapfile1 bs=1024 count=524288
  1. if=/dev/zero : Read from /dev/zero file. /dev/zero is a special file in that provides as many null characters to build storage file called /swapfile1.
  2. of=/swapfile1 : Read from /dev/zero write stoage file to /swapfile1.
  3. bs=1024 : Read and write 1024 BYTES bytes at a time.
  4. count=524288 : Copy only 523288 BLOCKS input blocks.
Type the following command to set up a Linux swap area in a file:
 
# mkswap /swapfile1

Setup correct file permission for security reasons, enter:
 
# chown root:root /swapfile1
 

# chmod 0600 /swapfile1

# swapon /swapfile1

To activate /swapfile1 after Linux system reboot, add entry to /etc/fstab file. Open this file using a text editor such as vi:
 
# vi /etc/fstab

Append the following line:
 
/swapfile1 swap swap defaults 0 0

Save and close the file. Next time Linux comes up after reboot, it enables the new swap file for you automatically.
Simply use the free command for Verify:

$ free -m

Wednesday, 7 March 2012

Learning about SS7 and SIGTRAN protocols...

SCTP - A TCP like protocol for reliable transportation between two signaling nodes
M3UA - Provides Network Routing between SS7 signaling nodes identified by Point Codes
SCCP - Provides Network Routing between SS7 signaling end points identified based on Global Titles (phone numbers can be used here)
TCAP - Manages end to end transactions between two nodes including time outs when peers don't respond
MAP - Presentation layer defining message formats and parameters for specific GSM / UMTS services e.g. Forward SMS
INAP/CAP - Similar to MAP except for IN or CAMEL services
IS-41 - Similar to MAP except an ANSI variant