Network Connection

In order to understand the spec of the network card being used by your server:

lspci | grep -i net

Here, as example of the status on my job's cloud : 

ro -a -o . -h els2 -s shared -irc %/ lspci | grep -i net
[ virginia / svpr-els204 ] - 03:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)        <<== which means 1 GB only
[ virginia / svpr-els204 ] - 03:00.1 Ethernet controller: Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)
[ virginia / svpr-els204 ] - 03:00.2 Ethernet controller: Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)
[ virginia / svpr-els204 ] - 03:00.3 Ethernet controller: Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)
[ virginia / svpr-els205 ] - 03:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)
[ virginia / svpr-els205 ] - 03:00.1 Ethernet controller: Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)
[ virginia / svpr-els205 ] - 03:00.2 Ethernet controller: Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)
[ virginia / svpr-els205 ] - 03:00.3 Ethernet controller: Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)
[ virginia / svpr-els206 ] - 03:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)
[ virginia / svpr-els206 ] - 03:00.1 Ethernet controller: Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)
[ virginia / svpr-els206 ] - 03:00.2 Ethernet controller: Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)
[ virginia / svpr-els206 ] - 03:00.3 Ethernet controller: Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)
[ virginia / svpr-els207 ] - 04:00.0 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)             <<== this means the card is 10Gb/sec 
[ virginia / svpr-els207 ] - 04:00.1 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)
[ virginia / svpr-els208 ] - 04:00.0 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)
[ virginia / svpr-els208 ] - 04:00.1 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)
[ virginia / svpr-els209 ] - 04:00.0 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)
[ virginia / svpr-els209 ] - 04:00.1 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)
[ virginia / svpr-els21 ] - 04:00.0 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)
[ virginia / svpr-els21 ] - 04:00.1 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)
[ virginia / svpr-els210 ] - 04:00.0 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)
[ virginia / svpr-els210 ] - 04:00.1 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)
[ virginia / svpr-els211 ] - 04:00.0 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)
[ virginia / svpr-els211 ] - 04:00.1 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)
[ virginia / svpr-els212 ] - 04:00.0 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)
[ virginia / svpr-els212 ] - 04:00.1 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)
[ virginia / svpr-els22 ] - 04:00.0 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)
[ virginia / svpr-els22 ] - 04:00.1 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev 01)

In addition, in order to understand the SWAP memory usage :

free -g 

 free -g             total       used       free     shared    buffers     cachedMem:           125        110         15          0          3         67-/+ buffers/cache:         39         86Swap:          128          0        128

==> Means that the OS has about 67+15 GB available

If you don't want to use swap (it may slow your server/application etc) 

• swapoff -a   ==> do never use swap
• sysctl vm.swappiness=0   ==> use swap only if you don't have any more choice
• sysctl vm.swappiness=60   ==> use swap only if you reach more than 60% of the memory
• swapon -a ==> enable usage of SWAP, according to the swappiness value 
•  sysctl -a |grep swap  : to understand what is the % policy value.

Using top, you can have the following:

Mem:  132119828k total, 131341592k used,   778236k free,  3505520k buffers

Swap: 134365176k total,    88752k used, 134276424k free, 105451036k cached  <<== this is the FULL RAM available

More info regarding swap can be found: 

http://askubuntu.com/questions/103915/how-do-i-configure-swappiness