Friday, 20 July 2012

Addresses on L2

Multicast addresses: Multicast addresses are used to allow a subset of devices on a
LAN to communicate. When IP multicasts over an Ethernet, the multicast MAC
addresses used by IP follow this format: 0100.5exx.xxxx, where any value can be used
in the last half of the address.

Sunday, 8 July 2012

Tuesday, 3 July 2012

CCNA Video in Hindi

http://www.youtube.com/playlist?list=PL3800FAC0F30CE3A6&feature=plpp

Wednesday, 22 February 2012

Three Switch Function at Layer 2

Address learning: L2 switches & bridges remembers the source hardware address of each frame received on an interface & they enter this information into MAC address table.

Forward/filter decision: When frame is received on an interface, the switch looks at destination hardware address & find exit interface in the MAC table. The frame is only forwarded out the specified destination port.

Loop avoidance: If multiple connections between switches are created for redundancy, network loop can occur, then STP is used.

Monday, 20 February 2012

SFP

The small form-factor pluggable (SFP) or Mini-GBIC is a compact, hot-pluggable transceiver used for both telecommunication and data communications applications. It interfaces a network device mother board (for a switch, router, media converter or similar device) to a fiber optic or copper networking cable. It is a popular industry format jointly developed and supported by many network component vendors.[1] SFP transceivers are designed to support SONET, Gigabit Ethernet, Fibre Channel, and other communications standards.

Monday, 13 February 2012

Quote

“Competition in [worldly] increase diverts you, until you visit the graveyards,” (Qur’an 102:1-2).

Wednesday, 8 February 2012

What is firmware and what part does it play in the boot process?

Firmware can be thought of as a combination of hardware and software. ROM (Read Only Memory) is an
example of firmware where we have software, or code, embedded on a memory chip. The memory is nonvolatile,
meaning the information does not go away once the computer is turned off.
Firmware, specifically ROM BIOS, plays a crucial role in the boot process since it contains much of the low level
operating instructions that enable the PC to boot properly. Occasionally when new peripherals are introduced
systems’ BIOS will need to be upgraded in order to recognize the new component.