200-125 CCNA ( CCNAX => Cisco Certified Network Associate Accelerated )

Cisco Systems is a multinational company which deals with the design, manufactures and sells networking as well as inter-networking based devices.

Cisco sells a range of Products and Services, the detail is available online:
http://www.cisco.com/c/en/us/products/index.html

The persons working with Cisco devices can also have professional certifications from Entry to Architect level.

Cisco on its website has an Interactive Career Path. It is very helpful in choosing a specific training paths. Newcomers in the field of networking are highly recommended to follow the link bellow. The link covers all of the certification like  IT Essential: PC Hardware and Software, CCNA, CCNP, CCIA and CCAr.

http://www.cisco.com/web/learning/netacad/get_involved/careerPath.html

DIX (Digital, Intex, Xerox) jointly developed an standard in 1980 which defined a frame called DIX frame also called Ethernet_II frame.

IEEE started to work on Ethernet in February 1980, that's why it is called 802 (80 from 1980 and 2 from February).

Following are the various LAN standards.

IEEE standard Name	Media Type	Speed
10Base-T (IEEE 802.3)	category 3 unshielded twisted pair (UTP)	10Mbps
100Base-TX (IEEE 802.3u)	EIA/TIA category 5, 5E, or 6 UTP two-pair wiring	100Mbps
100Base-FX (IEEE 802.3u)	fiber cabling 62.5/125-micron multimode fiber	100Mbps
1000Base-CX (IEEE 802.3z)	Copper twisted-pair, called twinax	1Gbps
1000Base-T (IEEE 802.3ab)	Category 5, four-pair UTP	1Gbps
1000Base-SX (IEEE 802.3z)	multimode fiber-optic	1Gbps
1000Base-LX (IEEE 802.3z)	Single-mode fiber	1Gbps
1000Base-ZX (Cisco standard)	single-mode fiber-optic links	1Gbps
10GBase-T (802.3.an)	UTP cables (category 5e, 6, or 7 cables)	10Gbps

SUMMARIZATION/  SUMMARY ADDRESS/  SUPERNETING/  AGGREGATION:

In summary route or route summarization, a series of IP address are mapped to a single IP address.

 

PROCEDURE:

Step 1. Write all the given IP address in the binary format.

172.16.12.0/24	10101100  00010000  00001100  00000000	10101100  00010000  00000000  00000000
172.16.13.0/24	10101100  00010000  00001101  00000000
172.16.14.0/24	10101100  00010000  00001110  00000000
172.16.15.0/24	10101100  00010000  00001111  00000000

Step 2. Count the number of bits in common which in the above table happens to be till bit number                 22nd bits

Step 3. Write the summary address from the common bits found in Step 2. In the example given                     above  this address would be  10101100  00010000  00010001  00000000

            The  decimal equivalent will be 172.16.12.0

Step 4. Write the count of common bits in the end of Summary address formed in Step 3, which in                 the above case would be 172.16.12.0/22

Note: The example has been taken from http://www.ciscopress.com/
The following link can be used to find out summary address for IP ranges:

http://www.netmatics.net/FreeTools/IPv4SupernetTools/SupernetCalc

Total Number of CCIE in the world can be found at:

http://web.archive.org/web/20071027063416/http://www.cisco.com/web/learning/le3/ccie/certified_ccies/worldwide.html