A blog on Cisco Certified Network Associate (CCNA) covering all the objectives found in the exam. Cisco Certified Network Associate (CCNA) Routing and Switching is the first step in gaining an understanding of how network engineers (or related jobs) function in a company.
CCNA Routing and Switching can be a:
2-part exam namely ICND1 and ICND2 which will earn you the CCENT certification.
or, the 1 part and more comprehensive 200-120 composite exam CCNAX which will earn you the CCNA certification.
After this one can take specialization such as CCNA-Voice, CCNA-Security or CCNA-Wireless or head straight to Cisco Certified Network Professional (CCNP) Routing and Switching which is composed of three parts namely: Route, Switch and Troubleshoot. After passing CCNP the expert level exam to be taken next is the Cisco Certified Internetwork Expert (CCIE) Routing and Switching which is regarded in the networking industry as the top level certification. One can also take other specialization depending on the person’s interest/passion or the need of the local job market.
ELEMENTS OF A GOOD NETWORK DESIGN
- Cost – should be cost-effective, meaning “sulit” or no money is wasted and effective and productive in relation to its cost.
- Speed- can be divided into Ethernet speeds:
Ethernet = 10 Mbps
Fast Ethernet = 100 Mbps
Gigabit Ethernet = 1000 Mbps = 1 Gbps;
Wide Area Network (WAN)
T1 = 1.544 Mbps = price (~20k php)
E1 = 2.048 Mbps = price (~40k php)
T3 = 45 Mbps = price (~100k php)
Committed Information Rate (CIR)
OC1 = 51 Mbps
OC2 = 102 Mbps
OC3 = 153 Mbps
- Availability – 99.99% uptime and should always be up. Measurement for network uptime:
Availability = [(Time Operating – Time Offline)/Time Operating] x 100 = %
= example: [(24-1)/24] x 100 = 99.993%
- Reliability – can be measured by:
Bandwidth = maximum speed
Throughput = Actual Speed = Bandwidth/ Number of Users
Latency = delay in the amount of time to receive or process a request. Uses ping to measure network delay. Total roundtrip time that is measured in milliseconds.
Best Quality of Service (QoS) is less than 200ms
Full Duplex- Transmit=Upload=Uplink
Auto-Negotiate- Fast speed connections becomes slow if paired with slow speed connections
- Local Area Network (LAN) = Etherchannel
- Wide Area Network (WAN) = Multilink
- Scalability – has room for expansion of modules/appliances. Small Form-factor Pluggable (SFP) Slots has expandable modules for Gigabit Mbps and Fiber Channels.
- Security – good security in software and hardware
- Topology – interconnection of network devices
Open Systems Interconnection (OSI) Layers
- Application Layer – any software/application that lets you connect to the network
- Presentation Layer – any file type that converts binar y data into human readable form
- Session Layer – controls the start and end of a network communication
- Transport Layer – reliable transport of Data and has error recovery. TCP/UDP
- Network Layer – Logical/IP Addressing. Path determination routing protocols such as RIP, EIGRP, OSPF, and BGP. Routers
- Data Link Layer – Physical/Mac Addressing and has error detection. WAN Encapsulation types includes PPP, HDLC, and Frame-Relay. Switches
- Physical Layer – Transmission mediums includes copper, fiber and air. Ethernet standards are TIA/EIA (Telecommunications Industry Association/ Electronics Industries Alliance). Connector Types: RJ-11, RJ-45, DB 9, RS 232
Encapsulation – Process of adding headers and trailers
De-encapsulation – process of removing headers and trailers