Time flies!

 In a blink of an eye, So many things have happened. I couldn’t believe I can achieve most of my goals. Bought a house, and saved enough for traveling and saved enough amount to allow me to slow down my pace a bit. 

I changed a few jobs even though I love my jobs and the people in all my jobs, I always try not to get too involved as I will not bears to leave the places and people behind. Sometimes I don’t even understand why I choose to go and seek someplace where they offer a higher salary. Money is always not everything since I left the banking industry many years back and took up an IT job. Maybe the surrounding and the culture make me change my mindset when I am not thinking clearly.

I am still doing what I love, helping people around me like serving the community during the Covid period and doing volunteering by disturbing food. also returning back to help out in the pharmacy clinic after office hours. I committed too much of my time and overlook to contact most of my friends and family member.  Sadly few of my close family and friend all passed away. I attended and organized most of the funerals and I am so regretful that I didn’t spend more time with them. 

Our time is always invaluable that we can't purchase back, we're only here on earth for a brief lifetime and no matter how much money we have won't buy us more time than anyone else. for this, I have decided to drop some of the things I am doing now and focus on other aspects. I am so sorry that I can't help as I need to heal myself.

To end this, cherish those you think are kind people and treat you back the way you always wanted, because those people are hard to come by as you get older. Cheers and hope everyone is still doing well in 2023! 

First Post in 2016!

This will be a tough year as I set on many short term goals to achieve! I will try to accomplish it by this year! Good thing is I have fulfilled my goal in 2015 to earn and save up 100k! Overall is not about the money and I felt like it is a stupid goals that I have set for the last 2 year and doing thing that I have zero interest but to allow myself to do what I really want without any debt or borrowing from friend. I have finally left my position on banking and financial last year and pursue my career in what I studies during polytechnic and I have been in this field for almost 3month. Initially is hard but my colleague is nice to help me out. I will still need to improve myself more on this field as I know I am still not good enough at it.

Goals for this year!                                                             

• Get CCNA this year.
• Get driving license 
• Understand fully Stock Market 
• Backpack to try Travel alone! i alway really wanted to do this for a long time.

Press on!! 

Coursework ICND1/1

Problem 1

Identifying Collision and broadcast domain.

In the following exhibit, identify the number of collision domains and broadcast domains in each specifies device. Each device is represented by a letter:
A. Hub
B. Bridge
C. Switch
D. Router

A.  (Hub)

Diagram 1

Ans: 
BoardCast Domain : 1
Collision Domain : 1

Diagram 2

Ans: 
BoardCast Domain : 1
Collision Domain : 1

Diagram 3

Note: Entire Hub is a collision Domain.

Without a router connected, broadcast Domain will away remain as 1

Ans: 
BoardCast Domain : 1
Collision Domain : 1

---

B. (Bridge)

Diagram 1

Note: Entire Hub is a collision Domain.

Ans: 
BoardCast Domain : 1
Collision Domain : 2

---

C. (Switch)

Diagram 1

Note: every port used on the switch is a collision

Ans: 
BoardCast Domain : 1
Collision Domain : 3

Diagram 2

Note: 3 PC connected to the switch created 3 collision and entire hub connected to the switch belong to 1 single collision

Ans: 
BoardCast Domain : 1
Collision Domain : 4

---

D. (Router) 

                                                                      Diagram 1

*Router do not allow Broadcast domain and multicast to go through! 

* Without a router connected, broadcast Domain will away remain as 1 but with router , it have created 3 broadcast domain. Every port used on the router create a broadcast domain.  Note: Entire Hub is a collision Domain.

Ans: 
BoardCast Domain : 3
Collision Domain : 3

Diagram 2

For switch ,every port that is been used is a collision domain. Switch and Hub connected to the router have created two more collision domain.  Note: Entire Hub is a collision Domain.

Ans: 
BoardCast Domain : 2
Collision Domain : 5

Diagram 3

Ans: 
BoardCast Domain : 2
Collision Domain : 7

---

Problem 2

Convert the following from binary format to decimal IP adddress.
Complete the following table to express 11001100.00110011.10101010.01010101 in decimal IP address format.

128       64       32       16       8       4       2       1       Decimal

Working: 

128		32		128		64
64		16		32		16
+         8		+         2		+         8		+         4
4		1		2		1
______		______		______		______
204		51		170		85

Ans: 204.51.170.85

Convert from decimal IP address to binary format.
Complete the following table to express 192.168.10.15 in binary format.

128       64       32       16       8       4       2       1       Decimal

Working: 

 192(base10) = 1100 0000 (base 2)
 168(base10) = 1010 1000 (base 2)
 10  (base10) = 0000 1010 (base 2)
 15  (base10) = 0000 1111 (base 2)

Ans: 1100 0000. 1010 1000. 0000 1010. 0000 1111

---

Problem 3

Given the following IP address and subnet mask determine thier respective Network ID and HostID
1) 212.100.200.123
    255.255.255.0

Ans:

	Network ID			Host ID
	212.	100.	200.	123
AND	255.	255.	255.	0
Net ID	212.	100.	200.	0
Host ID	0.	0.	0.	123

Step 1: Draw a vertical line before the 0 on subnet mask. everything before the 0 on subnet mask belong to Network ID and everything on the 0 onward will belong to Host ID
Step 2: in order to get Net ID we use 212 and AND (logic gates) with 255.
255 in binary code is 1111 1111(base 2) and 212 in binary code will be 11010100 (base 2). note: if you can remember clearly everything multiply with 255 will result in same number.

   1101 0100

     x        1111 1111

               1101 0100

Then do the same on the rest at only Network ID .

Network ID
	212.	100.	200.
AND	255.	255.	255.
Net ID	212.	100.	200.

Do take note not to multiply anything on the Host ID portion , i know 123 AND with 0 will result in zero. But to get the Net ID you only do multiply on Network ID portion and the rest will be just zero.

	Network ID			Host ID
	212.	100.	200.	123
AND	255.	255.	255.	0
Net ID	212.	100.	200.	0←

Step 3: to get the Host ID it is even more simple. on the Network ID portion it will alway be zero.

Network ID
	212.	100.	200.
AND	255.	255.	255.

Host ID

0.

0.

0.

then on the Host ID portion you just copy everything down or i can simply say it you OR (logic gates) it. 123 + 0 = 123.

	Network ID			Host ID
	212.	100.	200.	123
AND	255.	255.	255.	0
Host ID	0.	0.	0.	123←

2)183.6.45.124

    255.255.0.0 

	Network ID		Host ID
	183.	6.	45.	124
	255.	255.	0.	0
Net ID	183.	6.	0.	0
Host ID	0.	0.	45.	124

3} 12.205.3.224

     255.0.0.0

	Network ID	Host ID
	12.	205.	3.	224
	255.	0.	0.	0
Net ID	12.	0.	0.	0
Host ID	0.	205.	3.	224

I have been working in this particular company for 6 month introduce by my friend after my graduation , how time flies! Due to restriction i am only allowed to post non specific detail, not even my company name! i am working in the Finance Field as a sales executive which have no related to what i had studied in poly. My job is to put myself in this competitive sales and marketing field which i find it very stressful and mentally tired. but everyday i keep remind myself that I have nothing to lose and everything to gain. This help me keep on going when i think i cant.

I need to work almost 7 days a week as we need to focus on sales especially on weekend which attract the most crowd. i find i have so little time for myself and sometime I wish I hadn't worked so hard. i rememeber at the start of the few days of my work i told my friend (who introduce me into this job) that i find this job is very stressful and no prospect, in the first place this is no a working environment i wanted. he replied me that cost of living in Singapore is very high and inflation keep on rising. he said i can choose to work in the office and a basic salary of $1600 - $1800 or choose to work harder here to use this sum of money to do what i want later on.

there will be no more post regarding scl stuff. i have graduated last year

Failed my M9 exam the second time, working full time and studying at the same time are really hard to manage. hope i am able to pass on the 3rd time.

Glossary

The following are some common terms you might come across during this 3 year, it is used for easy reference only.

Term	DEFINITION
10BaseT	This is one of several adaptions of Ethernet (IEEE 802.3) standard for Local Area Networks(LANs). The 10Base-T standard (also called Twisted Pair Ethernet) uses a twisted-pair cable with maximum lengths of 100 meters. Cables in 10Base-T system connect with     RJ-45 connectors. A star topology is common with 12 or more computers connected directly to a hub or concentrator. Also see Ethernet, LAN and RJ-45 connectors.
Bandwidth	The amount of data that can be transmitted in a fixed amount of time. For digital devices , the bandwidth is usually expressed in bits per second (dps) or bytes per second. For analog devices, the bandwidth is expressed in cycles per second, or Hertz (Hz).
Cache	A cache stores recently used information in a place where it can be accessed extremely fast. For example, a web browser like Netscape Navigator uses a cache to store on your hard drive the pages, images, sounds and URLs of web sites you visit. This means that everything doesn't have to be downloaded to your computer all over again when you visit the page again. Because accessing your computer's hard disk is much faster than accessing the internet, this speeds up web browsing significantly.
Data transfer rate	Alsio known as throughput, this is the speed with which data can be transmitted from one device to another. Data rates are often measured in megabits(Mbps) or megabytes (MBps) per second. DHCP Short for Dynamic Host Configuration Protocol, it is a protocol for assigning dynamic IP addresses to devices on a network. with dynamic addressing, a device can have a different IP address every time it connects to the network. Also see IP address.
DNS	This is short for Domain Name System (or Service). Every time you use a domain name, a DNS service must translate the name into corresponding IP address. For example, the domain name www.sp.edu.sg might translate to 192.168.42.129. Also see Domain Name and IP Address. <you can check the Domain Name by using NSlookup at the command prompt>
DOCSIS/ DOCSIS-compliant	Developed bby CableLabs and approved by ITU in march 1998, Data Over Cable Service Interface Specification (DOCSIS) defines interface standards complaint for cable modems and supporting equipment, With certification from CableLabs, manufacturers will be able to produce cable modems for retail, so consumers no longer have to depend on leased cable modems from thier cable providers.
Domain name	A name that identifies one or more IP address. For example, the domain name microsoft.com represents about a dozen IP addresses. Domain names are used in URLs to identify particular Web pages. For example, in the URL http://www.sp.edu.sg, the domain name is SP.EDU.SG. Also see DNS and IP address. <you can check the domain name by accessing to this website http://www.checkdomain.com/>
Downstream Channel	A downsteam channle is one used to transmit signals from the headend to the user.
Ethernet	Ethernet is the most common type of connection computers use in a local area network (LAN). the most widely used forms of Ethernet are called 10BaseT with data transfer speeds up to 10 mbps and 100BaseT with transfer speed to 100 mbps. Also see 10BaseT and LAN
Hop	An intermediate connection in a string of connections linking two network devices. On the internet, for example most data packets need to go through several routers before they reach thier final destination. Each time the packet is forwarded to the next router, a hop occurs. The more hops, the longer it takes for data to go from source to destination. You can see how many hops it takes to get to another internet host by using PING or traceroute utilities. Also see Ping and Traceroute.
Host	A computer system that is accessed by a user working at a remote location. The system that contains the data is called the host, while the computer at which the user sits is called the remote terminal
Hub	A common connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports. When a packet arrives at one port, it is copied to other ports so that all segments of the LAN can see all packets. Also see LAN
IMAP	Short for Interner Message Access Protocol, it is a protocol for retrieving e-mail messages. Like POP, IMAP uses SMTP for communications between the e-mail client and server. Also see POP and SMTP.
IP address	An identifier for a computer or device on a TCP/IP network. Networks using the TCP/IP protocol route messages based on the IP address of the destination. The format of an IP address is a 32-bit numeric address written as four number separated by periods. Each number can be zero to 255. For example 1.160.10.240 could be an IP address. Also see DHCP, DNS, Domain Name and TCP/IP
LAN / local	A computer network that spans a relatively small area. Most LANs are confined to a single building or area network group of buildings.
MAC	Short for Media Access Control address, it is a hardware address that uniquely identifies each node of an address network. In IEEE 802 network, the Data Link Contorl(DLC) layer of the OSI Reference Model is divided into two sublayers: the Logical Link Control (LLC) layer and the Media Access Control (MAC) layer. The MAC layer interfaces directly with the network media. Consequently, each different type of network media requires a different MAC layer. Also see 10BaseT and Ethernet.
Newsgroup	An on-line discussion group. To view and post messages to a newsgroup, you need a newsreader, a program that runs on your computer and connects you to a news server on the internet.
Ping	Short for Packet Internet Groper, it is a utility to determine whether a specific IP address is accessible. It works by sending a packet to the specified address and waiting for a reply. PING is used primarily to troubleshoot internet connections. Also see IP Address and Trace route.
POP	Short for Post Office Protocol, it is a protocol used for email service. Also see IMAP and SMTP.
Proxy server	A proxy server is a server (a computer system or an application) that acts as an intermediary for requests from clients seeking resources from other servers. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resource available from a different server and the proxy server evaluates the request as a way to simplify and control its complexity. Today, most proxies are web proxies, facilitating access to content on the World Wide Web.
RJ-45	Short for Registered Jack-45, it is an eight-wire connector used commonly to connect computers onto a local-area network (LAN), especially Ethernets. RJ-45 connectors look similar to the ubiquitous RJ-11 connectors used for connecting telephone equipment, but they are somehwat wider. Also see 10BaseT and Ethernet.
SMTP	Short for Simple Mail Tranfer Protocol, It  is a protocol for sending e-mail message between servers. Most email systems that send mail over the internet use SMTP to send messages form one server to another; the messages can then be retrieved with an e-mail client using either POP or IMAP. in addition, SMTP is generally  used to send messages from a mail client to a mail server. This is why you need to specify both the POP or IMAP server and the SMTP server when you configure your e-mail application. Also see POP and IMAP
TCP/IP	Short for Transmission Control Protocol/Internet Protocol, it is the suite of communications protocols used to connect hosts on the internet. TCP/IP uses several protocols, the two main ones being TCP and IP. TCP/IP is built into the UNIX operating system and is used by the internet, making it the de facto standard for transmitting data over networks.
Throughput	*See Data Transfer Rate
Traceroute	A utility that traces a packet fro your computer to an internet hotse, showing how many hops the packet requires to reach the host and how long each hop takes, if you're visiting a Web site and pages are apperaing slowly, you can use traceroute to figure out where the longest delays are occurring. Windows includes a traceroute utility called tracert. in windwos 95, you can run tracert by selecting Start->Run...cmd, and then entering tracert followed by the domian name of the host. For example: tracert www.sp.edu.sg. Also see Host and Hop
Upstream channel	an upstream channel is a frequency band that is used to send signal from the user to the headend.
USB	Short for Universal Serial Bus, it is a new external bus standard that supports data transfer rate of 12 Mbps (12million bits per second). USB also supports Pulg-and-Play installation and hot plugging. Also see Data Transfer Rate
UTP	Short for Unshielded Twisted Pair, a popular type of cable that consists of two unshielded wires twisted around each other. Due to its low cost, UTP cabling is used extensively for local-area network (LANs) and telephone connections.

ET0720 Advanced Microcontroller Techology