Today, I learned about APR. Last time, I learned about the LAN address. As this picture described, each LAN has a unique MAC address. Here is the question: How to determine interface's MAC address, knowing its IP address? The Answer is "Refer to APR table." This is the APR table, which we can see on our cmd or terminal. We should know that how APR protocol works in network. Let's have an example..
When we learn about the network, we can see there are two address: IP address and MAC address. So, what is difference between them? ๐ญ IP address: IP address function: It is used globally on the internet to transfer packets from source node to remote destination. Network layer(layer 3) address for node/router interfaces. 32 bit IPv4 address assigned by DHCP server. MAC address (or LAN or physical..
Today, I leanred about the NAT: network address translation. Why there is a NAT in the real world?? Motivation: what is the problem? Number of IP addresses required in the internet is much more than the 4 billion available IP addresses. If a subnet grows larger than the ISP's IP address range, no IP address will be available for them. Solution: IPv6: larger IP address, more number of IP addresse..
Today, I learned about the DNS in Network programming class. So, What is DNS?? DNS stands for "Domain Name System." In real world, we identifies people with SSN, their name or passport number. Like this, our network server identifies with IP address and "name" like human. DNS is a distributed database. Implemented in a hierachy of many name servers. DNS is an application-layer protocol. Hosts an..
Today, I reviewed the HTTP connections. HTTP connections Non-persistent HTTP At most one object sent over TCP connection connection then closed Downloading multiple objects required mutiple connections Persistent HTTP Multiple objects can be sent over single TCP connection between client, server. Here is the picture describing Non-persistent HTTP And this is the Persistent HTTP. In the Web serve..
This time we are gonna talk about the Web and HTTP. Review: Web page consists of objects Object can be HTML, JPEG image, Java applet, audio file... Web page consists of base HTML-file which includes severall referenced objects Each object is addressable by a URL ex) www.someschool.edu(host name)/someDept/pic.gif(path name) HTTP: Hypertext transfer protocol Web's application layer protocol Client..
Today, I reviewed the HTTP in network programming. Creating a network app Write programs that: run on (different) end systems communicate over network e.g., web server software communicates with browser software No need to write software for network-core devices network-core devices do not run user applications applications on end systems allows for rapid app development, propagation. I need to ..
Today, I learned about the IP fragmentation and reassembly. So, our network usually have MTU (Max Transimission Unit): maximum amount of data that a link-layer frame can carry (max size of an IP packet). Different data link protocols (like Ethernet, WiFi) have different MTUs. The important point is that if a IP packet arrives at a router with larger size of packet than MTU, then the router divid..
Today, I learend about the Internet Protocol. It is the introduction part for IP Protocol. Before start the IP, we should know about the Network Layer. Network layer Transport segment from sending to receiving host On sending side encapsulates segments into datagrams On receiving side, delivers segments to transport layer Network layer protocols in every host, router Router examines header field..
How to assign an IP address to a host? 1. Manually: hard-coded by system admin in a file Windows: control-panel -> networking -> configuration -> TCP/IP -> properties. UNIX: /etc/rc.config 2. Automatically: DHCP: Dynamic Host Configuration Protocol DHCP is a plug and play protocol: a node can dynamically obtain an IP address when joining the network and release the IP address when leaving the ne..
