Week 3 - Networking 1 Flashcards
What is a network?
“A network is a system that permits networked applications on different host to work together.”
What is web 1.0
Web application provider creates content. Read but no feedback.
What is web 2.0
User provides content to web app or in social r’ship. User provides feedback, info, review, comment, interact with each other.
Diff between switched networks and circuit based networks (& why dedicated networks are impractical)
Circuit switching establishes a connection and gives you reserved capacity between source and dest until the connection is terminated whether it is being used or not. Inefficient & Expensive.
Packet switching breaks (fragments) a message up into small segments and forwards each separately. Each packet can take a different path to dest and get reassembled by dest host.
Packet switching is more efficient use of trunk lines as it multiplexes multiple connections over the one line. Users only pay for what they use rather than the whole connection. Cct effective for voice traffic, not for bursty data (short bursts, long silences)
Analog vs Digital vs Binary
Binary – digital signal that has only two states (high/low, on/off, 1/0, T/F, Y/N)
Digital – a few states (2, 4, 8, 16, 32…) Can encode two or more states but is finite. The more states the harder to tell the difference. Circuit attenuation will affect signal.
Analog – analogous to voice signal, rises and falls smoothly in intensity btwn two values. Can be any value in btwn dependant on measrmnt instr. Eg.rise/fall smoothly in intensity corresponding with voice loudness.
Difference between The Internet and internet.
The Internet is the global Internet system and internet is a general term for any internet (multiple networks connected by routers) or the internet layer.
How a packet travels over many networks.
App on host wants to send message. Sent to transport layer which puts msg into packet. This will be same packet along the entire route from src to dest host.
Packet encapsulated into frame and forwarded to connected switch
Switch makes forwarding decision based on destination address (doesn’t know entire path only next sw)
At router frame is stripped, router reads hdr and makes a frwding decision, re-encap & sends on.
What is RFC?
Network Working Group created by multiple schools to come up with standards. Had no authority to create standards, calld them Request for Comments instead. NWG became IETF Intrnt Engineering Task Force.
What is DHCP?
Dynamic Host Configuration Protocol – assigns dynamic IP address and subnet mask, default router address and local DNS server.
What is DNS?
Domain Naming System. Mechanism to convert human-readable hostnames to/from IP addresses.
What is NAT?
It translates between internal and external IP addresses.
