Kommunikation in verteilten Anwendungen
kvanC, iCompetence, FHNW, Dozent: Simon Marcin, Unterrichtssprache: Englisch
kvanC, iCompetence, FHNW, Dozent: Simon Marcin, Unterrichtssprache: Englisch
Set of flashcards Details
| Flashcards | 62 |
|---|---|
| Language | Deutsch |
| Category | Computer Science |
| Level | University |
| Created / Updated | 13.01.2022 / 25.05.2024 |
| Weblink |
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IP: IPv4 Netmask: Suffix
The suffix identifies the host number within the prefix.
IP: IPv4 Netmask: two forms?
– either in the form of xxx.xxx.xxx.xxx or
– short / yy where yy is the number of subnet bits in the prefix
IP: Subnet size?
Different netmasks change the amount of maximal available clients in a network.
IP: Loopback Interface (Io)
– Is local to the device itself, almost always: 127.0.0.1
– A device can have >1 loopback interface
IP: ICMP stands for?
Internet Control Message Protocol
IP: ICMP: What does it do?
ICMP uses IP as transport protocol on OSI Layer 3 (network) devices en route, thus ICMP is on layer 4 (transport).
Every IP device must implement it.
IP: DNS (Domain Name System)
Client server application that resolves names into their IP addresses.
DNS is not encrypted and everybody on the network (or ISPs) know which sites you visit.
IP: Connection types
- Unicast
- Broadcast
- Multicast
- Anycast
TCP: Layer?
Layer 4 (transport)
TCP: Characteristics
A byte stream
in order and reliably
connection-oriented
Implements flow control and error control.
Faulty packets get discarded and are handled the same as lost packets.
Does not use full band width.
TCP: Header size? Overhead size?
Header: 32 bit
Ovehead: at least 20 bytes
IP: Connection on a host: define five-tuple
- Source IP
- Destination IP
- Source Port
- Destination Port
- Protocol e.g. TCP
TCP: 3-way handshake: SEQ
SEQ: Sequence number
Every transmitted byte of a connection is numbered.
TCP: 3-way handshake: ACK
The byte which is expected to be received next.
TCP: 3-way handshake: FIN
Finish flag: Connection in this direction can be closed
TCP: 3-way handshake: Explain it (SYN, ACK, FIN).
Client: SYN: “Do you wanna talk?”
Server: SYN/ACK:
“I acknowledge you wanting to talk to me. Do you want to talk to me too?” AND “Received all byes up to 100. I’m ready to receive 101 (payed forward).”
Client: ACK: “I received all bytes up to 300. I’m ready to receive 301 (payed forward).”
TCP: 3-way termination: Explain it (SYN, ACK, FIN).
Client: FIN: “I want to close the connection.”
Server: ACK, FIN: “I hear ya (101). I want to close the connection too.”
Client: ACK: “Alright, I hear ya (301)”.
TCP: Congestion Control
- Slow start
- Congestion Avoidance Additive Increase
- Congestion Detection Multiplicate Decrease
TCP: Define socket.
Interface (“glue”) between an app process and network.
Enables two applications to send/receive data between each other.
UDP: Layer?
Layer 4 (Transport)
UDP: Characteristics?
Fast delivery
Connection-less
8 bytes overhead (no handshake, no conn.)
No congestion or flow-control
Faulty packets cannot be detected on UDP level only on app level). → data sent too fast is lost.
UDP: Header size? Overhead size?
Header: 32 bit
Overhead: 8 Bytes
