Quick Reference
Kompakte Übersicht aller wichtigen Definitionen und Strukturen
7.2 IP-Adressen
IPv4 (32 Bit)
192.168.1.1 / 255.255.255.0
• 4 Oktette (8 Bit) = 32 Bit total
• Netz-ID + Host-ID
• Hosts = 2^(32-CIDR) - 2
• Netz: Hosts = 0, Broadcast: Hosts = 1
IPv6 (128 Bit)
2001:7c0:8280:253::20
• 8 Blöcke à 16 Bit (Hex)
• 64b Global Routing + 16b Subnet + 64b IID
• :: komprimiert Null-Blöcke
Private IPv4-Bereiche
10.0.0.0/8Class A
172.16.0.0/12Class B
192.168.0.0/16Class C
169.254.0.0/16Link-Local
IPv6-Adressarten
2000::/3GUA (Global)
fe80::/64Link-Local
fc00::/7ULA (Privat)
::1/128Loopback
7.3 Schichtenmodelle
| OSI | TCP/IP | PDU | Protokolle |
|---|---|---|---|
| 7 Application | 4 Application | Data | HTTP, FTP, SMTP, MQTT, DHCP |
| 6 Presentation | TLS, SSL, ASCII, Unicode | ||
| 5 Session | NetBIOS, RPC | ||
| 4 Transport | 3 Transport | Segment, Datagram | TCP, UDP |
| 3 Network | 2 Internet | Packet | IP (v4, v6), ICMP |
| 2 Data Link 1 Physical |
1 Network Access | Frame, Bit | Ethernet, WiFi |
7.4 Header-Strukturen
Ethernet II (14 Bytes)
Dst MAC6 Bytes
Src MAC6 Bytes
Type2 Bytes
Type: 0x0800=IPv4, 0x86DD=IPv6
IPv4 Header (20B+)
Version(4b) + IHL(4b) + TOS(8b)
Total Length (16b) + ID (16b)
Flags(3b) + Fragment(13b)
TTL(8b) + Protocol(8b) + CS(16b)
Src IP (32b) + Dst IP (32b)
Protocol: 6=TCP, 17=UDP, 1=ICMP
IPv6 Header (40B)
Version(4b) + TC(8b) + FL(20b)
Payload Length (16b)
Next Header (8b) + Hop Limit (8b)
Src Address (128b)
Dst Address (128b)
Next: 6=TCP, 17=UDP, 58=ICMPv6
TCP Header (20B+)
Src Port (16b) + Dst Port (16b)
Seq Number (32b)
Ack Number (32b)
Offset(4b) + Res(6b) + Flags(6b)
Window(16b) + CS(16b) + Urg(16b)
Flags: SYN, ACK, FIN, RST, PSH, URG
UDP Header (8B)
Src Port (16b) + Dst Port (16b)
Length (16b) + Checksum (16b)
Minimaler Overhead, verbindungslos
MQTT Header
Control Byte (8b)
Remaining Length (var)
Type + Flags (Dup, QoS, Retain)
7.1 Routing
Routing-Tabelle
| Netzwerk | Maske | Next-Hop | Exit |
|---|---|---|---|
| 10.1.0.0 | /16 | * | Gi0/1 |
| 192.168.1.0 | /24 | 10.1.0.253 | Gi0/1 |
| 0.0.0.0 | /0 | 141.91.7.2 | Gi0/0 |
Longest-Prefix-Match
Bei mehreren passenden Routen wird die mit dem längsten Präfix (genaueste) gewählt:
/32Host (1 IP)
/24Subnetz (256 IPs)
/16Netz (65k IPs)
/0Default (alle IPs)
7.5 IoT-Protokolle
MQTT (Port 1883/8883)
Topic:
Wohnung/Wohnzimmer/Temp
Wildcards:
# = Multi-Level, + = Single-Level
QoS 0
At most once
QoS 1
At least once
QoS 2
Exactly once
HTTP (Port 80/443)
GET
POST
PUT
DELETE
2xx
Success
3xx
Redirect
4xx
Client Error
5xx
Server Error
200 OK, 301 Moved, 404 Not Found, 500 Error