Data Networks Basics

Data network basics

Data Network basics

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Data network basics

The ethernet history

- Ethernet is developed by XEROX company, (Palo Alto Research Center) in 1973 by Mr Robert Metcalfe.

Metcalfe’s law:

“The value of a network is proportional to the square of the users of the system”

After concepting ethernet Metcalfe started the 3Com company in 1979.

http://en.wikipedia.org/wiki/Image:Network_effect.png

http://en.wikipedia.org/wiki/Image:Network_effect.png

Data network basics

The OSI model

Layer 7 Application Contains functions for particular application services

Layer 6 Presentation Data encryption and data compression

Layer 5 Session Establishment, maintanance and termination of sessions

Layer 4 Transport Flow control and error correction

Layer 3 Network Addressing of messages and determination of routes

Layer 2 Data link Procedures and protocols for operating the communication lines

Layer 1 Physical Physical connection to network








Sending host Receiving host

Enc

apsu

latio

n

De-

enca

psul

atio

n

Data network basics

The OSI model

Data network basics

The OSI model








Data

Segment

Packet

Frame

Bits

Upper layer data

TCP header Upper layer data

IP header Data

MAC header Data FCS

100101101010100000000000

UDP header Upper layer data

Data network basics

The OSI model

Internet Aviom EtherSound CobraNet Dante


HTTP




TCP UDP


IP IP


Ethernet Ethernet Ethernet Ethernet


Copper/fiber Copper Copper Copper/fiber Copper/fiber

Data network basics

The Building blocks

Data network basics

The Building blocks, the NIC

- Network Interface Card

- OSI model layer 1 connection

- Consider a regular audio device as a NIC

- Each NIC has a unique OSI Layer 2 identifier, the MAC address

Data network basics

What is a MAC address ??

- MAC = Media Access Control

- A MAC address is an OSI model Layer 2 identifier

- A MAC address is world wide unique

- ID’s are given by the IEEE Standards Association

- ID’s can be checked:

http://standards.ieee.org/regauth/oui/index.shtml

Data network basics

What is a MAC address ??

General = XX.XX.XX.XX.XX.XX

In total 2566 = 281.474.976.710.656 addresses

Yamaha = 00.A0.DE.XX.XX.XX (2563 = 16,8 million options)

00-A0-DE-25-20-0A

By the way: rearth = 1,7x106m

so Aearth = 4πr2= 3,6x1013m2

Means: 2,8x1014/3,6x1013 = 7 MAC/m2

Data network basics

The Building blocks, the HUB

- A hub is a networking distribution unit in Layer 1 of OSI

- Incoming frames are sent to all ports

Frame

Source MAC

Destination MAC

Frame

Frame

Frame

HUB

1 2

3

4

Data network basics

The Building blocks, the L2 Switch

- A switch is an intelligent networking distribution unit in Layer 2 of OSI (MAC)

- The switch stores the MAC address/port combination into a MAC addres table. The so called “translation table”

- Switches can be unmanaged or managed

- Managed switches have different extra technology build in

- VLAN

- QoS

- Redundancy

Frame

Frame

Switch

1 2

3

4

1 MAC

2 MAC

3 MAC

4 MAC

Frame

Frame

Data network basics

What is an IP address ??

- IP = internet protocol

- An IP address is an OSI model Layer 3 identifier

- Some IP addresses are worldwide unique

- Some are not (private addresses i.e. 192.168.0.1)

IP: A.B.C.D Subnet: 255.255.255.000 Class C 256 hosts

IP: A.B.C.D Subnet: 255.255.000.000 Class B 2562=65536 hosts

IP: A.B.C.D Subnet: 255.000.000.000 Class A 2563=16777216 hosts

Data network basics

What is an IP address ??

- The private IP addresses:

IP: A.B.C.D Subnet: 255.255.255.000 Class C 256 hosts

IP: A.B.C.D Subnet: 255.255.000.000 Class B 2562=65536 hosts

IP: A.B.C.D Subnet: 255.000.000.000 Class A 2563=16777216 hosts

One special Class B network is the “link local” or “fallback range”. Device set to DHCP, but no DHCP server in the network. That is the range Dante devices use by default.

10.0.0.0 – 10.255.255.255 16.777.215 Host ID’s(1x2563)

1 Class A network

172.16.0.0 – 172.31.255.255 65.535 Host ID’s(2562)

16 Class B networks

192.168.0.0 – 192.168.255.255 256 Host ID’s(2561)

256 Class C networks

169.254.0.0 – 169.254.255.255 65.535 Host ID’s(2562)

1 Class B networks

Data network basics

About subnetworks , Classless Inter Domain Routing (CIDR)

Class CIP: 192.168.10.100 11000000 . 10101000 . 00001010 . 01100100Subnet: 255.255.255.0 11111111 . 11111111 . 11111111 . 00000000

In CIDR noted as: 192.168.10.100/24 Which leaves: 32-24=8 >28=256 hosts

Class BIP: 172.18.135.12 10101100 . 00010010 . 10000111 . 00001100Subnet: 255.255.0.0 11111111 . 11111111 . 00000000 . 00000000


“Supernetting”or “Classless Subnet Masks” IP: 192.168.24.12 11000000 . 10101000 . 00011000 . 00001100Subnet: 255.255.252.0 11111111 . 11111111 . 11111100 . 00000000


Data network basics

The Building blocks, the router

- A router is a networking distribution unit in Layer 3 of OSI

- A router interconnects two different networks

- Internet to ethernet

- Ethernet to ethernet

- VLAN to VLAN

Router

1 280.123.100.98 192.168.10.1

Data network basics

The Building blocks, the router

- The “router” you have at home.......

ROUTER SWITCH ACCESS POINT

T

WAN

Data network basics

The Building blocks, the L3 switch

- A L3 switch is basically a L2 switch with additional L3 features

L3 switch Router 1.1.1.0/24 10.0.0.0/24 10.0.1.0/24

10.0.2.0/24

10.0.3.0/24

Data network basics

Resumé:

The NIC

The HUB

The switch

The router

The cable

Data network basics

Resumé:

The MAC address

The IP address

53°37'42.42" N 9°53'4.77" E

Siemensstrasse 22 - 34 25462 Hamburg

Deutschland

Data network basics

Ethernet topology, P2P or “ad hoc”

+ Easy and quick to setup

+ Easy to troubleshoot

- Please note to use a crosscable. (Unless the machines use auto-MDIX ports)

Audio application examples:

- Analog

- AES/EBU

- MADI

Data network basics

Ethernet topology, diasychain

+ Easy and quick to setup

+ Easy programming

+ Easy to troubleshoot

- In case of broken cable, “worm behaviour”


- EtherSound

Data network basics

Ethernet topology, Star network

+ Easy installation, expansion

+ Good performance, reliable

- High capacity star

- Star switch is s.p.o.f.

-> Use switch instead of hub, otherwise it’s bus


- Dante

- CobraNet

Data network basics

Ethernet topology, Ring network

+ Easy installation, expansion

+ Good performance, reliable

- Needs extra technology to work


- ES100

- RockNet

- Optocore

Data network basics

Ethernet topology, Mesh network

+ Self reparing, reliable

- Many connections

- Very complex


- None! Or hardly any....

Data network basics

Some building blocks which are not really relevant to audio, but interesting........

The DNS - Domain Name Server

- Translates a name into an IP address

For example: 202.55.138.123 into www.yamahaproaudio.com

- Normally given by your ISP

- Public DNS 8.8.8.8 or 8.8.4.4 (google)

http://www.yamaha.com

Data network basics


The DHCP server - Dynamic Host Configuration Protocol

- The DHCP server sends IP configuration data after it gets a request from new host

- IP address

- DNS server

- Timeserver (NTP)

- Default gateway

- etc.....

- Different DHCP modes:

- Dynamic: A range of IP addresses is defined in the DHCP.

- Static Specific IP addresses are defined based on MAC addresses.

Data network basics


The Gateway - The machine in your local network that points to internet

- In most cases the gateway is the DHCP server

The Proxy - The proxyserver is an in between server that can act as a filter and request data on the clients behalf.

The firewall - A firewall regulates traffic between different networks

Data network basics


WiFi

- IEEE 802.11x or WLAN

- Different protocols:

- 802.11b 2,4GHz 11Mbps

- 802.11a 5,0GHz 54Mbps

- 802.11g 2,4GHz 54Mbps

- 802.11n 2,4 and 5 GHz up to 540Mbps (finished in 2008)

- It’s not suitable for professional audio applications! (except for some very special versions)

- Very suitable for laptop running control software, iPad/iPhone, VNC

Data network basics

WiFi channels

- RF spectrum around 2.4 GHz

- Same frequency as mobile phones, bluetooth, microwave and radar

- 13 5MHz wide available channels of in Europe (US:12, Japan:14)

- Due to interference use spreaded channels.(1-13, 1-6-13, 1-5-9-13, etc)

- Use a scanner (PC: inSSIDer MAC:WiFi Explorer)

Country Channel Number

Frequency (GHz)

USA, Europe, Asia, Japan. 1 2.412USA, Europe, Asia, Japan. 2 2.417USA, Europe, Asia, Japan. 3 2.422USA, Europe, Asia, Japan. 4 2.427USA, Europe, Asia, Japan. 5 2.432USA, Europe, Asia, Japan. 6 2.437USA, Europe, Asia, Japan. 7 2.442USA, Europe, Asia, Japan. 8 2.447USA, Europe, Asia, Japan. 9 2.452USA, Europe, Asia, Japan. 10 2.572USA, Europe, Asia, Japan. 11 2.462USA, Europe, Asia, Japan. 12 2.467

Europe, Japan 13 2.472Japan 14 2.484

Data network basics

WiFi security

- Standard WiFi routers and WAP’s are not protected.

- Browser access with password

- Ecryption (WEP, WPA, WPA2)

- MAC address based filtering

- switch to stealth mode (SSID (Service Set Identifier) not broadcasted)

Data Networks Basics

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