Download Network Technology and the 5000 Series

TCP-IP Primer
Internet
David Cozens
Targets
• Have a basic understanding of Ethernet
network technology
• Be aware of how this technology is applied on
the 5000 series.
• Be aware of simple debug tools and
techniques to perform basic fault finding
Network Training - Underlying Technology
• Ethernet
• IP
• TCP
Ethernet
• Physical Ethernet
• MAC Addresses
• Ethernet and the 5000 series
Physical Ethernet
• 10baseT/100baseT - twisted pair
• 10baseT is a subset of the 100baseT
specification
– 100baseT equipment is backwards compatible
– You can cable 10baseT and 100baseT equipment
together and it will operate at 10Mbps
• 10 base 2 - coaxial
• Fibre standards
• 802.11 - wireless standards
MAC Addresses
• MAC addresses are fixed with particular pieces
of hardware - they cannot be changed - if you
change the hardware you change the number.
• The number is normally written
08:00:48:80:00:10
Ethernet on the 5000 Series
• We use 10baseT Ethernet.
– Green light on the connector TX
– Orange light on the connector RX
Hubs and Switches
Used to connect 10 base T devices together.
• Aides and Pitfalls
– Power
– Connection LED
– Uplink setting
– Utilization/collision LEDs
Ethernet (Revision)
• Physical Ethernet
• MAC Addresses
• Ethernet and the 5000 series
IP Address Classes
• Classes are defined by the most significant 4 bits of the
address
– Class A - 0xxx - 128 networks with 2M hosts
» 0.0.0.0 to 127.255.255.255
– Class B - 10xx - 16K networks with 64k hosts
» 128.0.0.0 to 191.255.255.255
– Class C - 110x - 2M networks with 256 hosts
» 192.0.0.0 to 223.255.255.255
– Class D - 1110 - Reserved for multicast
» 224.0.0.0 to 247.255.255.255
– Class E - 1111 - Reserved
» 248.0.0.0 to 255.255.255.255
Private Networks
• Some network addresses are reserved for
private networks not connected to the internet.
If you are setting up a standalone network use
these numbers.
– 10.0.0.0 - 10.255.255.255 (10/8 prefix)
– 172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
– 192.168.0.0 - 192.168.255.255 (192.168/16 prefix)
Subnet Mask and Network Numbers
• IP Addresses have two components. A network number and a node
number. The subnet mask logically ANDed with the IP address gives
the network number.
• The IP Address with the network number removed gives the node
number.
• Network numbers are usually written as the IP address of the
network with trailing 0 followed by a the number of bits set in the
subnet seperated by a /
eg 192.168.1.0/24 has 24 bits of network number and 8 bits for the node
number.
• If you need to use the AND function on the windows calculator!
Subnet Exercise
IP
192.168.100.18
Subnet
255.255.255.0
What is Network Number and node number?
Network Number 192.168.100/24
IP
Node number is 18
192.168.100.18
Subnet
255.255.255.240
What is Network Number and node number?
Network Number 192.168.100.16/28
Node number is 2
Static Addresses on NT
In the Control Panel, select Network, then protocols, then TCP/IP and then
properties
Static Addresses on Windows 2000
In the Control Panel, select Network and dial-up Connections, then select your
Local Area Connection, then Internet Protocol(TCP/IP), then properties and
properties again. It’s then similar to NT.
Static Addresses on the 5000 Series
Use the Network/Address menu
PING
Subnets and Gateways
• Why do we need Subnets?
– Logically segregate the network
– Minimize bandwidth used
• Gateways connect networks/subnets together
Routing
• When a node wants to talk to another if it is on the same
network it talks directly.
• If it is on a different network it talks to the gateway which
forwards (routes) the message on.
Default Gateway configuration
Tracing the route to another host (tracert)
Address Assignment
• Static Configuration
• BootP
• DHCP
BootP
At startup the following conversation happens between a BootP Client
and server.
Client
Server
Hello everyone, I have MAC
address 00-d0-b7-3e-b0-b3
what are my network
parameters?
Hello 00-d0-b7-3e-b0-b3 here is
you IP address, subnet mask,
default gateway, DNS Server etc.
BootP Configuration on 5000 Series
The BootP timeout is how long to wait for the server to
respond. It may need to be increased on a busy network,
or if the server is slow.
DHCP - Dynamic Host Configuration
Protocol
The following dialog goes on between client and server
Client
•
Hello everyone, I have MAC
address 00-d0-b7-3e-b0-b3
what are my network
parameters?
Server
Hello 00-d0-b7-3e-b0-b3 here is you IP
address, subnet mask, default gateway,
DNS Server etc. You may lease it for X
hours.
Hello server, Can I renew my lease.
Yes, have another X hours.
Hello server, Can I renew my lease.
Yes, have another X hours.
….
….
DHCP configuration on NT
In the Control Panel, select Network, then protocols, then TCP/IP and then
properties
IP - Internet Protocol (Revision)
• IP Address Classes
• Subnets
• Gateways
• BootP/DHCP
• Basic Routing
TCP - Transmission Control Protocol
• Connection Based
• Ports and Sockets
• Firewall Basics
TCP is Connection Based
• TCP - Transmission Control Protocol
Ports and Sockets
• Ports
– Think of our phone analogy - Ports are like phone extensions.
– Port Numbers are between 0 and 65535
• Sockets
– A socket is a two way communication channel established on a
particular port.
Firewalls and the 5000 Series
Firewalls at their simplest block connections one way or both
ways through the firewall for specific protocols or ports. To use
the 5000 series across a firewall the following ports must be
open.
For FTP ports 20 and 21 (the 5000 series does not support
passive mode)
For Bridge 1264 (and 50010 for trend review)
For Modbus TCP 502
If the product is configured to use DNS it must also be able to
communicate with the DNS server and PING the DNS server.
TCP - Transmission Control Protocol (Revision)
• Connection Based
• Ports and Sockets
• Firewall Basics
Whats in a Name?
hydra.eurotherm.co.uk
• Hostname
Domain Name
These are NOTHING to do with NT domains.
Domain Name Service (DNS)
• DNS servers provide a means of finding the name for an
address, or the address for a name.
• A server knows about its domain and servers in parent
and child domains.
• There are often more than one DNS servers for a
domain - both have the same information - it is so the
network will still operate if one fails.
DNS Setup on the 5000 Series
nslookup
• Tests lookups of names and numbers
Ipconfig and winipcfg
• Microsoft tools for showing network settings
• Also used to release and renew dhcp leases manually.
Other protocols in the TCP/IP suite
MODBUS
TCP
ARP ICMP DNS
UDP
http
TCP
IP
PPP
SLIP
Ethernet
FTP
Application
Presentation
Session
Transport
Network
Data Link
Physical
Modbus TCP
• The same Modbus data reliably transferred
over a TCP socket connection.
• Think of the socket connection like a complete
modbus serial bus.
• One Modbus TCP connection connects a
master device to a slave device and/or a
gateway.
• Upto 247 modbus nodes can be communicated
with over a single socket.
Modbus TCP and the 5000
• The 5000 can simultaneously be
– Slave to 4 Modbus TCP socket connections
– Master to 16 Modbus devices (Serial, TCP or a
mixture)
– If configured for serial master communications with
talk through enabled then it can act as a gateway to
up to 246 serial slaves.
– If configured as a serial slave it can still be a Slave to
4 Modbus TCP connections and master to 16
Modbus TCP devices.
Modbus TCP Socket Sharing on the 5000
• Used to Improve timeout
behaviour and reduce resource
usage.
– If we are talking to multiple serial
slaves attached to a gateway they all
share the serial bus. We will get better
performance if they all share the
socket.
– If the gateway is also a modbus node
(eg a 5000) we don’t need to access
the serial wire to talk to it so we will
get better communications by making
this NOT share sockets.
Modbus TCP - Error code B
• Error code B allows a gateway to send a
message back to indicate a timeout.
– Some masters do NOT support it so it must be
explicitly enabled.
– If supported it gives much better support for timeouts
from serial devices connected via gateways.
Ethernet
Serial
Summary
• Ethernet
– Physical, MAC Addresses
• IP
– Address Classes, Subnets, Gateways, address assignment
(static,BootP,DHCP), Routing
• TCP
– Connection Based, Ports & Sockets, firewalls
• Other
– DNS, Hubs, Routers, ping, nslookup, tracert
• Modbus TCP