embedding tcp/ip working through … is a tcp/ip stack? the internet protocol suite—like many...

Renesas Electronics America Inc.© 2012 Renesas Electronics America Inc. All rights reserved.

Embedding TCP/IPWorking Through Implementation Challenges

Micriµm

© 2012 Renesas Electronics America Inc. All rights reserved.2 Micriµm

Renesas Technology & Solution Portfolio


Introduction : ObjectivesBlock 1 : What is a TCP/IP stack?Block 2 : Embedded system requirementsBlock 3 : LAN = EthernetBlock 4 : ARP OperationBlock 5 : Hardware/Software setupBlock 6 : IPv4 AddressingBlock 7 : IPv6 AddressingBlock 8 : Troubleshooting connectionBlock 9 : Transport protocols Block 10 : Network services and application

Agenda


Objectives

Learn to use TCP/IP properly from the start.

Understand the requirements difference to perform IP connectivity versus IP performance.

Perform TCP/IP networking activities. Record network traffic and analyze results.

© 2012 Renesas Electronics America Inc. All rights reserved.5 MicriµmMicriµm

Block 1What is a TCP/IP stack?


What is a TCP/IP stack?

The Internet Protocol suite—like many protocol suites—can be viewed as a set of layers. Each layer solves a set of problems involving the transmission of data, and provides a well-defined service to the upper layer protocols based on using services from some lower layers.

Upper layers are logically closer to the user and deal with more abstract data, relying on lower layer protocols to translate data into forms that can eventually be physically transmitted.

It has also been referred to as the TCP/IP protocol suite, which is named after two of the most important protocols in it: the Transmission Control Protocol (TCP) and the Internet Protocol (IP), which were also the first two IP networking protocols defined.


1. Device Drivers

Physical (hardware)

2. Network Access

3. Internet

5-6-7. Application

4. Transport

Telnet, FTP, TFTP, HTTP, BOOTP, DHCP, SNMP

Socket API

TCP, UDP

IP, ARP, ICMP

PPP,SLIP, Ethernet

User data

Physical Devices

AppHeader

TCP Segment

Application dataTCPHeader

Application dataTCPHeader

IPHeader

IP Datagram

14

Application data

4202046 to 1500 bytes

Ethernet Frame

Transport Protocol Messages

Network-Specific Frames

User Data(Messages or Streams)

EthernetTrailer

TCPHeader

IPHeader

IP Datagrams

Layers in the Internet Protocol suite

EthernetHeader

User data

What is a TCP/IP stack?

The TCP/IP reference model consists of four layers plus the physical layer.


Layered communication


TCP/IP Protocol ArchitectureProtocol Family


The starting point

1. Device DriversPhysical (hardware)

2. Network Access

3. Internet

5-6-7. Application

4. Transport

Telnet, FTP, TFTP, HTTP, BOOTP, DHCP, SNMP

Socket API

TCP, UDP

IP, ARP, ICMP

PPP,SLIP, Ethernet

Physical Devices Ethernet

Applications and services

Implementing TCP/IP

Understanding TCP/IP


Block 2Requirements

Performance Connectivity onlyOr Throughput?


PerformanceCPU

Most embedded targets are slower consumers when compared to laptop and desktop computers.

Packets generated by a faster producer and received by the target will consume most or all NIC network buffers and some packets will be dropped.

Hardware features such as DMA and CPU speed can improve this situation. The latter is trivial, the faster the target can receive and process the packets, the faster the network buffers can be freed.


RequirementsFootprint

For connectivity, a TCP/IP stack or a subset of it can be implemented with very few RAM (approximately 32K).

For a few Megabits per second, a more complete TCP/IP stack is required. In this case, embedded system requirements dictate in the range of 96K of RAM for a minimal sustained throughput. Resources need to be allocated to the protocol stack so that it can perform its duties.


Memory Usage Summaryof our setup

Module ROM Bytes RAM Bytes RAM %

Estimated µC/LIB ROM / RAM Usage 5380 0 0.00%

Estimated TCP-IP ROM / RAM Usage 106779 41976 61.03%

Estimated RTOS ROM / RAM Usage 29114 9852 14.32%

Estimated Probe ROM / RAM Usage 6231 5684 8.26%

Estimated HTTPs ROM / RAM Usage 7121 8756 12.73%

Estimated µC/CPU ROM / RAM Usage 1104 58 0.08%

Estimated App + BSP Code ROM / RAM Usage 9905 1338 1.95%

Other ROM / RAM Usage (cstartup, µC/CPU, CPU, µC/LCD, ...) 7406 1120 1.63%

Total Code 173040Total RAM Data 68784

8 receive buffers8 large transmit buffers2 small transmit buffers

3 receive descriptors 8 transmit descriptors


RequirementsProtocols and services

Optional protocols:IGMPICMPTCP Congestion controlTCP keepaliveTCPIP fragmentation


Questions?


Block 3LAN = Ethernet

Why Ethernet?Because Ethernet is the ubiquitous LAN (Local Area Network)

Most of the world wide data initiates or terminates on an Ethernet port (>99%).

Embedded systems sometimes use serial links (SLIP, PPP or PPPoE)


Ethernet technology

Regardless of the speed, the following aspects are always the same : Frame format Access method

SPEED STANDARD

10 MBPS IEEE 802.3

100 MBPS IEEE 802.3u

1000 MBPS IEEE 802.3z

10,000 MBPS IEEE 802.3ae

Supports various speed :


Ethernet technology

Topology

1st Generation

Today


Ethernet 802.3 Frame Structure802.3 frame format

PRE PreambleSFD Start Frame DelimiterDA Destination addressSA Source address

LEN LengthDATA ….PAD PaddingFCS Frame check sequence


Unicast (point to point) 00-02-0C-4B-59-78 = unique station address

Traffic types


Broadcast (point to all-point)FF-FF-FF-FF-FF-FF = all stations group address

Traffic types


Multicast (point to a group) 01-80-C2-00-00-01 = spanning tree group address

Traffic types


Network buffers

A TCP-IP stack network buffer includes the Ethernet frame and metadata to manage the buffer.

Header Ethernet Frame

Network Buffer

Typically 1518 (1520 for alignment)

A TCP/IP stack places received packets in network buffers to be processed by the upper protocol layers and also places data to send in network buffers for transmission. Network buffers are data structure defined in RAM.

The data portion of the network buffer contains the application data and protocol headers.


Drivers

Ethernet controllers require ‘drivers’– The software that interfaces between the TCP/IP stack and

the Ethernet controller Could be complex depending on the Ethernet controller

(1000-3000 lines) Two most popular Ethernet controller types

– Has dedicated memory– Uses main memory

TCP/IP uses main memory for ‘network buffer’– Ethernet packets need to be transferred to these network

buffers– Either copied by the CPU or through a DMA controller


Ethernet Controller Interface

CPU

Ethernet Controller

TCP/IP

Main Memory

CPU with an internal Media Access Controller (MAC).When a packet is received by the MAC, a DMA transfer from the MAC’s internal buffer is initiated by the MAC into main memory. This method generally provides for shortened development time and excellent performance.



CPU

Ethernet Controller

TCP/IP

Main Memory

Dedicated Memory

CPU with an internal MAC but with dedicated memory.When a packet is received, the MAC initiates a DMA transfer into dedicated memory. Generally, most configurations this type allow for transmission from main memory while reserving dedicated memory for either receive or transmit operations. Both the MAC and the CPU can read and write from dedicated memory and thus the stack can process packets directly from dedicated memory. Porting to this architecture is generally not difficult and provides for excellent performance. However, performance may be limited by the size of the dedicated memory; especially in cases where transmit and receive operations share the dedicated memory space.

DMA



Ethernet Controller

Internal FIFO & Memory

DMA

CPUTCP/IP

Main Memory

Cooperative DMA solution where both the CPU and MAC take part in the DMA operation.This configuration is generally found on external devices that are either connected directly to the processor bus or connected via the ISA or PCI standard. This method requires that the CPU contain a DMA peripheral that can be configured to work within the architectural limitations of the external device. This method is more difficult to port to, but generally offers excellent performance.



Ethernet Controller

Internal FIFO & Memory

CPUTCP/IP

Main Memory

External device attached via the CPU’s external bus.Data is moved to and from main memory and the external device’s internal memory via bus read and write cycles. The amount of data transferred in a given bus operation depends on the width of the data bus. This method requires additional CPU intervention in order to copy all of the data to and from the device when necessary. This method is generally easy to port and offers average performance. Parallel I/O (Non DMA)


CPU_REG32 StatusCPU_REG32 Addr



.

.

.

DMA Descriptors

DMA Descriptor List

BufDescPtrStart

BufDescPtrCur

BufDescPtrEnd

0x00 0x50 0xC20x25 0x60 0x02

.

.

.

DataBuffers

Circular DMA Descriptor List

DescriptorPointers

Register

Software

Hardware

BufDescPtrStart

Int. Ptr (BufDescPtrStart + i) % n

Step 4. With each new received frame, software increments BufDescPtrCur by 1 and wraps around the descriptor list as necessary; hardware applies the same logic to an internal descriptor pointer.

Step 1. Software allocates receive buffers.Step 2. Software allocates a list of buffer descriptors and configures each address field to point to the start address of a receive buffer.

Step 3. Software initializes three pointers. One to track the current descriptor which is expected to contain the next received frame, and two, to remember the descriptor list boundaries. Hardware is informed of the descriptor list starting address.

Step 5. When a received frame is processed, software obtains a pointer to a new data buffer and updates the current descriptor address field. The previous buffer address is passed to the protocol stack for processing. If a buffer pointer cannot be obtained, the existing pointer remains in place and the frame is dropped.

DMADescriptors and Buffers


Zero Copy

A true zero copy architecture - negating the need for performance reducing memory buffer moves.

Zero copy networking enables the network adapter to transfer data directly to or from application memory, eliminating the need to copy data between application memory and the data buffers in the operating system.


Line Rateand Packet Processing

Bytes/packet(Bits/packet)

10 Mbpsµsec/packet(packets/sec)

100 Mbpsµsec/packet(packets/sec)

1000 Mbps

µsec/packet(packets/sec)

64(512)

51.2(19,531)

5.12(195,312)

0.512(1,953,125)

256(2,048)

204.8(4,883)

20.4(48,828)

2.04(488,281)

1024(8,192)

819.2(1,221)

81.9(12,207)

8.19(122,070)

1518(12,144)

1,214(823)

121.4(8,234)

12.14(82,345)

Can the processor produce/consume data at line rate?– Depends on many factors:

Data is moved between the controller and the main memory using DMA? The CPU needs to be capable of processing all the data

Can the CPU produce or consume the data at this rate? Amount of memory available for the TCP/IP stack


IEEE 1588Timestamping in the Application Layer

PTP

UDP

IP

MAC

PHY

PTP

UDP

IP

MAC

PHY

Master Clock Slave Clock

It is 8:40Ok, thanks.

8:40

TS

TS

TS Timestamp

It is 8:40PTP packet

Milliseconds of delay variation introduced by protocol stack processing delays

Hundreds of nanoseconds to microseconds of variation introduced by network equipment processing

Milliseconds introduced by router processing

Milliseconds of delay variation introduced by protocol stack processing delays

Jitter = Delay variation


IEEE 1588Timestamping in the Ethernet Driver

PTP

UDP

IP

MAC

PHY

PTP

UDP

IP

MAC

PHY

Master Clock Slave Clock

It is …Ok, thanks.

8:40

TS

TS

TS TimestampIt is 8:40PTP packet

Hardware timestamp removes the effect of protocol stack jitter

Hardware timestamp removes the effect of protocol stack jitter

Network jitter remains. Other techniques must be used to reduce this effect.

…8:40


IEEE 1588

PHY MII MAC

IEEE 1588PTP_TSYNC

Engine

TCP/IP stack

IEEE 1588 PTP protocol

stack

SoftwareHardwareExternal

• The IEEE 1588 PTP protocol stack is shown operating at the Application layer (IEEE 1588 calls it layer 4 mode). It can also operate at the MAC layer (layer 2).• The stack can also be implemented in software only, without the physical timestamp.


WiFiEmbedded systems typical usage

WiFi Hardware

SPI Interface

Wifi Radio and Firmware

Target

TCP/UDP

IP

IF

TCP/IP

Sockets

TCP/IP Driver SPI Driver

Ext. Interrupt Driver

Handler

TxRxHandler

WiFi Driver

Application Task

WiFiTask


WiFi

System Services

Interrupt and SPI Driver

WiFi Driver

Link Managem

ent TCP/IP Stack

User Applications


Block 4ARP Operation

ARP allows us to associate a layer 3 address (like IP) with a layer 2 address (for example Ethernet) of different lengths.


The ICMP sends the command to the IP module.

Station 172.16.10.5 sends a ping request (ICMP) to the station 172.16.10.8.

ARP Operation172.16.10.5 pinging 172.16.10.8


The IP module asks the ARP module to supply it with the MAC address (Layer 2).

The ARP module consults its table. The desired IP address is not in the table.



The ARP module sends a packet «ARP request» to the Ethernet module who will send it to everyone («broadcast»).



The Ethernet module of the station 172.16.10.8 receives the Ethernet frame and realizes that it is a «ARP request».

The request is sent to the ARP module.



The ARP module acknowledges the request and replies back with an answer («ARP reply») to the Ethernet module.

The response is sent in a Ethernet frame to the the station with the IP address172.16.10.5.



The Ethernet module passes the reply to the ARP module.

The ARP module forwards the missing information to the IP module as well as keeping the information in the ARP cache.



The IP module can now send the information to the station with the IP address of 172.16.10.8 and the Ethernet address of 12:4a:07:12:b9:c0.



ARP Header

The ARP header is found at the beginning of each ARP packet.

The header contains fields of fixed length.

Each field has a specific role to play.


ARP Header

Hardware Specifies the type of hardware address (1 specifies Ethernet)

Protocol Represents the type of protocol addressing used (IP = 0x0800)

HLen Length of the physical address in bytes, Ethernet = 6

PLen Length of the protocol address in bytes, IP = 4

Operation Four values are possible

Sender Hardware Sender physical address

Target Hardware Target hardware address (normally FF:FF:FF:FF:FF:FF)

Sender IP Sender IP address

Target IP Target IP address

The possible values for the Operation field are :

1 : ARP request 2 : ARP reply 3 : RARP request 4 : RARP reply


Block 5Setup

Renesas YRDKRX63N RS-232 terminal port J-Link on board

Directly connected Ethernet LAN Software tools


Renesas Demonstration Kit YRDKRX63N


Network set-up


Windows PC (software tools)

Renesas Eclipse Embedded Studio (e2Studio)

KPIT Cummins GNURX Tool Chain

Command prompt (ping and other utilities)

Wireshark, Network Protocol Analyzer

TeraTerm Pro, Terminal emulation

IPerf, benchmarking tool for measuring TCP and UDP performance


Software Development

RenesasEclipse Embedded Studio e2 Studio http://www.renesas.com/e2studio Registration required

+KPIT CumminsGNURX Windows Tool Chain (ELF) http://www.kpitgnutools.com Registration required


Micriµm µC/TCP-IP

uC/TCP-IP is a compact, reliable, high performance TCP/IP protocol stack. Built from the ground up with Micrium'srenowned quality, scalability and reliability,

µC/TCP-IP was designed specifically for the specific requirements of embedded systems.


Network Protocol AnalyzerWireshark

http://www.wireshark.org/


IPerf (IP performance)Benchmarking Tool for measuring TCP and UDP Performance

IPerf was developed by The National Laboratory for Applied Network Research (NLANR) as a means to measure maximum TCP and UDP bandwidth performance.

IPerf is open source software written in C++ that runs on various platforms including Linux, Unix and Windows.

The source code can be found on Sourceforge: http://iperf.sourceforge.net/


Kperf Settings

On the PC side, Micriμm uses Kperf because of its ease of use.

Download Kperf from the Micriμm site at:www.micrium.com/page/downloads/uc-tcp-ip_files.


Kperf Bandwidth Graph


µC/IPerf

Micriμm ported IPerf source code to μC/TCP-IP and created a module in C called μC/IPerf.

It uses an RS-232 interface for Terminal I/O.


µC/IPerf

Client modeiperf –c xxx.xxx.xxx.xxx

Server modeiperf -s


Questions?


Lab 1ARP & Packet Capture using Ping


Lab set-up


Renesas e2 Studio : Opening Workspace

Find the Renesas e2 Studio shortcut and run the application

Select the e2 Studio workspace located at:C:\Workspcae\9L06I_Micrium_TCPIP


Renesas e2 Studio : Toolchain integration

This project uses the GNURX compiler.Click Cancel on this screen.


Renesas e2 Studio : Selecting ProjectuC_OS_III_TCPIP_HTTPs_IPerf

Left clickto expand


Renesas e2 Studio : Iperf+HTTPs Project

Application code for this example.

Board Support Package

RX63Nhardware initialization code

µC/CPU specific for the RX63N

µC/OS-IIIport code

µC/OS-III source code

µC/TCP-IP library headers

µC/IPerfsource code

CPU, LIB, TCP-IP & HTTP Server binary libraries


Renesas e2 Studio : Configuring Application

Open app.c toedit the static IP configuration

Update the IP address, Subnet Mask and Default Gatewayaccording to yournetwork setup

Locate the functionApp_TCP_Init()


Renesas e2 Studio : Building project

Build Project

Right click over the name of the project


Renesas e2 Studio : Downloading code to target

ClickDownload and Debug

SelectBinaryfile


Renesas e2 Studio : Running code

Start running to main()i.e. initialize


Renesas e2 Studio : Running code

Start running from main()


Code running

Code is running when LED7 to LED12 are blinking sequentially


Configuring the PCStatic IP settings

Right Click


PC static IP settings

Then click OK to close all the screens


Wireshark

Find the Wireshark shortcut and run the application

1- Select the wired Ethernet interface to use

2- For the first capture, click on “Capture Options”


WiresharkConfiguration

Name Resolution



Name Resolution:

Display complete address and port numbers (not aliases)


WiresharkCapture

78

Packet List

Packet Details

Packet Bytes

Display filtersCapture filters



We can also define Capture Filters



Or Display Filters


WiresharkProtocol selection

Selected protocols for the exercises:

ARP – IP – ICMP – TCP – UDP


Traffic

Let’s generate a few packets of traffic using the PING DOS command to validate our lab set-up and tools installation


Open a Command Prompt window

Find the Command Prompt shortcut and run the application

If the shortcut is not on your desktop, the next slides show you how to launch it


Command Prompt using the search box

Click Start buttonEnter “cmd” and Enter or Click OK

Click Run


Command Prompt using the Start menu

1. Select the accessories folder

2. Select Command Prompt


Using PING to create network traffic


Wireshark Packet Capture


WiresharkStop capture


PC ARP cache

List

Delete


Stopping execution

Stop Debugging


Analyzing the packet capture

ARP Ethernet

PING IP ICMP

– Type– Sequence number– Payload


Block 6IPv4 Addressing

IP address Subnets Public versus private


IP Characteristics

IP does not offer :

Connections or logical circuits Datagram acknowledgements Flow control Data error checking Retransmission of lost datagrams


IP Characteristics

Transports information in the form of packets.Fragments and reassembles packets that are too big.Finds the destination of the packets.… to create one whole entity, therefore one unique homogenous

network.

Servers

Client stations

IP


IP version 4 Header Description


Viewing the IP Configuration

Windows ipconfigLinux ifconfig


IP Address Definition

141.138.88.161

141.138.163.5

141.138.40.11141.138.2.1

141.138.70.11

Byte #


Ethernet

Unicast (point to point)

IP address types


Ethernet

Multicast (point to multipoint)

IP address types

99


Ethernet

Broadcast (point to all points)

IP address types

100


IP Address Classes

Net ID (#bytes)

Host ID (#bytes)

Class A 1 3

Class B 2 2

Class C 3 1


•• 0.0.0.0 -The network the station is connected to- Also the default route

•• The network numbers–– N.0.0.0 The network N of the class A network –– N.N.0.0 The network N.N of the class B network–– N.N.N.0 The network N.N.N of the class C network••

The broadcast addresses –– N.255.255.255 « broadcast » on network N–– N.N.255.255–– N.N.N.255–– 255.255.255.255••

127.x.x.x «Loopback address »

« broadcast » on network N.N« broadcast » on network N.N.N« broadcast » limited to this network

IP Reserved Addresses


IP Reserved Private Addresses

Private addresses for internal usage:

Class A : 10.0.0.0 Class B : 172.16.0.0 to 172.31.0.0 Class C : 192.168.0.0 to 192.168.255.0


Network Mask configuration

Number of Net ID bits

Number of Host ID bits

Network Mask

Class A 1 3 255.0.0.0

Class B 2 2 255.255.0.0

Class C 3 1 255.255.255.0


Network Mask usage


Subnetworking

Subnetworking consists of breaking up a block of addresses into multiple blocks of smaller size. Example :

• with a subnet mask of 255.255.255.0, • a class B network is divided up in 256 blocks,• each containing 256 addresses.


Subnetworking


IP version 4 Address Architecture

IP version 4 was designed with an addressing structure by classes– The addressing bits are subdivided between the hosts and the networks.

IP version 4 addressing is non hierarchical. It does not allow to representmany subnet addresses by only one higher level address

– A hierarchical addressing scheme works like the telephone network numbering plan(country code , area code , etc.)


IP Address Definition

Network NetworkAddress

Host Address

Default Gateway (Router

Address)

A 10.0.0.0 10.0.0.310.0.0.4

10.0.0.1

B 15.0.0.0 NA 15.0.0.115.0.0.2

C 17.0.0.0 17.0.0.317.0.0.4

17.0.0.1


Routing Information

For the configuration of an IP stack to be complete, we need the following values:

An IP address A network mask (or subnet mask) And a default gateway


IP Packets Routing

The function of the routing process is to select a route among one or several possible routes, along which the data will travel between the source and the destination, moving from hop to hop.


IP HeaderIDENTIFICATION


Viewing the routing information

Route Print


Gateway Setup


SubnetworkingDestination address resolution

Using the Gateway set-up, where will a packet go, if sent by the Host to a Server on the Internet?

Host IP address : 10. 10. 1.128Host Subnet mask : 255.255.255. 0Default Gateway address : 10. 10. 1. 1Destination address : 169.142. 6. 32

Destination address : 169.142. 6. 32Host Subnet mask : 255.255.255. 0Network : 169.142. 6. 0

Host address : 10. 10. 1.128Host Subnet mask : 255.255.255. 0Host network : 10. 10. 1. 0

Is the destination address in my network?NO

Where do I send it to? My Default Gateway!

IP packet header

Source address 10. 10. 1.128

Destination address 169.142. 6. 32

Is my Default Gateway on my network? YES

What is my Default Gateway MAC address? Let’s ARP if it is not already in the ARP cache!

1

2

5

6

3

4


Network Address Translation


Port Address Translation


Questions?


Block 7Why IP version 6?

Shortage of public IPv4 addresses Routing tables size Simplified configuration Increased security QoS and real-time services Mobility mechanisms Multimedia and multicast


IP version 6 Header Description

Simplified header format :–Fix 40 bytes header length.–Reduce packet processing cost in routers.


IPv6 address scope

Addresses are assigned to interfaces No change from IPv4 Model Interface ‘expected’ to have multiple addresses

Addresses have scope Link Local Site Local Global Global Site-local Link-local

Hierarchical Routing and improved addressing :– 128 bits addresses instead of 32 bits. (~3,4 * 1038)– 340,282,366,920,938,463,463,374,607,431,768,211,456

totally! – 1030 addresses par individual on the planet!


Auto-configurationStatefull or Stateless

Router

HostStateless Router solicitation message

Router Advertisement message

HostDHCP ServerIPv6

StatefullDHCP servers Multicast Group

Unicast

No manual configuration, the router specify the address prefix anddefault gateway, but no DNS server.

The host will contact a DHCP server or similar server. The server assigns anaddress from the pre-configured list.


IPv6 address structure

FP Format Prefix (Address types)SLA ID Site-Level Aggregation IdentifierINTERFACE ID Interface Identifier

The RFC 2374 describe two other hierarchical fields: TLA and NLA. IETF decided to remove the TLA and NLA fields because they are to subject to provider specific politics.

Interface IDGlobal Routing Prefix64 bits45 bits

FP3

SLA ID16 bits

« Network » « host »« Subnet »

128 bits/16 octets


Address prefix

Prefix = Network portion + Subnet. Identify the number of bits, starting from left, which represents the

network and subnet parts. The prefix representation is identical to the one used in IP version 4

with CIDR.

In a URL, the address is found between square brackets:– http://[1080::8: 800:200C:417A]:8080/index.html– The browsers are modified– The use of names (FQDN: Fully Qualified Domain Names)

is preferable.

12AB : 0000 : 0000 : CD30 : 0000 : 0000 : 0000 : 0000 / 64

16 bits 16 bits 16 bits16 bits 16 bits 16 bits 16 bits 16 bits Prefix length

Network host Subnet

Prefix


Hierarchical routing

Tier 1 : Top-Level Aggregator (provider)Intermediate Provider : Next-Level Aggregator (provider)Site : Site-Level Aggregator (user)


IP address types

1) Unicast (point to point)

A B C D E

3) Broadcast (point to multipoint)

A B C D E

2) Multicast (point to multipoint)

A B C D E

X


IP address types – RFC 3513

The type of an IPv6 address is identified by the high-order bits of the address, as follows:

Address type Binary prefix IPv6 notation

Unspecified 00...0 (128 bits) ::/128

Loopback 00...1 (128 bits) ::1/128

Multicast 11111111 FF00::/8

Link-local unicast 1111111010 FE80::/10

Site-local unicast 1111111011 FEC0::/10

Global unicast (everything else)Future specifications may redefine one or more sub-ranges of the global unicast space for other purposes, but unless and until that happens, implementations must treat all addresses that do not start with any of the above-listed prefixes as global unicast addresses.


Neighbor Discovery (ND) Protocol

RFC 2461 Replace IP version 4 ARP, plus new functionalities Use ICMPv6 Used to: Find the neighbors link-local address Find routers on the local network Maintain neighbor accessibility Allow routers to send network address and related info to hosts Used by the auto-configuration process All ND messages have a Hop Limit of 255 Messages have a link-local scope


Duplicate Address Detection

– The host initiate the address resolution process by sending to the Multicast group a request to return their layer 2 address.

– The Neighbor Solicitation Messages are Multicast:

target Multicast address FF02 : :1 :FF17 :FCCD And MAC address 33-33-FF-17-FC-CD

– If no neighbor answers, the address is unique.

Neighbor solicitation

Group MulticastAdrress

FF02 : :1 :FFXX :XXXX

FE80 : :0290 : 27FF : FE17 : FCCD

Target Host


MTU discovery process

EthernetMTU = 1500

FDDIMTU = 4500

FDDIMTU = 4500

FDDIMTU = 4500

MTU discovery message

ICMPDatagram too big

With IP version 6, routers don’t fragment packets. When fragmentation is required, it is performed by the source host. Nodes transmit packets as large as the local network can support. If MTU is too big for some links on the path, a ICMP message « Datagram Too Big »

is returned to the source. The source adjust the MTU and fragment the packet. The minimum MTU is 1280.


Minimum address configurationWindows 7

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . : DLinkDescription . . . . . . . . . . . : Broadcom NetLink (TM) Gigabit EthernetPhysical Address. . . . . . . . . : D4-BE-D9-9A-AA-FADHCP Enabled. . . . . . . . . . . : YesAutoconfiguration Enabled . . . . : YesIPv6 Address. . . . . . . . . . . : aaaa:bbbb:cccc:dddd:6c6e:b685:4fa:1b8(Preferred) Temporary IPv6 Address. . . . . . : aaaa:bbbb:cccc:dddd:a56c:dd91:e685:873(Preferred) Link-local IPv6 Address . . . . . : fe80::6c6e:b685:4fa:1b8%11(Preferred) IPv4 Address. . . . . . . . . . . : 192.168.5.247(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0Lease Obtained. . . . . . . . . . : May-01-12 4:24:04 PMLease Expires . . . . . . . . . . : May-03-12 4:24:04 AMDefault Gateway . . . . . . . . . : fe80::218:e7ff:fed8:6bdb%11

fe80::4858:bfb:12a1:6289%11192.168.5.1

DHCP Server . . . . . . . . . . . : 192.168.5.1DHCPv6 IAID . . . . . . . . . . . : 248823513DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-17-04-2A-C6-D4-BE-D9-9A-AA-FADNS Servers . . . . . . . . . . . : 192.168.5.1NetBIOS over Tcpip. . . . . . . . : Enabled


Minimum address configurationWindows 7

Tunnel adapter isatap.DLink:

Media State . . . . . . . . . . . : Media disconnectedConnection-specific DNS Suffix . : DLinkDescription . . . . . . . . . . . : Microsoft ISATAP AdapterPhysical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0DHCP Enabled. . . . . . . . . . . : NoAutoconfiguration Enabled . . . . : Yes

Tunnel adapter Local Area Connection* 11:

Media State . . . . . . . . . . . : Media disconnectedConnection-specific DNS Suffix . : Description . . . . . . . . . . . : Microsoft 6to4 AdapterPhysical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0DHCP Enabled. . . . . . . . . . . : NoAutoconfiguration Enabled . . . . : Yes

Tunnel adapter Teredo Tunneling Pseudo-Interface:

Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Teredo Tunneling Pseudo-InterfacePhysical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0DHCP Enabled. . . . . . . . . . . : NoAutoconfiguration Enabled . . . . : YesIPv6 Address. . . . . . . . . . . : 2001:0:4137:9e76:14e0:3748:b5c5:fc6b(Preferred) Link-local IPv6 Address . . . . . : fe80::14e0:3748:b5c5:fc6b%14(Preferred) Default Gateway . . . . . . . . . : NetBIOS over Tcpip. . . . . . . . : Disabled


What are the risks?

Capital expenditure

Human resources (retraining)

Security

Unproven technologies, protocols, implementations

Instability

Protocol limitations

Performance limitations


Migrating to IPv6

1. Upgrade your applications to be independent of IPv6 or IPv4.

a) Applications must be changed to use new Sockets Application programming interfaces (APIs) so that name resolution, socket creation, and other functions are independent of whether IPv4 or IPv6 is being used.

b) Update the DNS infrastructure to support IPv6 address and PTR records.

c) The DNS infrastructure might need to be upgraded to support the new AAAA records and PTR records in the IP6.ARPA reverse domain (optional).


Migrating to IPv6

2. Upgrade hosts to IPv6/IPv4 nodes.

3. Hosts must be upgraded to use a dual IP layer or dual IP stack. DNS resolver support must also be added to process DNS query results that contain both IPv4 and IPv6 addresses.

4. Upgrade routing infrastructure for native IPv6 routing.

5. Routers must be upgraded to support native IPv6 routing and IPv6 routing protocols.

6. Convert IPv6/IPv4 nodes to IPv6-only nodes.


Migrating to IPv6

IPv6/IPv4 nodes can be upgraded to be IPv6-only nodes.

This should be a long-term goal because it will take years for all current IPv4-only network devices to be upgraded to IPv6-only. For those IPv4-only nodes that cannot be upgraded to IPv6/IPv4 or IPv6-only, employ translation gateways as appropriate so that IPv4-only nodes can communicate with IPv6-only nodes.


Block 8 Troubleshooting

Using the ICMP tools Ping Traceroute


ICMP protocol

Since the IP protocol does not guarantee datagram delivery, this responsibility is left to higher layers.

The IP protocol does, however, provide a means of sending alerts and diagnostic messages using the ICMP protocol.

Such errors typically occur in intermediary routers and systems to which these datagrams are sent.


ICMP protocol

There are two types of ICMP messages :– error messages– request/response messages

IP packet

ICMP message


ICMP protocol

Message structure

The IP PROTOCOL field is equal to 1 if ICMP is used. The TYPE field is the first byte of the ICMP message. This field’s value

determines the contents of the rest of the data field. The CODE field depends directly on the TYPE field. The CHECKSUM field is the 16-bit one‘s complement of the one's

complement sum of the ICMP message.


ICMP protocol

15 ICMP

message types

ICMP Message type #

Function

0 Echo reply

3 Destination unreachable

4 Source quench

5 Redirect

8 Echo request

9 Router advertisement

10 Router solicitation

11 Time exceed

12 Parameter problem

13 Timestamp request

14 Timestamp reply

15 Information request

16 Information reply

17 Address mask request

18 Address mask reply


ICMP protocol

Error message structure :

An ICMP ERROR message always returns the following elements from the original datagram : the IP header (20 bytes) the IP options (0-40 bytes) the first (8) bytes of the data field (8 bytes)

The first eight bytes of the data field include port numbers in the case of upper layer TCP and UDP protocols. These ports indicate the applications to which the datagram belongs.


ICMP protocol

Error message structure

8 bytes


ICMP protocol

Example: Echo request and echo reply messages

TYPE8= Echo Request0= Echo Reply

IdentifierArbitrary number for linking a request with a reply

Sequential numberCounter set to 0 and incremented after reply received


ICMP protocol - PING

Echo Request (type 8) message


Echo Reply (type 0) message

ICMP protocol - PING


TTL (Time Exceed) (type 11) message used by “Traceroute”

ICMP protocol - TRACEROUTE


Questions?


Block 9Transport Protocols

Explain the operation of the transport layer protocols : UDP and TCP by

Looking at the transport mechanisms used by UDP and TCP. See the difference between UDP and TCP. Identify the header fields for both UDP and TCP.


Client – Server Model


UDP Characteristics

UDP is a communication protocol at Layer 4 of the OSI model.

It provides limited services when information is exchanged between two stations on the network.

UDP is used together with IP.


UDP Characteristics

UDP does not provide :

Connections or logical circuits. Acknowledgements of datagram reception. Flow control. Retransmission of lost datagrams.

It is a connectionless service.


UDP Header

UDP header fields


Ethernet driver configuration

net_dev_cfg.cconst NET_DEV_CFG_ETHER NetDev_Cfg_RX_Ether_0 = {

NET_IF_MEM_TYPE_MAIN, /* Desired receive buffer memory pool type : *//* NET_IF_MEM_TYPE_MAIN buffers allocated from main memory *//* NET_IF_MEM_TYPE_DEDICATED buffers allocated from (device's) dedicated memory */

1520u, /* Desired size of device's large receive buffers (in octets) */10u, /* Desired number of device's large receive buffers]. */16u, /* Desired alignment of device's receive buffers (in octets) */0u, /* Desired offset from base receive index, if needed (in octets) */

NET_IF_MEM_TYPE_MAIN, /* Desired transmit buffer memory pool type : *//* NET_IF_MEM_TYPE_MAIN buffers allocated from main memory *//* NET_IF_MEM_TYPE_DEDICATED buffers allocated from (device's) dedicated memory */

1612u, /* Desired size of device's large transmit buffers (in octets) */10u, /* Desired number of device's large transmit buffers */256u, /* Desired size of device's small transmit buffers (in octets) */5u, /* Desired number of device's small transmit buffers */16u, /* Desired alignment of device's transmit buffers (in octets) */0u, /* Desired offset from base transmit index, if needed (in octets) */

0x00000000u, /* Base address of dedicated memory, if available. */0u, /* Size of dedicated memory, if available (in octets). */

NET_DEV_CFG_FLAG_NONE, /* Desired option flags, if any */

3u, /* Desired number of device's receive descriptors. */10u, /* Desired number of device's transmit descriptors. */

0x000C0000u, /* Base address of device's hardware/registers. */

0u, /* Size of device's data bus (in bits), if available. */

"00:30:55:08:80:00", /* Desired device hardware address; may be NULL address or string ... *//* ... if device hardware address configured or set at run-time. */


JPerf

Find the JPerf icon on your desktop and run it


JPerf

J-Perf creates a DOS window.It should be minimized.

J-Perf settings window.This is the main window we will use


TeraTerm

Find the TeraTerm icon on your desktop and run it

You may have to determine and/or modified which COM port the USB-to-Serial adaptor is installed on, select the Serial interface and its port


TeraTerm


TeraTerm

Cycle the target board power or send empty lines (carriage return) from the PC to the target to trigger a response from the target

White background versus black background is a Setup->Window menu settingsChoose “Reverse”


UDP Test 1

Target PC

Server Client


UDPReception : 10 buffers, 3 descriptorsTransmission : 10 buffers, 10 descriptors

Target PC

> iperf –s –u –f m


Target PC



UDP Test 2

Target PC

ServerClient


Target PC> iperf –c 10.10.2.100 –u –f m



Target PC



UDP Test 3

Target PC

Server Client


Target PC


Maximum UDP receive performance


Target PC



Performance with Wireshark

Wireshark interfaces between the Network Interface Card and the Windows TCP/IP stack

Depending on your laptop, running Wireshark in parallel with IPerf may influence the laptop performance

Redo the UDP tests with Wireshark and validate the performance results obtained without and with Wireshark


UDP receive performance with Wireshark

Target PC



UDP receive performance with Wireshark

Do we get the same performance?


TCP Characteristics

TCP is a communication protocol at layer 4 of the OSI model.

It provides full services when information is being exchanged between two stations on the network.

TCP is used together with IP.


TCP Characteristics

TCP provides : Logical connections or circuits. Acknowledgment of datagrams. Flow control. Data error checking. Retransmission of lost datagrams. Data delivery in the correct order.

It is a connection-oriented protocol.


1

2

3

Client Server

TCP connection phases

Connection establishment

SYN

SYNACK

ACK



Information transfer

1

Client Server

ACK

PUSH

PUSH

ACK

2

1

2



Disconnection

1

Client Server

ACK

FIN

FIN

ACK

2

1

2


Connection status verification

Windows command: netstat


TCP Header

TCP header fields


TCP Header

The socket : IP address + port number.


TCP Header

CODE (6 bits)


TCP Header

SEQUENCE NUMBER (32 bits)


TCP Header

ACKNOWLEDGEMENT NUMBER (32 bits)

189


TCP Header

WINDOW (16 bits)


TCP Header

An example of WINDOW use :


TCP Header

Another example of WINDOW use :


Bandwidth * Delay Product (BDP)

BDP (bytes) = total_available_bandwidth (KBytes/sec) x round_trip_time (ms)

It is recommended to make Rx TCP Window Size (or BDP) a multiple of the Maximum Segment Size (MSS), typically a multiple of 1460.


Timers That Contribute to Data Transmission with TCP

Timers are spans of time that are used to manage the sending and retransmission of segments.

RTT (Round trip time)♦ The RTT is the time that passes between the sending of a TCP segment (SYN or

PSH) and the receipt of its acknowledgment (ACK).♦ The RTT is recalculated over the duration of the connection and varies according

to the congestion of the network.



RTT



RTO (Retransmission Time Out)

RTT

Time



Example of RTO usage :

µC/TC-IP uses a fix initial RTO.



Persist Timer

It is the waiting time before a transmission to a station when the transmission window is 0.

All TCP segments with the exception of acknowledgments (« ACK ») receive a segment acknowledging receipt.

ACK segments may be lost (just like any other TCP segment). If Station A does not receive an ACK with a transmission window > 0, it will transmit a single byte to Station B after the persist timer has elapsed.

This segment is called a « window probe ». The persist timer is always set at between 5 and 60 seconds.



Example of Persist timer usage :



KEEPALIVE

It is the maximum period of time between two activities on a TCP connection.

Many set-ups have the maximum period of inactivity set at two hours. The timer is restarted every time an activity occurs on the connection.

Keepalive



2MSL

2MSL is the maximum « keep alive » of a TCP segment on the network.

This « keep alive » is defined in the « TTL » field in the IP header.

2MSL


TCP3-way handshakeCapture and analyze a TCP connection


TCP Test 1

Target PC

Server Client


TCPReception : 10 buffers, 3 descriptorsTransmission : 10 large buffers, 10 descriptors

5 small buffers

Target PC> iperf –s –f m


Target PC


5 small buffers


TCP3-way handshake


TCP MSS optimization

Is 31.5 Mpbs the maximum TCP performance in client mode we can achieve?

The TCP Maximum Segment Size (MSS) is 1460 bytes

The IPerf default buffer size is 8K bytes

What will happen if we make the buffer an exact multiplier of the MSS?


TCP Test 2

Target PC

Server Client


> iperf –s –f m

Target PC


5 small buffers Buffer = 7300



5 small buffers Buffer = 7300

Target PC


TCP Test 3

Target PC

ServerClient


Target PC> iperf –c 10.10.2.100 –f m


5 small buffers


Target PC


5 small buffers


TCPWinsize > Number of net_bufsConfiguring TCP Window sizes


TCP Window size – Source code projectWindow size in relation to buffers

/* Configure TCP connections' window sizes ... *//* ... in integer number of octets (see Note #2) : */

#define NET_TCP_CFG_RX_WIN_SIZE_OCTET (10u * 1460u) /* Configure TCP connection receive window size. */#define NET_TCP_CFG_TX_WIN_SIZE_OCTET (10u * 1460u) /* Configure TCP connection transmit window size. */

net_cfg.h

The TCP window size should follow the number of buffers available.In our configuration, we have 3 Receive descriptors for 10 Receive buffers.This test sets the TCP Receive Window Size at 10 Receive buffers.


TCP Demo by the instructor

Target PC

Server Client


Target PC> iperf –s –f m

TCP Window sizeWindow size in relation to buffers


Wireshark capture

218

Retransmission occurring because the transmitter is overflowing the Receive buffers, degrading the

performance


Bandwidth-Delay Product (BDP)

BDP (bytes) = total_available_bandwidth (KBytes/sec) * round_trip_time (ms)

Example 1Bandwidth = 5 Megabits per secondRTT = 300 milliseconds (public internet)

BDP = 187500 bytes

It is a good practice to define the TCP window size in multiple of the TCP maximum segment size (MSS) which is normally 1460 bytes.

In this case, 187500 bytes is the equivalent of 129 buffers.


Bandwidth-Delay Product (BDP)

BDP (bytes) = total_available_bandwidth (KBytes/sec) * round_trip_time (ms)

Example 2Bandwidth = 5 Megabits per secondRTT = 3 milliseconds (private intranet)

BDP = 1875 bytes

In this case, 1875 bytes is the equivalent of 2 buffers(with a MSS of 1460 bytes).


TCPMultiple sockets

Bandwidth is shared between all active TCP connections

The BDP (i.e. number of buffers) are shared between connections. The performance of each connection will linearly decrease as the number of connection increases

Perform a system performance assessment


Removing options and optimizing the stack

File Parameter Valuecpu_cfg.h

CPU_CFG_INT_DIS_MEAS_EN DEF_DISABLED

CPU_CFG_LEAD_ZEROS_ASM_PRESENT DEF_ENABLED

os_cfg.h

OS_CFG_APP_HOOKS_EN DEF_DISABLED

OS_CFG_ARG_CHK_EN DEF_DISABLED

OS_CFG_CALLED_FROM_ISR_CHK_EN DEF_DISABLED

OS_CFG_DBG_EN DEF_DISABLED

OS_CFG_OBJ_TYPE_CHK_EN DEF_DISABLED

OS_CFG_SCHED_LOCK_TIME_MEAS_EN DEF_DISABLED

File Parameter Valuenet_cfg.h

NET_CFG_OPTIMIZE NET_OPTIMIZE_SPD

NET_CFG_OPTIMIZE_ASM_EN DEF_ENABLED

NET_DBG_CFG_INFO_EN DEF_DISABLED

NET_DBG_CFG_STATUS_EN DEF_DISABLED

NET_DBG_CFG_MEM_CLR_EN DEF_DISABLED

NET_DBG_CFG_TEST_EN DEF_DISABLED

NET_ERR_CFG_ARG_CHK_EXT_EN DEF_DISABLED

NET_ERR_CFG_ARG_CHK_DBG_EN DEF_DISABLED

NET_CTR_CFG_STAT_EN DEF_DISABLED

NET_CTR_CFG_ERR_EN DEF_DISABLED

NET_TCP_CFG_RX_WIN_SIZE_OCTET 3 * 1459

NET_TCP_CFG_TX_WIN_SIZE_OCTET 10 * 1460

The activities in this session used all these optimizations


HTTP Server

Start Wireshark Open the web browser of your choice Enter the following address: http://10.10.2.65

Use the potentiometer on the board to change the

value

Click to toggle LED15 Click to toggle LED4


HTTP ServerWireshark captureUsing Internet Explorer

Embedded Target IP Address:10.10.2.65

PC IP Address:10.10.2.100


Questions?


Block 10Applications and services

Distinguish the various network services and applications


Services

DHCP&

DNS


DHCP Service

Since all IP network equipment require unique addresses, the DHCP (Dynamic Host Configuration Protocol) protocol relieves a burden on network administrator management.

DHCP supports two types of addresses :StaticDynamic

DHCP replaces BOOTP (Bootstrap Protocol).


DHCP Service

DHCP usage example

150.100.10.8 150.100.10.10DHCP server

1

?.?.?.?

1 2Eth. s: A0.B2.C1.D3.F4.E5Eth. d: FF.FF.FF.FF.FF.FFadresse IP = ?DHCP request

Eth. s: A0.B2.C1.E6.D4.A7Eth. d: A0.B2.C1.D3.F4.E5adresse IP = 150.100.10.5DHCP reply


DHCP Service

Resulting configuration


DHCP Client implementation


Dynamic configuration of link-local addresses

RFC 3927 :

Microsoft refers to this as Automatic Private IP Addressing (APIPA)or

AutoNet in other environments.

IPv4 uses the special block 169.254.0.0/16while IPv6 hosts use the prefix fe80::/10


Zeroconf

Zeroconf – is a protocol that solves the following issues: Assigning a network address to a device using link-local address autoconfiguration Detect the presence of neighbour computers by their hostname using Multicast

DNS (Apple mDNS) or Link-local Multicast Name Resolution (Microsoft LLMNR) Detect services, such as printer using Apple's protocol: mDNS and DNS-SD (DNS

Service Discovery) Avahi – is a Zeroconf implementation for Linux and BSDs. Bonjour – also known as Rendezvous, is a proprietary zeroconf implementation from

Apple Inc. Zeroconf is built on three core technologies:

Assignment of numeric network addresses for networked devices () Automatic resolution and distribution of computer hostnames (multicast DNS) Automatic location of network services, such as printing devices through DNS service

discovery.


DNS Service

The « Domain Name System » is used to establish an association between a system name and its IP address.

It is a protocol with two parts to it : Client : Resolver Server : Name server


DNS Service

The structure of DNS is very similar to the file structures that we find in our existing systems.

It is possible to have up to 127 levels (but this is not recommended…).


DNS Service

DNS structureROOT

The DNS database is depicted as an inverted tree, with the root at the top.


DNS Service

Each element/node of the tree has a label that identifies it in relation to its parent.

The label may consist of up to 63 characters.

The root uses a reserved label, i.e. « nil character » or « ».

The levels are separated from each other by periods « . »

The label of each child belonging to a given parent must be unique.


DNS Service

Syntax of Domain Names

WWW.MYCOMPANY.COMDomain NameService Name


DNS Service

An embedded system normally implements a DNS resolver.

The DNS server is a network service.


DNS Service

Resolver

DNS

199.138.88.161

www.mycompany.com ?

www.mycompany,com is199.138.88.161

www.mycompany.com

Internet


DNS Service

Resolution mechanism

Name

Server

Root Server

.com Server

mycompany.com Server

User (resolver)

Request

Answer

www.mycompany.com

Referred to .com

www.mycompany.com

Referred to mycompany.com

www.mycompany.com

Return the requested address199.138.88.161

Root

.gov .com .net

.mycompany

www


Telnet Application

Telnet is a standard application now offered by most TCP/IP implementations on the market.

It is a widely used application aimed at establishing a connection between your computer and a remote system so you can run the remote system as if it were local.

Most telecommunications equipment on the market today, like routers and switches, support the Telnet protocol.


Telnet Application

A virtual session lets the client run applications on the server in terminal mode

> ls.. .. .. .cshrc> cd ..


SMTP Application

SMTP (Simple Mail Transfer Protocol) is one of the protocols used to transfer email messages from computer to computer using TCP/IP.

Messages take the form of emails with headers, destination addresses and messages.

About half of all TCP connections are used by SMTP!


SMTP Application

Envelope

Message Headers

Multipart/alternativeAlternative PartText/plain

Alternative PartText/html

Attachment

From : Alan Fraser from ok.eduDate : 11/09/21Subject: A message

Attachment

MAIL FROM: [email protected] TO : [email protected]

Hello Roger,This is a message. See you soon.Alan


SMTP Application

SMTP address syntax :

User@DomainUser

– A unique user on the Domain

Domain– The domain name of the network.


FTP Application

FTP is the standard Internet file transfer protocol.

FTP is one of the three most common « Net » protocols (tens of millions of email, www and FTP users).

It is a layer 7 protocol using the TCP transport service.


FTP Application


FTP Application

FTP (File Transfer Protocol) is used to transfer files from one machine to another.

The anonymous user is a generic user. This lets a client connect to a server without having an account with a given server. A minimum security can be implemented by using the user client’s email address as the password.

Ex.:Userid : anonymousPassword: [email protected]


HTTP Application

HTTP (Hypertext Transfer Protocol) is a protocol that is used to exchange files (text, video, graphics and other multimedia files) over the World Wide Web – WWW.

This protocol uses TCP/IP as the vehicle for sending and receiving data.

The protocol works in client/server mode. The client portion is embedded in the applications on the workstations.

It includes many other tools used on the Internet : News, FTP, Telnet, Email, etc.


HTTP Application


Questions?


Summary

A TCP/IP stack is a layered protocol stack Performances attained on Personal Computers may not be

the right expectations for an embedded system based on an MCU

Ethernet is the ubiquitous Local Area Network, with WiFibeing an extension of it

A network protocol analyzer like Wireshark is the best tool to troubleshoot problems and to communicate issues

IPerf is a great tool to stress your Ethernet/WiFi driver and TCP/IP stack

IPv4 and IPv6 will coexist for a long time UDP can be overrun. TCP can produce bad results when not

configured properly DHCP and DNS are network services. FTP, HTTP, Telnet

SMTP, POP3 are applications

embedding tcp/ip working through … is a tcp/ip stack? the internet protocol suite—like many...

Documents