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ECE Department: University of Massachusetts, Amherst ECE 354 Lab 3: Transmitting and Receiving Ethernet Packets.

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Presentation on theme: "ECE Department: University of Massachusetts, Amherst ECE 354 Lab 3: Transmitting and Receiving Ethernet Packets."— Presentation transcript:

1 ECE Department: University of Massachusetts, Amherst ECE 354 Lab 3: Transmitting and Receiving Ethernet Packets

2 2 ECE 354 Big Picture Introduction  Transmit and Receive Ethernet packets between two DE2 boards  Implement the 5-layer Internet model  Primarily written in C code  Use a preexisting SOPC system from the DE2_NET project

3 3 ECE 354 Skills to learn  Understanding previously written code  Using a peripheral device: DM9000A chip  Connect to a device that you did not design: DM9000A Ethernet chip  Internet protocol stack

4 4 ECE 354 Additional Hardware  Two DE2 boards  Ethernet cable

5 5 ECE 354 The Internet protocol stack –as we will use it  Consists of 5 layers: Application, Transport, Network, Link, and Physical layer; ignore Session and Presentation (OSI)

6 6 ECE 354 Overview of Lab  Each group should specify the information in Layers 2 through 5 (Link, Network, Transport, and Application)  The payload should be 16 bits selected by 16 switches (switch_pio) on the DE2 board and should be displayed on the LEDs (led_red) of the other DE2 board  Only packets with the correct source MAC, IP, and port addresses should be allowed to update the LEDs  Each group should modify the DM9000A.H file so that the last byte of the MAC address matches their group number  Test protocol compliance by working with another group and using their MAC address as your destination MAC address and your own MAC as the source. This shall fail (or else you need to update it).

7 7 ECE 354 Overview of DE2_NET project  Important files: hello_led.c, DM9000A.c, and DM9000A.h  Three functions to control DM9000A chip DM9000_init(); TransmitPacket(TXT, length); ReceivePacket(RXT, &length);  Copy the DE2_NET from the DE2 CD and use that project in Quartus.  If running two boards on the same computer, make two folders with each holding a copy of the DE2_NET project

8 8 ECE 354 Layers you will use  Create an Application Layer (5) message (data) by using the sixteen switches on the DE2 board  Encapsulate it into segment at the Transport Layer (4)  Encapsulate the segment in a datagram at the Network Layer (3)  Encapsulate the datagram in a frame at the Link Layer (2)  The frame will be sent over the Physical Layer (1)

9 9 ECE 354 User Datagram Protocol (UDP) – Layer 4 (Transport Layer)  The Application Data will be encapsulated within a UDP segment  The Segment Header includes the Source Port, Destination Port, Length of Segment, and Checksum  The Source and Destination Port numbers can be determined by the user, but the Length and Checksum will have to be calculated.

10 10 ECE 354 The Network Layer (3) - IPv4  The Segment from the Transport Layer will be encapsulated within an IPv4 Datagram  Dominant network layer protocol on the internet  Data-oriented protocol to be used on a packet switched network, such as Ethernet  Note about Checksums: Begin by first setting the checksum field of the header to zero. Checksums involve the one’s compliment addition operation. In C take the one’s compliment of a number A by: unsigned int complimentA = ~A

11 11 ECE 354 IPv4 packet structure  Packet consists of two sections:  The parts of each section that you will use in the is lab are:  Version: IP packet version (4)  Header length (between 5 and 15)  Total Length (size of datagram)  header and data  Identification: uniquely identifying fragments  Header checksum  Source and Destination address  Data

12 12 ECE 354 Link Layer (2) – Ethernet Frame  The Datagram from the Network Layer is encapsulated within an Ethernet Frame  The Destination and Source MAC addresses should be set to uniquely identify each DE2 board  Extra credit will be awarded if you perform CRC Checksum, otherwise set it to a value of zero

13 13 ECE 354 The Physical Layer (1)  Refers to the network hardware or physical cabling  Provides the means of transmitting raw bits  You can also use a loopback (included with kit) to send packets back your own board

14 14 ECE 354 What to demonstrate  Display data payload on the red binary LEDs  Display the number of packets transmitted on the seven segment display  Only packets with the correct source MAC address, IP address, and port address should be displayed

15 15 ECE 354 Where does this project lead?  The next Lab (number 4) will put Lab 2 and Lab 3 together  Implement a reliable system

16 16 ECE 354 References  The two documents located at DE2_System_v1.6\Datasheets\Ethernet  DE2_System_v1.6\DE2_demonstrations\ DE2_NET project  For detailed description of headers uite uite  Method of calculating the CRC check check

17 17 ECE 354 Comments and/or Questions

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