1. Page 12/9/2016 Chapter 10 Intermediate TCP : TCP and UDP segments, Transport Layer Ports CCNA2 Chapter 10

2. Page 22/9/2016 Chapter 10 The function of the TCP/IP protocol stack is to transfer information from one network device to another It closely maps the OSI reference model in the lower layers and supports all standard physical and data link protocols TCP/IP Protocol Suite

3. Page 32/9/2016 Chapter 10 provides transport services from source to destination logical connection between network end points UDP just transports data from source to destination TCP provides sliding windows, reliability via sequence numbers and acknowledgements. Transport Layer Protocols

4. Page 42/9/2016 Chapter 10 The application layer of the TCP/IP combines the functionality found in the OSI : application presentation session layers TCP/IP and Application Layer

5. Page 52/9/2016 Chapter 10 The protocols of TCP/IP that support file transfer, e-mail and remote login, include the following: Domain Name System (DNS) – translate domain name to IP address HOSTS – supports static mappings between IP & computer names Post Office Protocol (POP3) Simple Mail Transfer Protocol (SMTP) Simple Network Management Protocol (SNMP) – monitor & control File Transfer Protocol (FTP) Trivial File Transfer Protocol (TFTP) Hypertext Transfer Protocol TCP/IP and Application Layer

6. Page 62/9/2016 Chapter 10 Troubleshooting protocols: Telnet Packet Internet Groper (ping) – uses ICMP traceroute Windows based utilities: NBSTAT – trouble shoot NetBIOS NETSTAT – provides TCP/IP statistics ipconfig/winipcfg TCP/IP and Application Layer

7. Page 72/9/2016 Chapter 10 Transport layer (layer 4) enables a user’s device to segment data from several upper-layer applications for placement on the same Layer 4 data stream & enables a receiving device to reassemble the upper-layer application segments. This is a logical connection, sometimes called an end-to-end service. The transport layer provides two (2) protocols: TCP Which is connection-oriented, reliable providing flow control by sliding window and sequence numbers UDP Which is connectionless and unreliable. It’s advantage is speed. Depends on upper layers for reliability. TCP Protocol

8. Page 82/9/2016 Chapter 10 TCP (Transmission Control Protocol): layer 4 reliable connection-oriented uses windowing synchronization sequence numbers acknowledgements flow control TCP Protocol

9. Page 92/9/2016 Chapter 10 Connectionless Layer 4 protocol Non-guaranteed UDP segments do not contain sequence or acknowledgement fields Checksum is used to determine if the data or header has been transferred without corruption UDP Protocol

10. Page 102/9/2016 Chapter 10 A three-way handshake/open connection sequence synchronizes a connection at both ends before the transferred data reaches the ends. The exchange of introductory sequence numbers, during the connection sequence, ensures that any data that is lost, due to problems that may occur later, can be recovered. Three-Way Handshake

11. Page 112/9/2016 Chapter 10 Denial-of-service (Dos) attacks are designed to deny services to legitimate hosts attempting to establish connections. One type of DoS is known as SYN flooding which occurs during the three- way handshake synchronization process utilized by TCP. The hacker initiates a synchronization but falsifies the source IP address. This causes the attacked device to store the source IP address and wait for a response. This uses up system resources such as memory and processing time. One way to defend against this type of DoS is to decrease the connection timeout period and increase the connection queue size. Denial-of-Service - DoS

12. Page 122/9/2016 Chapter 10 Designed to deny services to legitimate hosts attempting to establish connections. Commonly used by hackers - hacker initiates a synchronization but spoofs the source IP address (non-existent IP address) Denial-of-Service - DoS

13. Page 132/9/2016 Chapter 10 Window size determines the amount of data that can be transmitted at one time before receiving an acknowledgement. After a host transmits the window-sized number of bytes, it must receive an acknowledgement before it can send any more messages. For example, with a window size of 1, each individual segment must be acknowledged before the next segment can be transmitted. This results in inefficient use of bandwidth by the hosts. Simple Acknowledgement Sliding Window Simple Acknowledgment

14. Page 142/9/2016 Chapter 10 TCP provides sequencing of segments with a forward reference acknowledgment. Each datagram is numbered before transmission. At the receiving station, TCP reassembles the segment into a complete message. If a sequence number is missing in the series, that segment is re- transmitted. Segments that are not acknowledged within a given time period result in re-transmission. Positive Acknowledgment and Retransmission (PAR) ensure that a number of data segments sent by one host are received by another host before additional data segments are sent. Sequence and Acknowledgment Numbers

15. Page 152/9/2016 Chapter 10 Both TCP & UDP uses IP as their underlying layer 3 protocol. TCP provides services to: FTP HTTP SMTP DNS UDP provides services to: DNS TFTP SNMP DHCP TCP/UDP Protocol

16. Page 162/9/2016 Chapter 10 Both TCP and UDP use port (or socket) numbers to pass information to the upper layers. Port numbers are used to keep track of different conversations that cross the network at the same time. Conversations, that do not involve applications with well-known port numbers, are assigned port numbers that have been randomly selected from within a specific range. 80 is web traffic Port Numbers

17. Page 172/9/2016 Chapter 10 Ports numbers have the following assigned ranges: numbers below 255 are for public applications numbers from 255 to 1023 are assigned to companies for marketable applications number above 1023 are unregulated Port numbers are located at the transport layer and are serviced by the network layer. The network layer assigns the logical address or IP. It is then serviced by the data link layer which assigns the physical or MAC address. Ports in the header of TCP & UDP are called well-known, dynamic or registered. The order of encapsulation is port number, IP address, MAC. The IANA organization is responsible in assigning port numbers for applications between 0 to 1023. Port Numbers

18. Page 182/9/2016 Chapter 10 The source hosts assigns ports numbers dynamically during the data encapsulation process. Data Segment Packet Frame TCP/UDP TCP & UDP use sockets or port numbers when creating a segment. Port Numbers

19. Page 192/9/2016 Chapter 10 ARP operates at the Internet layer of the TCP/IP layer. Given an IP address, it will find the corresponding MAC address. RARP – given MAC address, it will find the corresponding IP address. ARP