Question 1. What is the difference between a process-to-process delivery and a h

Question

Question 1. What is the difference between a process-to-process delivery and a host-to-host delivery?

Answer.

Question 2. What is a socket address?

Answer.

Question 3. Why would an application use UDP instead of TCP?

Answer.

Question 4. What is the purpose of a sequence number in a TCP packet?

Answer.

Question 5. Name the timers used in TCP?

Answer.

Question 6. In cases here reliability is not of primary importance, UDP would make a good transport protocol. Give examples of specific cases.

Answer.

Question 7. What is the minimum size of a UDP datagram? What is the maximum size of a UDP datagram?

Answer.

Question 8. What is the maximum size of a TCP header? Whatis the minimum size of a TCP header?

Answer.

Explanation / Answer

1)   Host to host communication is the one which takes place between one host and the other host(computer). IP protocol is used.

Process to Process communication refers to the communication between two processes on the
hosts. UDP protocol is used to deliver the message from the host to the process.


Thus UDP and IP protocols play a major role in the delivery of the message to the particular
process ( the difference being IP delivers the message to the destination host.UDP delivers
the message from the host to the process that is in the host).

2)   

Socket Addresses

Sockets can be named with an address so that processes can connect to them. The socket layer treats an address as an opaque object. Applications supply and receive addresses as tagged, variable-length byte strings. Addresses always reside in a memory buffer (mbuf) on entry to the socket layer. A data structure called a sockaddr can be used as a template for referring to the identifying tag of each socket address.

Each address-family implementation includes subroutines for address family-specific operations. When addresses must be manipulated (for example, to compare them for equality) a pointer to the address (asockaddr structure) is used to extract the address family tag. This tag is then used to identify the subroutine to invoke the desired operation.

Socket Address Storage

Addresses passed by an application program commonly reside in mbufs only long enough for the socket layer to pass them to the supporting protocol for transfer into a fixed-sized address structure. This occurs, for example, when a protocol records an address in a protocol control block. The sockaddr structure is the common means by which the socket layer and network-support facilities exchange addresses. The size of the generic data array was chosen to be large enough to hold most addresses directly. Communications domains that support larger addresses may ignore the array size.

3)   The User Datagram Protocol (UDP) is a transport layer protocol for use with the IP network layer protocol. It provides a best-effort datagram service to an end system (IP host). UDP provides no guarantee for delivery and no protection from duplication, but the simplicity of UDP reduces overhead from the protocol and can be adequate for some applications.

A computer may send UDP packets without first establishing a connection to a recipient. The computer completes the appropriate fields in the UDP header (PCI) and forwards the data together with the header for transmission by the IP network layer.

Typically, use UDP in applications where speed is more critical than reliability. For example, it may be better to use UDP in an application sending data from a fast acquisition where it is acceptable to lose some data points. You can also use UDP to broadcast to any machine(s) listening to the server.

In general:

4)

5)   

The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite (IP), and is so common that the entire suite is often called TCP/IP. TCP provides reliable, ordered and error-checked delivery of a stream of octets between programs running on computers connected to a local area network, intranet or the public Internet. It resides at the transport layer.

Web browsers use TCP when they connect to servers on the World Wide Web, and it is used to deliver email and transfer files from one location to another. HTTP, HTTPS,SMTP, POP3, IMAP, SSH, FTP, Telnet and a variety of other protocols are typically encapsulated in TCP.

Applications that do not require the reliability of a TCP connection may instead use the connectionless User Datagram Protocol (UDP), which emphasizes low-overhead operation and reduced latency rather than error checking and delivery validation.

Source port (16 bits)

identifies the sending port

Destination port (16 bits)

identifies the receiving port

Sequence number (32 bits)

has a dual role:

Acknowledgment number (32 bits)

if the ACK flag is set then the value of this field is the next sequence number that the receiver is expecting. This acknowledges receipt of all prior bytes (if any). The first ACKsent by each end acknowledges the other end's initial sequence number itself, but no data.

Data offset (4 bits)

specifies the size of the TCP header in 32-bit words. The minimum size header is 5 words and the maximum is 15 words thus giving the minimum size of 20 bytes and maximum of 60 bytes, allowing for up to 40 bytes of options in the header. This field gets its name from the fact that it is also the offset from the start of the TCP segment to the actual data.

Reserved (3 bits)

for future use and should be set to zero

Flags (9 bits) (aka Control bits)

contains 9 1-bit flags

Related Questions

Navigate

• Browse (All)
• Browse Q
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.