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IP TCP and UDP all discard a packet that arrives with a checksum error and do not?
Only TCP will automatically discard a packet with a bad checksum. UDP packets have a checksum field, but it is rarely used, and then only by the application (not UDP itself)
The OSPF packet format has a checksum field but the RIP packet does not why?
RIP messages are wrapped in a UDP package, which already has a checksum.
Which three fields are used in a UDP segment header?
• checksum • destination port • source port
How does UDP verify datagram integrity?
It uses something called a checksum to verify datagram integrity
A UDP header contains what fields?
A UDPheader contains four 16-bit fields. They are the source port, destination port, length, and checksum -- in that order.
Features of udp?
provides connectionless, unreliable serviceso UDP faster than TCPadds only checksum and process-to-process addressing to IPused for DNS and NFSused when socket is opened in datagram mode
What does a client do when it has UDP datagrams to send?
When a client wishes to send a UDP datagram there is nothing that they are required to except to send it. The datagram will use a checksum to verify the integrity of the datagram and deliver it where it needs to go.
Why does IP TCP and UDP discard a packet that arrives with a checksum error without notifying the sender?
UDP protocol. ----------------------------------- Well my version of answer is: In the case of IP and UDP, these are unreliable protocols that do not guarantee delivery, so they do not notify the source. TCP does guarantee delivery. However, the technique that is used is a timeout. If the source does not receive an acknowledgment to data within a given period of time, the source retransmits.
What are the pieces of communication in UDP called?
UDP, or User Datagram Protocol is a very simple communication protocol. It is a part of the Transport Layer of the OSI model - the same as the well known TCP. UDP is very straight forward, containing very few features. There is no hand shaking, no security, no ordering of packets and very little error detection (if any at all). The structure of a UDP packet is as follows: Bits 0-15: Source Port Number (optional - leave as all zeros if unused) Bits 16-31: Destination Port Number Bits 32-47: The length of the entire UDP datagram (note that the maximum size is 2^16-1) Bits 48-63: The checksum (optional under IPv4 - leave as all zeros if unused) Bits 64-??: The actual data. About the checksum: this is the confusing part about UDP. When a checksum is computed, the UDP software creates a fake header to include in the checksum calculation - but this fake header is not actually transmitted. The structure of this fake header (officially called the "pseudo header") is: For IPv4: Bits 0-31: Source IP address (taken from the IP header) Bits 32-63: Destination IP address (taken from the IP header) Bits 64-71: Reserved - leave as all zeros Bits 72-79: Protocol (taken from the IP header) Bits 80-95: Length (taken from the UDP datagram) Bits 96-??: The UDP datagram described above. For IPv6: Bits 0-127: Source IP address Bits 128-255: Destination IP Address Bits 256-287: Length Bits 288-311: Reserved (leave as all zeros) Bits 312-319: Next header Bits 320-???: The UDP datagram described above NOTES: -this is only the structure of the UDP packet - and does not include the IP header. -Since it is possible for the checksum to end up as 0, the standard dictates that a checksum of zero be changed to 0xFFFF in order not to confuse with a checksum field which is disabled. This is true even under IPv6, where the checksum MUST be used. A checksum field value of zero is an error and the datagram should be discarded. -UDP makes no guarantees that the datagram will arrive, nor does it make any guarantees about the order that the datagram arrives in. If the user wants these features, then these will need to be implemented by the applications using UDP to communicate, or use a different communication protocol such as TCP.
IP TCP and UDP all discard a packet that arrives with a checksum error and do not attempt to notify the source Why?
they all discard it because if checksum error error it mean data is sent byother user and it forget its rout due to fault of channel if reach thereso it is not need to notify the source about this error
IP TCP and UDP all discard a packet that arrives with a checksum error and do not attempt to notify the source?
they all discard it because if checksum error error it mean data is sent by other user and it forget its rout due to fault of channel if reach there so it is not need to notify the source about this error (Waqas Qadeer)
Is it possible for application to enjoy reliable data transfer even when the application runs over UDP?
It is possible for an application to enjoy reliable data transfer over UDP. UDP uses checksum to learn whether data reached is true or not. You can also ensure reliability by creating a private protocol built on UDP.
