Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Bookmarks inbookmarks:mine
inbookmarks:1234
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options answers only user 36720

For questions about OSI Layer 4 (transport layer).

2
votes
Probably the easiest answer: Imagine two LAN clients accessing the same external web server and coincidentally both using the same source port. If the NAT router now uses the same external source po …
answered Feb 1 '18 by Zac67
3
votes
Q1) A host should send ACKs as soon as possible = on a per-packet basis. However, as the text mentions it's not in violation against RFCs to only send one ACK at the end of the window. Q2) The sender …
answered Mar 23 '18 by Zac67
0
votes
Loss of SYN/ACK (2nd step) means no side has received an ACK = there's no way to send a segment. Loss of last ACK (3rd step) means that the listener (server) isn't fully synchronized but the initiator …
answered Sep 23 '21 by Zac67
2
votes
See RFC 793: Reset Generation As a general rule, reset (RST) must be sent whenever a segment arrives which apparently is not intended for the current connection. A reset must not be sent if it is …
answered Sep 16 '21 by Zac67
1
vote
There is no network solution for this. If the interface can't be fixed the only solution would be an application proxy. Essentially, on the outside you build the interface you require and on the insi …
answered Feb 16 '18 by Zac67
1
vote
Getting away without an explicit protocol identifier isn't possible because many TCP segments won't carry any information for identifying the protocol - downloading a file by FTP or HTTP can produce a …
answered Oct 19 '18 by Zac67
4
votes
The first thing to realize is that the TCP window size and the round-trip time (RTT) limit the throughput: no more than one window size per RTT can be transported. Essentially, with a large RTT (late …
answered Apr 25 '18 by Zac67
11
votes
User applications use random ephemeral ports for outgoing connections. TCP port 80 is only the server side's default port for WWW. A TCP socket connection consists of source IP, source port, destinat …
answered Mar 10 '18 by Zac67
1
vote
Check out RFC 793 3.1 Header Format Acknowledgment Number: 32 bits If the ACK control bit is set this field contains the value of the next sequence number the sender of the segment is expecting to r …
answered Aug 31 '19 by Zac67
2
votes
Port numbers are used as subaddresses on a host. That way, multiple services can run on a single host and numerous connections can be made at the same time using the same transport protocol, e.g. HTTP …
answered Nov 12 '17 by Zac67
5
votes
The guys who defined it called it Transmission Control Protocol only. The others seem to have it mixed up.
answered Feb 2 '20 by Zac67
3
votes
The triple handshake take three single trips between the connection partners A and B: A->B: SYN B->A: SYN+ACK [A is fully synchronized after receiving B's SYN/ACK] A->B: ACK [A can already send data …
answered Sep 22 '21 by Zac67
2
votes
The "pseudo header" is a way to include vital information from the IP header in the UDP checksum. You could also call it "virtual header". Basically, the UDP checksum is calculated on the UDP datagram …
answered Sep 12 '21 by Zac67
5
votes
The transport-layer protocol needs to make sure that data can be properly packetized. It it lacks support for that (like UDP), the application layer needs to take care of that. IP fragmentation in th …
answered Jul 26 '19 by Zac67
2
votes
The first diagram is misleading: TCP uses a triple handshake to establish a socket connection. There is no equivalent to that for UDP since UDP is connectionless and datagrams are simply sent away. Re …
answered Aug 23 '20 by Zac67

15 30 50 per page