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TCP and IP

Excellent write up on basics of TCP

Diagnose TCP connection setup issues


Excellent write up on some TCP/IP information by Stephen Cleary

Detection of half opened dropped connections

Other resources

MTU Troubleshooting Cisco IOS

Difference between IP fragments and TCP segmentation

TCP/IP Performance Tuning

Enabling High Performance Data Transfers notes for users and system administrators who want to maximize TCP/IP performance on their computer systems.

bandwidth-delay product, aka "Long Fat Network" (LFN), is the product of a data link's capacity (in bits per second) and its round-trip delay time (in seconds)

TCP window scale option is an option to increase the receive window size allowed in Transmission Control Protocol above its former maximum value of 65,535 bytes. This TCP option, along with several others, is defined in IETF RFC 1323 which deals with long fat networks (LFNs).


Study on the Performance of TCP over 10Gbps High Speed Networks

10 Gbps TCP/IP streams from the FPGA for High Energy Physics

Session Initiated Protocol (SIP)

My SIP notes

SIP parameters on nicely formatted and ad free site.

SIP tutorial


Understanding STIR and SHAKEN

3GPP Long Term Evolution (LTE)

System Architecture Evolution (SAE) and the Evolved Packet Core (EPC) tutorials

LTE interfaces

CSCF in VoLTE the P-CSCF part 1 of 4

Wireshark and related stuff

Wireshark docs

Wireshark Manual (man) pages

editcap man page

Capture Filters

Capture filter examples

Filter by destination IP address dst host x.x.x.x

Filter by a set of TCP ports tcp port 22 or tcp port 443 or tcp port 8080

Filter by TCP/UPD port port 5060

Display filter examples

Filter out TCP Keep-Alive and TCP Keep-Alive ACK with this filter:

!(tcp.flags.ack && tcp.len <=1)

Filter by port 442 and remove TCP Keep-Alive and TCP Keep-Alive ACK with this filter:

tcp.port == 443 && !(tcp.flags.ack && tcp.len <= 1)

Add custom columns

Add TCP length column to Wireshark

TCP length column


Export from network capture all TCP payloads using a display filter as octet stream (ASCII hex stream)

tshark -r <file_name> -Y "ip.src== && tcp.port==22222" -T fields -e data > output_file_name.txt


Reference editcap man page

Saves only packets whose timestamp is on or after start time. The time is given in the following format YYYY-MM-DD HH:MM:SS.

Example of timestamps after 2018-12-26 00:00:00 using PowerShell:

& 'C:\Program Files\Wireshark\editcap.exe' -A "2018-12-26 00:00:00" infile outfile

Example to limit capture file from frame number 890000 to 910000 (inclusive) using PowerShell:

& 'C:\Program Files\Wireshark\editcap.exe' -r infile.pcap smallerOutFile.pcap 890000-910000

Note: smallerOutFile.pcap in above example will have different frame numbers (counting starts over when you open file).

Gigabit Ethernet


Rickard Nobel article on actual gigabit ethetnet throughput


My Cisco ASA Notes


T1/E1 info

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