Networking

TCP and IP

Excellent write up on basics of TCP

Diagnose TCP connection setup issues

Other resources

MTU Troubleshooting Cisco IOS

Difference between IP fragments and TCP segmentation

Session Initiated Protocol (SIP)

My SIP notes

SIP parameters on nicely formatted and ad free site.

SIP tutorial

SHAKEN

Understanding STIR and SHAKEN

3GPP Long Term Evolution (LTE)

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

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

Editcap

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

Throughput

Rickard Nobel article on actual gigabit ethetnet throughput

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