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#11
Certifications and Careers / Re: Current Certification Goal...
Last post by config t - September 24, 2025, 11:54:05 AMI still want to pick up the ZT cert through CSA
#12
Certifications and Careers / Re: Current Certification Goal...
Last post by Otanx - September 23, 2025, 05:16:54 PMCongrats. Was it one of the ISC2 certs? Those are pretty well recognized.
-Otanx
-Otanx
#13
Certifications and Careers / Re: Current Certification Goal...
Last post by deanwebb - September 23, 2025, 04:43:46 PMI picked up my first cloud security certification. Feels good. 
#14
Certifications and Careers / Current Certification Goals
Last post by deanwebb - September 18, 2025, 10:01:45 AMWell, I signed on at ISC2 and I'm going to work on clearing the intro cert for cybersecurity and then going on to the cloud and AI certifications, whatever they got there. This is self-directed training on my own dime and time.
Internally, I'm going to work more on product training in Cloud / AI areas and getting up to speed in those venues. Traditional network stuff I got down very well, and finding out that AI security is basically an IPS/WAF for the AI inputs and outputs helps to put that security in context.
Internally, I'm going to work more on product training in Cloud / AI areas and getting up to speed in those venues. Traditional network stuff I got down very well, and finding out that AI security is basically an IPS/WAF for the AI inputs and outputs helps to put that security in context.
#15
Forum Lobby / Re: old Cisco hardware value
Last post by icecream-guy - August 18, 2025, 06:26:09 AMI got 30 bucks (US) a the recycle center for a bunch of old gear and a box of cables.
#16
Forum Lobby / Re: old Cisco hardware value
Last post by deanwebb - August 05, 2025, 11:21:04 AMI recycled my old gear. Getting 50 bucks and postage wasn't worth lugging it around and trying to ram it into a box.
#17
Forum Lobby / old Cisco hardware value
Last post by icecream-guy - August 03, 2025, 06:36:30 AMdoes old cisco hardware have any value anymore, 2900 & 3550 switches, 3600 routers? or is it time for the electronics recycle? I see maybe 50-60 bucks on ebay. but there are a ton.
#18
Homework Help / Re: Computing CRC (used to fee...
Last post by deanwebb - July 22, 2025, 08:32:06 AMWell, time for me to do a deeper dive into CRCs...
In networking, the CRC is typically calculated on the fly as the data goes out of the network interface and is added to the end of the transmission. There is a SHA checksum with the data that is actually used to check for data integrity, so the CRC in networking is for the datalink to determine if there are any bit errors. CRC itself is too lightweight to do a proper integrity check, which is why the SHA checksum is included with the data set proper.
In environments with low to non existent error rates, CRC can be seen as redundant, especially with TCP data being sent with a SHA checksum on it. In operational technology (OT) environments, however, where the gear is thinly provisioned and data transmission is a priority, the CRC is used on the OT protocols as a quick and easy way to determine if the data arrived completely or if a retransmission is required.
For your case, the maths are by the sending system. Honestly, it does not matter what algorithm is used, so long as it's the one for the protocol being transmitted. Humans do not calculate CRC.
The data, 1010, will be manipulated until the system gets 0 and a remainder. The remainder are the CRC bits.
https://en.wikipedia.org/wiki/Cyclic_redundancy_check#Computation shows a sample calculation.
But in the real world, we don't look at the CRCs. We *will* look at CRC error rates on a device and, when they get too high, will consider corrective action on the hardware or connecting media.
In networking, the CRC is typically calculated on the fly as the data goes out of the network interface and is added to the end of the transmission. There is a SHA checksum with the data that is actually used to check for data integrity, so the CRC in networking is for the datalink to determine if there are any bit errors. CRC itself is too lightweight to do a proper integrity check, which is why the SHA checksum is included with the data set proper.
In environments with low to non existent error rates, CRC can be seen as redundant, especially with TCP data being sent with a SHA checksum on it. In operational technology (OT) environments, however, where the gear is thinly provisioned and data transmission is a priority, the CRC is used on the OT protocols as a quick and easy way to determine if the data arrived completely or if a retransmission is required.
For your case, the maths are by the sending system. Honestly, it does not matter what algorithm is used, so long as it's the one for the protocol being transmitted. Humans do not calculate CRC.
The data, 1010, will be manipulated until the system gets 0 and a remainder. The remainder are the CRC bits.
https://en.wikipedia.org/wiki/Cyclic_redundancy_check#Computation shows a sample calculation.
But in the real world, we don't look at the CRCs. We *will* look at CRC error rates on a device and, when they get too high, will consider corrective action on the hardware or connecting media.
#19
Homework Help / Re: Computing CRC (used to fee...
Last post by networkloser - July 22, 2025, 06:55:43 AMThere are things like C(7,4), CRC-8, different representations.
#20
Homework Help / Computing CRC (used to feel si...
Last post by networkloser - July 22, 2025, 06:55:17 AMNow, I'm absolutely unsure why is CRC giving me a headache. 
Say I've this data to be sent with CRC:
1010
Now, I need CRC bits for this. Fourouzan and Kurose Ross book are too dense for me currently. Can anyone share some insightful materials to learn this? Something easier for my brain.
Grateful to any kind of help. Chatgpt and deepseek seems to be in what direction they have no idea
Say I've this data to be sent with CRC:
1010
Now, I need CRC bits for this. Fourouzan and Kurose Ross book are too dense for me currently. Can anyone share some insightful materials to learn this? Something easier for my brain.
Grateful to any kind of help. Chatgpt and deepseek seems to be in what direction they have no idea