4/9/2023 0 Comments Whiteshark airtool![]() One of very important parameters for compressor is PSI (Pounds Per Square Inch). Why? So you can learn something more than just listen to some advises.įirst of all I want to mention some properties that have effect when choosing the air compressor. What I decided to do here is to write all about compressors. Every gun has different demands on its properties, so it is really relevant which air compressor you will choose for your airbrush gun. The air has to be at certain pressure to allow us to work. First part was about airbrush guns, where I described all the types of airbrush guns that exist out there on the market and I’ve brought a few professional advises that I believe could help you to choose the right airbrush gun.īut airbrushing can not be possible without the proper air source. Preparing myself for a problem replication saved me a lot of time on customer premises in and in my lab.So here I am again with a second part of my series that I’ve started recently. I always spend a moment to think what I want to capture, on which channels, on which channel widths etc. Using best practices for Wireshark will help in troubleshooting and analysis. This is why usage of NTP server is so important for troubleshooting. Merging both files in Wireshark will lead us to false conclusions. In the meantime a wired packet capture were started: Laptop’s clock was misconfigured and a few moments later packets were captured. The easiest way is implementation of a NTP server. In such a scenario one adapter should be dedicated for specific channel.īefore taking a packet capture, it is good idea to check if all network devices (not only wireless controllers and access points) have the same time. If you need to scan channels 1, 6 and 11 and a reason for that is mobile client’s roaming problem, it is good practice to use 3 x separate adapters. Any conclusions based on such a scan might lead to wrong decisions. In this example each channel has 1/5 of the second to capture the traffic. ![]() Capture multiple channels from one adapter = bad ideaĪs an example, Wireshark or Airtool allows an user to capture traffic from more than one channel.Ĭhannels 1, 6, 11, 60 and 64 were selected.ĥ channels were selected, therefore the capture jumps from one channel to another one. Now we see communication intended for laptop and mobile client as the proper channel has been selected.ģ. I added a VHT Information -> Bandwidth () to show 20 MHz and 40 MHz data frames. The second packet capture with the proper 60+ channel: ![]() On the other hand there are laptop’s data frames as those are transmitted with 20 MHz channel width. No 40 MHz 802.11ac data frames seen obviously. There are only management and control frames for the mobile phone with 802.11a. Clients may send data frames with 20 MHz or 40 MHz width, while management and control frames will be sent at 20 MHz channel width on primary channel.ĪP transmits with 60+ channel, packet capture taken only with primary channel 60.Ģ x mobile clients associated: laptop with MAC address 28:16:ad:2f:ec:5c transmitting only 20 MHz data frames and mobile phone with MAC address cc:44:63:1b:2d:fa transmitting only 40 MHz data frames. If 40 MHz channel is used, this doesn’t mean that only 40 MHz mobile clients will be associated to the radio. There is a reason why 40 or 80 MHz channels are used and it is a faster connection. Only management and control frames are seen with 802.11a data rates, no 802.11ac data frames.Īs a comparison, second capture in the same environment was taken at the same time with another MacBook Pro with built-in 802.11a/b/g/n/ac card with Airtool: ![]() I added PHY type as a column to see differences (wlan_radio.phy): One laptop and one mobile phone associated.įirst capture is taken with MacBook Pro with built-in 802.11a/b/g/n card only with Airtool. However, you can’t collect 802.11n/ac frames with 802.11a/b/g adapters or APs.ġst wave Aruba AP with 802.11ac operating on channel 48. When taking a packet capture, you should consider what protocols and APs are installed.Įvery new protocol is backward compatible with older technologies, which means you can collect 802.11a/b/g frames with 802.11n/ac adapters. Many companies have older 802.11n or even 802.11a/g APs deployed in the production environment. Nowadays there are 2nd wave 802.11ac capable APs in the market. There are many possibilities of taking packet capture to troubleshoot a wireless or wired network or application issues.īefore you take a packet capture, there are several tips, which can save you a lot of time and money.ġ.
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