cancel
Showing results forĀ 
Search instead forĀ 
Did you mean:Ā 

AP's being slammed by multicast requests? LLC packets are hitting 40,000. Our ssids are on different vlans. Any guidance one how to correct this problem is greatly appreciated. Thanks!

AP's being slammed by multicast requests? LLC packets are hitting 40,000. Our ssids are on different vlans. Any guidance one how to correct this problem is greatly appreciated. Thanks!

donotusemhudgen
New Contributor
AP's being slammed by multicast requests? LLC packets are hitting 40,000. Our ssids are on different vlans. Any guidance one how to correct this problem is greatly appreciated. Thanks!
8 REPLIES 8

samantha_lynn
Esteemed Contributor III

Thanks for letting me know, but I've honestly never seen that error before. Maybe try a new packet capture? Did you alter the default port from 2002? If you send me a screen shot at communityhelp@aerohive.com, I'll try to look further in to it. Also are you using any filters in the packet capture? If you'd like assistance running the packet capture, you might want to open a case so a technician can run one with you.

donotusemhudgen
New Contributor

@Sam Pirokā€‹ , when I run wireshark I do get these 2 bits of info:

 

'new fragment overlaps old data'

 

'Transmission Control Protocol, Src Port: 56359, Dst Port: 52512, Seq: 739261400, Ack: 1, Len: 1448'

jnesci
New Contributor II

Google thought it was a good idea to allow Chromebooks to receive updates from neighboring devices. Instead of each device getting them directly from Google, only one would get them from Google and the rest would get them from neighboring Chromebooks on your network. It does this by sending Multicast requests across your network to request the update locally rather than sending the request out your Internet circuit - hence a multicast storm.

 

The Pre-fetching is how Google makes their cheap $200 devices appear as fast as a $1,500 MacBook. Each time you visit a web site, the Google browser crawls the entire site and pre-caches any links on the site so when you click on a link, it already has that information pre-loaded and appears fast. If you have a class room with 30 students looking at a site that has links to 10 videos, imagine how much data is being pre-cached, and they may never even click on those videos.

 

I did a test with this last summer and when 30 devices went to a teacher web page with several links, you could watch the CPU on the AP jump to 80 - 100%. The Chromebooks would then appear to drop off the network. I turned off the Pre-caching and the CPU on the AP stayed at 10 - 15% under the same test.

 

donotusemhudgen
New Contributor

Thanks @Joe Nesciā€‹ , and yes we are managing in GAC. I've just updated those settings and we'll see what happens.

 

So what exactly was the correlation between those settings and wireless traffic?

GTM-P2G8KFN