2 weeks ago
We had a problem with lots of traffic that was broadcast on our Motorola GPON system. They did not have specific guidence on what the MAC ageing time should be, but provided some general rules.
Make sure when you increase the ageing time you do not max out the total number of MAC addresses a piece of equipment can handle. We found that may be less than what is in the specs.
The ageing time of the upstream device(s) should be similar.
The default ageing time for the Moto gear was 300 seconds, we ended up going as high as 1200 seconds on most of the OLTs, but found 900 seconds to work the best on a couple. Our gateways devices are set to 1100 seconds. Most of those OLTs have around 1500 ONTs connected.
We arrived at those numbers by running Wireshark on a computer connected to an ONT and watching for packets whose destination IP is not the IP of the computer running Wireshark. We raised the ageing time until the traffic was at a level we could be comfortable with. For example going to 1800 from 1200 seconds did reduce the broadcast of traffic, but the percent reduced from 1200 seconds was minimal. The two OLTs that are at 900 second ageing time had odd behavior at 1200 seconds even though the configuration of the OLTs was otherwise the same as others that worked fine at 1200 seconds.
I could not find a MAC ageing time setting on the E7-20, any clues where it is ?
a week ago
So just an update on sorin and my situation, we did a maintenance last night turned off HSRP on a VLAN with 1200 hosts set arp aging to 270 on cisco and 300 mac agging across our cyan/ciena switching and calix, which basically dropped all the broadcast and unicast flooding close to zero. It looks like it was a mixture of things that where happening as we did it in steps and could see a big changes each time and last we turned off HSRP and it dropped to basically zero.