vibroverbus
Regular Contributor
Another "I found this interesting so putting it in the public domain" thread for old RT-AC routers...
There is no application for this information. Its just "huh, interesting" (get ready cranky-grandpas - this might be too long and boring to read!
)
The RT-AC3200 I just deployed as a Media Bridge is working super mint, its clear the firmware is all stripped down in MB mode, this is notable in the speedy responsiveness it has when as a full on gateway router this thing is a bit of a dog.
But I see some interesting traffic coming off of it and that led me to a little curiosity digging.
ASUS gives these things 3 MAC addresses, one for each of the radios. What is interesting is what happens with them in MB mode, and, how they get assigned to the switch ports.
When in MB mode on 5G band, interestingly the network sees traffic from not 1 but 2 of the MAC addresses.
The first one requests and receives a DHCP address, but the 2nd one does not.
I have not gotten all wireshark-y on this situation, but the safe assumption would be the 2nd MAC is sending L2 traffic of some sort, ARP or whatever. Not of any significant volume but its tickling a packet out from time to time. Again I could get wiresharked I suppose but its probably not that interesting.
This led me to a little more digging in the RT-AC3200 SSH as to how those MAC addresses are used and interestingly they get assigned across the switch ports in what looks to be an odd/arbitrary way...
The "primary" MAC being bound to the bridge makes sense, but then beyond that Just kind of interesting how those MACs are assigned semi-arbitrarily across the switch ports, and, the fact that for some reason the router is sending L2 (ARP or whatever) packets on the Wifi that originate from the 2nd MAC.
There is no application for this information. Its just "huh, interesting" (get ready cranky-grandpas - this might be too long and boring to read!
)The RT-AC3200 I just deployed as a Media Bridge is working super mint, its clear the firmware is all stripped down in MB mode, this is notable in the speedy responsiveness it has when as a full on gateway router this thing is a bit of a dog.
But I see some interesting traffic coming off of it and that led me to a little curiosity digging.
ASUS gives these things 3 MAC addresses, one for each of the radios. What is interesting is what happens with them in MB mode, and, how they get assigned to the switch ports.
When in MB mode on 5G band, interestingly the network sees traffic from not 1 but 2 of the MAC addresses.
The first one requests and receives a DHCP address, but the 2nd one does not.
I have not gotten all wireshark-y on this situation, but the safe assumption would be the 2nd MAC is sending L2 traffic of some sort, ARP or whatever. Not of any significant volume but its tickling a packet out from time to time. Again I could get wiresharked I suppose but its probably not that interesting.
This led me to a little more digging in the RT-AC3200 SSH as to how those MAC addresses are used and interestingly they get assigned across the switch ports in what looks to be an odd/arbitrary way...
- MAC1: br0, eth0, eth2, vlan1, wlan1.1
- MAC2: eth1 (and presumably would be wlan2 but not visible in MB config as the radio is off)
- MAC3: eth3 (as above - wlan3 presumably if it was turned on)
The "primary" MAC being bound to the bridge makes sense, but then beyond that Just kind of interesting how those MACs are assigned semi-arbitrarily across the switch ports, and, the fact that for some reason the router is sending L2 (ARP or whatever) packets on the Wifi that originate from the 2nd MAC.
