Wireless – How does an Access Point handle broadcast packets from the wired side

wireless

I have an Cisco AP 1242AG autonomous AP connected to L2 switches.

Let's say I have 100 wired devices each sending 2 broadcast UDP packets per second.

Obviously these packets will reach the Access Point switch port, but will the AP actually send these packets (200 pps) into the air?

Thanks

Best Answer

(non-cisco specific answer)

Yes, unless you disable it.

The broadcast frames will be sent at the multicast base rate, which is typically low (1 Mbps most of the time), and only every DTIM * beacom interval if there are powersaving stations. And the packet loss rate for those will be quite high.

However, if there are no clients associated to the AP, then the AP will typically be smart and not send them.

200 broadcast packets per second, assuming a 8192 bit packet size and a 1 mbps multicast rate, will just Not Work, since the multicast traffic will be more than 1 mbps, and the AP will typically allocate much less capacity and buffers for broadcast, so the limit is actually much less than 1 mbps.


Anyway, broadcast is so 1990, if you can use multicast instead, and enable MLD/IGMP snooping on the AP, then the AP may be smarter and only deliver the multicast frames if clients actually subscribe to the multicast address. And depending on the client capabilities and the AP configuration, the multicast frames may even be sent as unicast, at higher data rates and with less packet loss.

IPv6 has no broadcast anyway.

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