Re: [Bloat] [Make-wifi-fast] [bbr-dev] Aggregating without bloating - hard times for tcp and wifi

[Bob McMahon <bob.mcmahon@broadcom.com>]

[-- Attachment #1.1: Type: text/plain, Size: 3639 bytes --]

I don't know Qualcomm's offerings but here are some from Broadcom.

https://www.broadcom.com/products/wireless/wireless-lan-infrastructure/bcm67263

The BCM4916 forwarding plane is done with a network processor and doesn't
run Linux.  Linux may be used to build the forwarding tables and this is
standard "merchant silicon" forwarding approcch, let some CPU/stack build
the topology tables and then realize the packet forwarding in
(programmable) hardware.

https://docs.broadcom.com/doc/4916-PB1XX

Bob

On Tue, Nov 22, 2022 at 12:28 PM Bob McMahon <bob.mcmahon@broadcom.com>
wrote:

> Some main purposes of the WiFi CPU is 802.3 to 802.11 L2 translational
> bridging and handling 802.11 protocols for things like association. Most
> forwarded packets don't hit the main CPU anymore. This first sw to hw
> transition occurred decades ago with real internet routers (equipment that
> run IGPs and BGP) which started as software in the early 90s and then moved
> to hardware. The same engineering has been happening for home gateways or
> WiFi APs bridging wired to wireless.
>
> Bob
>
> On Tue, Nov 22, 2022 at 12:16 PM David Lang <david@lang.hm> wrote:
>
>> sorry, when I was saying 'the cpu', I was meaning the main one running
>> linux,
>> not something that's part of the wifi chipset.
>>
>> I would be very surprised if the wifi chipset is doing any packet
>> routing, as
>> opposed to just sending the packets to the main processor.
>>
>> Remember, the common case isn't forwarding from one wifi device to
>> another, it's
>> moving between wifi devices and the wired uplink.
>>
>> David Lang
>>
>> On Tue, 22 Nov 2022, Bob McMahon wrote:
>>
>> > An AP's radio complex may have a CPU but that doesn't mean it is the
>> > standard linux stack as most think of it. Many consider this as part of
>> > "firmware" which can be Linux, a Linux derivative or other.  Also, there
>> > are some levels of wired/wireless forwarding plane integration done at
>> the
>> > hardware level that many might be surprised by.
>> >
>> > Bob
>> >
>> > On Tue, Nov 22, 2022 at 12:03 PM David Lang <david@lang.hm> wrote:
>> >
>> >> On Tue, 22 Nov 2022, Bob McMahon via Make-wifi-fast wrote:
>> >>
>> >>> Finally, many (most?) APs are forwarding and feeding packets at at the
>> >>> hardware level so not sure that the linux stack matters as much for
>> an AP
>> >>> based analysis, particularly when considering multi user
>> transmissions,
>> >>> i.e. multiple WiFi clients are active and sharing TXOPs.
>> >>
>> >> APs forward packets within the switch at the hardware level, but the
>> >> radios have
>> >> to go through the CPU, so any wired <-> wireless needs to go through
>> the
>> >> CPU,
>> >> and I would be incredibly surprised if the wifi chips did wireless <->
>> >> wireless
>> >> routing at the hardware level.
>> >>
>> >> David Lang
>> >>
>> >
>> >
>>
>

-- 
This electronic communication and the information and any files transmitted 
with it, or attached to it, are confidential and are intended solely for 
the use of the individual or entity to whom it is addressed and may contain 
information that is confidential, legally privileged, protected by privacy 
laws, or otherwise restricted from disclosure to anyone else. If you are 
not the intended recipient or the person responsible for delivering the 
e-mail to the intended recipient, you are hereby notified that any use, 
copying, distributing, dissemination, forwarding, printing, or copying of 
this e-mail is strictly prohibited. If you received this e-mail in error, 
please return the e-mail to the sender, delete it from your computer, and 
destroy any printed copy of it.

[-- Attachment #1.2: Type: text/html, Size: 4800 bytes --]

[-- Attachment #2: S/MIME Cryptographic Signature --]
[-- Type: application/pkcs7-signature, Size: 4206 bytes --]