- From: Ted Guild <ted@w3.org>
- Date: Tue, 01 Sep 2020 15:19:25 -0400
- To: Gunnar Andersson <gandersson@genivi.org>, Ulf Bjorkengren <ulfbjorkengren@geotab.com>, public-automotive <public-automotive@w3.org>
- Message-ID: <7981bddde55b5b0c45039b0c385feee05252159b.camel@w3.org>
As mentioned, asking around and was encouraged by a colleague to look at JSON compression schemes. https://www.lucidchart.com/techblog/2019/12/06/json-compression-alternative-binary-formats-and-compression-methods/ On Tue, 2020-09-01 at 15:10 -0400, Ted Guild wrote: > On Tue, 2020-09-01 at 11:28 -0400, Ted Guild wrote: > > We can/should also explore alternate formats Gunnar suggested > > > > https://en.wikipedia.org/wiki/Apache_Avro > > https://en.wikipedia.org/wiki/Protocol_Buffers > > > > As these messages being transmitted are fairly small to begin with > > and > > in-vehicle use case will have extremely low latency, I also want to > > try > > to understand how/where this would be more useful as > > encoding/compressing and decoding will cost time and depending on > > method non-negligible cpu. If the client app is just sampling to > > offboard and won't unpack (decode), then we probably should look at > > Extended Vehicle and other solutions being used for off-boarding in > > addition to formats. What problem[s] are we trying to solve here? > > We confirmed on the call today the primary use case is for off > boarding > data. > > For a variety of reasons (security, connectivity, car being off), > data > being off-boarded from vehicle to the cloud will be pushed, not > pulled. > > Gen2 server instance can reside either in-vehicle or on a server in > the > cloud. > > For in-vehicle client apps that will be residing on the vehicle or > nearby (local network) trusted devices, compression is not needed. > Cloud servers will not be permitted to connect to Gen2 (ports not > open) > on a vehicle to make pull requests. Gen2 supports clients making > pulls, > HTTP GET and subscribe on Web Socket, it cannot initiate a push to > server in the cloud. > > Gen2 supporting alternate, including binary, formats besides JSON for > more efficient local storage until it can send buffered data off the > vehicle would help with 'every byte counts' when sending data off the > vehicle. > > VSS in protobuf format can make a ton of sense, perhaps with some > further optimization along lines of what Ulf and Sanjeev have been > working on. > > Gen2 server residing in the cloud, exposing data already off-boarded > can respond to pull requests from client apps running elsewhere in > the > cloud. Compression makes sense there. > > If someone has a different architecture in mind where vehicle<->cloud > connections differ fundamentally or we can translate a pull to push > by > redirecting and caching/buffering data, I would like to hear it. > -- Ted Guild <ted@w3.org> W3C Automotive Lead https://www.w3.org/auto
Received on Tuesday, 1 September 2020 19:19:29 UTC