To: Olaoluwa Osuntokun <laolu32@gmail.com>,
 Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>,
 Antoine Riard <antoine.riard@gmail.com>
References: <CALZpt+GBPbf+Pgctm5NViNons50aQs1RPQkEo3FW5RM4fL9ztA@mail.gmail.com>
 <CAO3Pvs8rkouxQY912VW04pmn-hdAhMNL_6E_nXDmkeibBegwkA@mail.gmail.com>
From: Braydon Fuller <braydon@purse.io>
Autocrypt: addr=braydon@purse.io; keydata=
 LS0tLS1CRUdJTiBQR1AgUFVCTElDIEtFWSBCTE9DSy0tLS0tCgptUUlOQkZzRWthc0JFQUM0
 b1BKUXNGV0FNME9qTkpsWVV4SmJUVjhibzFUZ1h3WmROWldld0c2ZnZRUStpR0dJCm15L2E1
 aDEwLzlWKy9DdGlvOGF5QWZwazZWM3ovdnhxOElkUFZjc1djY0hMbmd1YUFFRWhZbktkR1pm
 c29oY1EKTU80TFI2M1I2dlByVVlVSmVoVnp0MllaNUY0OTVpUkRLd2JRTFhibVhGOXZMdGFL
 dWYvNmhiVm1sRzdiTTU5ZQpWS2N2cEU4RUttOTVMcHcrQ0JFM3VLYzNSeFRjS0hnbzZRcmtD
 bG0xOUdORERrbUh4TS9rK2hHVDNNK3NYR2hnCnBMMjk0MEFHS3NYdVRQZ2hnTFErNXNlQld0
 enVXVjMxVWYwbHRIeDZLczF3MG1sZ1paK3U0d2xsak1ISUJLTHIKNGNZRE9GOEFZeHlWY1B6
 dVFMZFJqSUlLRWdwTURRVzdmdGJnR00vcWhnR2cybU4wMzZLVFVmVDFIa21UODJaMwpEM3o0
 QUNKL2JZL0orbUp3MGJhcWNKcGV6bmRkMU02ZG5ETkY5U2xzdDJNcitMb2VKZE4xdFk1a2s2
 L09Xd0FJCjVMMTVobWRpUldVQnJ5SnF1bjdzeTIzY21WUFNPcnRhSWZsNy9TRUZKK011WGJL
 NTMrbUZHVDJQQ3BkUnpWNE0KcktyOXFiQmFYa2todkVmb0wyejZWd0lGQnBycVpqdGhQSGNI
 UjhyNlFTVHBaZHNEKzcrcW9xMm80TURVcVA1NAo1YTNrR0kzbDZWVzc2N1ZFL05VSW9jeU83
 WjlEL0VaT0NrMjJFbFRMVEN6V20wSnZ4eEdKb2FsZWJMUWNHZXkvCkE5V1dHT3YveWR3dlRy
 eTNQV0F6cnJYTnQ0M01jSEh3WlhVNHZTTG5BdEF4UXkwNk50OXdzV28rMlFBUkFRQUIKdENG
 Q2NtRjVaRzl1SUVaMWJHeGxjaUE4WW5KaGVXUnZia0J3ZFhKelpTNXBiejZKQWxRRUV3RUlB
 RDRDR3dNRgpDd2tJQndJR0ZRZ0pDZ3NDQkJZQ0F3RUNIZ0VDRjRBRkNRVlp2cGdXSVFSYmZj
 V05rUDdCNlpDakVMcnlUeU10CkVJczYxQVVDWG90VmJBQUtDUkR5VHlNdEVJczYxTVVJRC80
 blpZN0lDeUhock1iNDNaOEcrVE45TzE1WlFON2sKWlNzZ2hWeWxpcW15cE1lNWFGOWNkbFUz
 a1VkR1BEbUVuWjgweTc1bmZheXFpdlpCOG1HYXFJSTkycXVLNFJ2TQphc0kzdlQ5Rkl0Z2g4
 Nkh6NWRHa1g4eGVEZms0SkNmWml0SUQydDJVdUR1Z3JGc2VFMVE4OTJsZ21NcGZQQ3VoCk5I
 NWxDWnUzVjNnNFJDdlAxd1Jjd09XY0dXU0wwR0pvOHJrRS9tYzBKS0NGNDdwbDFFUWVRUVp5
 czIxTHBOTnYKWmFMVHJoQUpPdDFIRXBheUlxdXFKTzA4TzBMZGErelF1Z2szV0hHWUNyeXlJ
 ZFdiSWljdUFsbmowa0J1ajZKagpFdVphNFNRdE0wenF5QzNCbmIzdXBBSkNGOVdmL1lUcyts
 cUJTNW96ekxkTXJRSlo5VTE4VmxUZCtZeU9icjFBCkY0UW5xT1g2aDJlNE02KzZuOWlIdU9o
 eWlEdTI4cms2dU9sY1lOQTVXcm9mV0dFK1AyYS9zOExGOGxEZ1BtQlIKMjNmT0hrSmFtK2FB
 U1R6VVVJSC9GM0NqbkhkTzU1cHJDWDRPOUJWc2FOR2J6WHRhMzFYVnZQbE1qQXpPc3ZWegpT
 SitzUjRvMjkyVjE3THdkZU11OUFNK3c1YSt3Yk5kVnA2OEtmRnh2OTliaSs0QWgvNlVrQ2Js
 dHdQWkJqVS9nClp1WGhXM2s0Z3J6a3pwdmd1U3JEU1NHNzdDNC9QTjB4aFFRMTVlaEdlQkNl
 YWd2Ui9EZWxRQnkwMUYvTC9NV3EKSkJZTTVwN3ptR1htSlJXTWRNMDlDMThBc1NVZnMySWxl
 dnN4a3RJWFQzSUFsVU9wdG14RlJTRWlLSERwNlJ2NgpweWM2TWJSWWZGN1BGYlFrUW5KaGVX
 UnZiaUJHZFd4c1pYSWdQR052ZFhKcFpYSkFZbkpoZVdSdmJpNWpiMjArCmlRSllCQk1CQWdC
 Q0Foc0RCZ3NKQ0FjREFnWVZDQUlKQ2dzRUZnSURBUUllQVFJWGdBVUpCVm0rbUJZaEJGdDkK
 eFkyUS9zSHBrS01RdXZKUEl5MFFpenJVQlFKZWkxVnlBaGtCQUFvSkVQSlBJeTBRaXpyVTVJ
 Y1AvMXVmOUlrQgpsd2h3TG5CUjQ2QkM5NTgyOVN3MnBzTTZYTDZ6OXIrVUtmUTFSdm9pTDQ5
 V2FzU1Z6QUJGVjlnNVhRbllUajVVCkgrTnFTK29lTXlScTl0d1Avb3JFN2crVDRTNzRpaGFx
 YzFhZTZmY3pNaDRIc3NkbmtyZ2FLbTVoRXEzQjh1V08KNzRSaHRJUnczUVpzM2lqSHoxU2w3
 K1NzNklEOC9IbHFGRzNQaGhJQ2hFU2xna1gwQXlRSHV0ZkwzTmhGTFU5VAo1MU9RSFoyUTBG
 NUo5cFgxY0JPSlR5WHNwUHppLzhUdWdWcHNqcC9LdVpWbjg2WjhIVksraFhIWCs5bVV0emZy
 CnQweG91RGJRUHFlN1hRbDBJdnJpVVpaTWhFOXdOMEpMRHljTFhlLzl5RFppRGFsRUV0RENR
 ZXBpcGx2STdMRlQKRGw3cHArU2xKQWFNMm9RbFRQUGg3a2M4ZThwWnNmQUo2clZKTTlheFUr
 am0rNFRacFdSUm8rK3NIY00xY2VnZQo5MVI3VnRkREN6cGJRYys3Ymtpa3VHRk9sYkw5OFY5
 U2daWVVxWkQrbkI0MC9xeldxQkM5RGU5YWdZWUMxaFhWCmo2YnUvTHhOV0NYZis2YnpKVWJN
 aWZJc2JBNWhKZzRTbTlVTGFCV0M3eE1WUzFjSE9TSU9iaFl1aVU1Ny9HekkKRW5SMVo5YjU1
 UHYwV3IwelJjRW9aM3dSUG5hMzZ4bHU5YXRiSXBuRFQ1VTNSclB1TTdXWWdnWEZaMDRkMm5F
 TQpndnpYZk5BR2IvMG51K1kxZmwrbjJDYkJIenFleGFTckpYQUw3QjlBbmhock1ETGJxMk51
 aVk0dnk5YWFDTFZFCnZvcWpKRzBFQXJacG1BMkt4UG03ZmQrNWJNY1hsb2RsZEFiL3VRSU5C
 RnNFa2FzQkVBRGY1SlYwRWxST0dNL0gKOG5rYmdEVjEzYThwVkZHbXRiNm5JblJjTnMydEZV
 NFNmR3ZlaVRQWVhnZTJEdmFoUXZDdzF5NEthQVhFT1hFZwpVeUszTmtCWnU0dCtyMFZIdXlk
 cGJjOHlXU1BqaDU3T3JkNlpoZFcvY0xlVnpveTUwQTZxUkFvM05xVEpvRC9wCncxV1ZDZFdh
 dWx5MmtVZTFRMktoNks4ejBoNEkvbmF4eE1memlwNUZtaCthZDUxemNVREVvd24wNW1MZ3lL
 S0MKeDM4T0hPRlNwc0I0K3NJeVZCQ3d6OGRkSTJ6YXFnd3JjR2pxVndmTlh1cklqM0RYMjJZ
 V2k1ZlRwUXVjQUF6VgowbGx3SlF2ZlVVdTFvaXNadHhjRDczMXJ4MlU1UnZyeXVQMzBmZFhm
 TU9NbXh3TUdBbmFiT0s2NUwrZG9iODByCjVGV0ZXSGNxcTFXSUxyYWNhQURXMUxWb3NwbnNv
 TjdMTzdnV0lUWnNJK0hwdmdpVWhDS1BPckJQSThtMzdReTUKL1lWakdLdjBiQ0F5ZFdvbjk5
 aHBQcnZWRUp4U3VTcmFTdFhOMGVyOGRmc0R3Zko5KzF3RXdTM2pKa20zOXRudQp2TEpZbncr
 VkFrL2NjYXJQNkdrZWJDdkNZbUNQbEZ1YVMxVXpEZEVBU0trbXNRY1BWRHZBaUU4MWluTG9V
 akFXClVQSENsUkE1UmdZUmxqREQwdEZtSnFrM1FWNE53V25vSlF4R0FrZmJobERNV1R3bmsz
 ZzhETm1zaGw5QnRydlYKc01EUGYzVFk4TzNycXFJaUliYWE1TnQzeDRoNExQSDFIRmFFT1pC
 eVhOZWZsYkY4OVRxWFFUMDJBczBXZzBLbQprdHBQUFpMOGJIQm5PdEoyNHd0OVdXRW84T08v
 WVFBUkFRQUJpUUlsQkJnQkFnQVBCUUpiQkpHckFoc01CUWtCCjRUT0FBQW9KRVBKUEl5MFFp
 enJVd3VvUC8yOHhjdEdGN25EcWdFcTR2UzJQNEtFdUdSQVF6cnBEczdpNnRhYSsKWHpKLzlP
 RTJMVDh2SjBZQmhyQUpSYTUzYW1GbzZEaThmUWhTOVNHVXNORnhoell4MS9BbUx4cVB3YnRn
 TDg1UQpyREFVTjlqSmozTWlUVUxuSmVmb3VLQ1NNNHZRL0pnalF3emFDVHJpMzg4cjVHZkx5
 UFBwQ1BCbmdBeXloT21qCnIzd3RKaExzdHk4NFJPbjdmTFBRdGkyUTgvZm9XcWdiYUc1Mk9I
 VFhrYVFOSWdkWnlTaTNoTWxjcnc0NGM2NHIKQlRQWisxNGF3VjR6aHVaT0lDc0pGZXdDUkZh
 alJWc0RxRStLY3JSbXYvRXMxSmdqSDNnaGQ3bXIwaEpsenB4Ngo1YktLeFd4Um5GU0Fra2JJ
 MUs5ZGZESGpPaEpMc0ZmSk9qdXpLT2twM1QyZUVJdmRBWis0ZTZBbi9YOE1KbzIwCnBTN1lM
 NnRSN1ZUSHIrcTE0SlZTd0F6NXNOOE1GRCs5TFcyZktmMDVVRk01bXBlOEtFdmgvNHdBM1pi
 Q3ovNHUKWEhBT29ZeGZwZ0w5a0ZZem5wY1lDa3ZYT1AzZWZLREZzM3l6ekplcW94QTJDRk9Q
 Q1AwaXJKbzFCd283OEN5VgpLWVdWYnBGZlBWaEVOUGlaSXAwQ2lCdDBPcWFDNFp6VG1SUm81
 S1NwSnZSc3ZmaUpEOTJiZy9KWEdOSVpJTkd2CnhOQTZOQWJQU3RJU0hwRDR0bjNOR1cyU1lR
 eVIyVEpaQm5pMWl3RnRDL1pOVDYwSjhvd2hRSm52RVFlNitNQXAKa2lhejBTdXpmTlZMNDl4
 R3YyTHFhOHkxczB5NTgvMHpCTEhzK3F3ZTYvODlaMmdqZTdCcWZGak9UVVpNc0FzeQp6TGFK
 aVFJOEJCZ0JBZ0FtQWhzTUZpRUVXMzNGalpEK3dlbVFveEM2OGs4akxSQ0xPdFFGQWw1OUhN
 a0ZDUVZaCnZwNEFDZ2tROGs4akxSQ0xPdFFPeGcvNkFqWWoxUlFHL25yTktBNFQ5cnYrV2tr
 MFo1dXRqTERYa2NmQjV2TTgKa0ZwMCtTTnBWMmVRMmlRTTZXWTRCUVBweTBZTXVuSGVOVmJ5
 SHVPZzI2UEluUGc0WWdSZXpvUXhIbmdBdHJqLwowV1BKSXhodHRoWXNSODRhbXZ0TEJ3MWFs
 T3VRU1daQVNYRUdFcmgrTkQrNFB0N0dobWxEODhROWxmWXpGZHhJCk43V1YxdFBBVHBQeCta
 M1ljTllaWGQydkswVmluTG9odk4wdW1iOGd2ZUZDVkhYaWliYjZzcFI4Q0VQTVRvSEkKc1JU
 VWo1S3JEWmhmbUduY0Qrc0NySFNXVDlSbHh2TkZpRjI5RFdzKzdudUJCYU5QQ3hYMHozeTZJ
 aVg0aFVsaApkcUFOeVR1cHVSaVlGUFpIWjBMSFFzeDQ2WjJjVXE1enQwMUJwV1NCWHlKeEJj
 TVY3SGtWT2J3ZzJaTVJGbGNJCkRGYy9aWTBWbmlmSDlWRHFpaWZKelhtNUkxaWE1SXU2R3M2
 ZXRlZnZGdHQ2QlFKcXd0MlBNcENDOG53dDE3eDEKVlFuZVk4OVZmTTROczlPeC9IU01zODFZ
 U2wyKzZDSXQxVjVNeGtMYzMxeEJCNXZKTUhsRTRFM0g3VnVidjRicQoyWUxnY29nSlN6WkZv
 ZDRQUHY1ZkIzbTYybjV3U1R6M2todjBiVVhGOUN2dUxLNkk0dXdpUnBCNHhLRlRSZjZTCm5m
 RTNzaUcwVWlidFl1cE1wLzJ5RmYrWUpiVVlEZk1XUjhwZWNTRzFJemVjQ3dFNHptU2F6TFN3
 czFMc1pYQnAKUVd5U0JvaVBCeEU1akYzOEYvRkRyMll4VEdqNU1KaXRzTUloNkFoZnlCNG1o
 OW8yVzBlYnh4K2YyNXh4aGZydwpuekk9Cj16T0twCi0tLS0tRU5EIFBHUCBQVUJMSUMgS0VZ
 IEJMT0NLLS0tLS0K
Message-ID: <6bd0f6ff-9c99-d5c8-f6ae-7f604ad3e273@purse.io>
Date: Fri, 8 May 2020 12:33:55 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.7.0
MIME-Version: 1.0
In-Reply-To: <CAO3Pvs8rkouxQY912VW04pmn-hdAhMNL_6E_nXDmkeibBegwkA@mail.gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Content-Language: en-US
Cc: "lightning-dev\\\\@lists.linuxfoundation.org"
 <lightning-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] [Lightning-dev] On the scalability issues of
 onboarding millions of LN mobile clients
Precedence: list

On 5/5/20 5:31 PM, Olaoluwa Osuntokun via bitcoin-dev wrote:

> Hi Antoine,
>
>> Even with cheaper, more efficient protocols like BIP 157, you may have=
 a
>> huge discrepancy between what is asked and what is offered. Assuming 1=
0M
>> light clients [0] each of them consuming ~100MB/month for filters/head=
ers,
>> that means you're asking 1PB/month of traffic to the backbone network.=
 If
>> you assume 10K public nodes, like today, assuming _all_ of them opt-in=
 to
>> signal BIP 157, that's an increase of 100GB/month for each. Which is
>> consequent with regards to the estimated cost of 350GB/month for runni=
ng
>> an actual public node
> One really dope thing about BIP 157+158, is that the protocol makes ser=
ving
> light clients now _stateless_, since the full node doesn't need to perf=
orm
> any unique work for a given client. As a result, the entire protocol co=
uld
> be served over something like HTTP, taking advantage of all the establi=
shed
> CDNs and anycast serving infrastructure, which can reduce syncing time
> (less latency to
> fetch data) and also more widely distributed the load of light clients =
using
> the existing web infrastructure. Going further, with HTTP/2's server-pu=
sh
> capabilities, those serving this data can still push out notifications =
for
> new headers, etc.

The statelessness of compact block filters does look useful. Bloom
filters for
blocks can be inefficient, during a scan with a BIP37 wallet, it's
necessary to
discard already received merkle blocks as the filter has been updated
and the
previous results may have missed transactions. Both bitcoinj [1] and
breadwallet-core [2] handle it using a similar method. The alternative of=

synchronizing and alternating between requesting blocks and filter
updates leads
to slow scan times. With compact block filters, a separate wallet
process (from
the full node) can make adjustments necessary to what it needs to filter
without
having to communicate with the full node.

[1]:
https://github.com/bitcoinj/bitcoinj/blob/806afa04419ebdc3c15d5adf065979a=
a7303e7f6/core/src/main/java/org/bitcoinj/core/Peer.java#L1076-L1079
[2]:
https://github.com/breadwallet/breadwallet-core/blob/8eb05454df3e2d5cca24=
8b4e24eeffa420c97e3a/bitcoin/BRPeer.c#L83-L85