# How Bridges Improve L2 Composability by Georgios Gontikas | Devcon Bogotá

- Channel: [Devcon](https://streameth.org/devcon)
- Date: 2023-10-07
- Duration: 06:33
- Watch: https://streameth.org/watch/yt-43LXzRlJ77k
- YouTube: https://www.youtube.com/watch?v=43LXzRlJ77k

## Description

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https://archive.devcon.org/archive/watch/6/how-bridges-improve-l2-composability/

Two of the biggest arguments against L2s are that they are breaking composability and interoperability. DApps are deployed as stand-alone apps in each L2 with limited ability to communicate with each other. This leads to silos and several issues in terms of capital efficiency, governance, security, user experience and maintenance.
We will explore how bridges should become the interoperability layer that will connect all the protocol “silos” across L2s, by using secure message passing.

Speaker(s): Georgios Gontikas
Track: Layer 2s
Keywords: bridges,interoperability,L2

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Devcon is the Ethereum conference for developers, researchers, thinkers, and makers. 
Devcon 6 was held in Bogotá, Colombia on Oct 11 - 14, 2022.
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## Transcript

foreign [Music] georgius I do product for Sigma and I'm gonna talk to you about how bridges can improve well to composibility um so let's look at some numbers about the L2 growth so at the moment there are more than 20 Roll-Ups on top of ethereum and all the total value locked which is a good proxy for user adoption is like around 6 billion which is around one-fifth of what minute is so that shows like that is going quite well um and two of the most important Roll-Ups like Arboretum and Optimus respectively they have more than 160 dabs on top right however there are some side effects so all these protocols and apps are silos across all these Road Labs so the liquidity is fragmented and the end user experience across using all these roadlapses not so optimal so it looks like there is a trade-off between low fees and hydroelection throughput overcomposability so what is composability uh it's yeah in other words it's the money Legos like it's what fuel ethereum growth all these years and yes we can simply see here is uh on L1 uh how our yield aggregator can use the decks or how um uh Landing protocol can use a standard protocols I can build on top right and as you can see here L1 is yeah the risk composability another one and all these optimistic or ZK Road Labs different ones uh the there's also composability inside them but not across them right so that's the issue we just described um yeah so as an example these are four of the most popular protocols and we see that they are developed they are deployed on ethereum and the roll ups and yeah at least two of the road labs uh but all these deployments are separate from each other right they cannot communicate with each other there is no connection between them um so you can see the the L2 ecosystem is uh quite huge uh quite thriving with all these kind of apps like Dexys yield aggregators nft Marketplace synthetics but it's fragmented and here's an example use case from from a user perspective right so a user has some liquidity on curve let's say on arbitrary they want to move it to optimism to do that they need at least 13 transactions like wallet confirmations and they need to wait seven days for exiting the roll up and of course they need to pay the exit and the entry fees right on mainnet um what has been the uh the role of the bridges so far um apart from the canonical Bridges there are at least 10 bridges for uh roll-up hopping or this second um so we solved two of the problems so you don't have to wait seven days anymore and you don't have to pay the enter and exit fees but all these 2013 separate transactions still exist so what we propose is you know that the bruises should move away from uh just this year's C20 token bridging and focus more on message passing right so how do you pass messages from an L2 to another L2 or 12-1 and yeah the end game of that is yeah you can call them the cross roll up money Legos right so it's this is the same um diagram we showed before but now you can basically use a a decks on L1 um to communicate with uh derivatives protocol on an L2 right and and all these kind of um synergies over there um so yeah the the benefits of these cross roll up composibility from for the end user would be that they don't uh have to manually uh Bridge anymore for any kind of cross or lab transaction like a token swap or moving the liquidity or any kind of government governance actions like voting or Market making or money market transactions like lending or borrowing not having to move the collateral or nft marketplaces they can Market the market the the nfts whatever they want in wherever and L2 they want so how this could look like um so this is uh yeah our proposal like a cross roll up composibility layer and you can see on top is one uh imagine like one roll up on top and another roll up uh below and in the middle is the relay so it's basically off chain uh really a network and the main concept here is that you have a generic message passing smart contracts developed on both deployed on both roll ups and you have the so-called Adobe contract which will prepare and parse the necessary messages right so this uh the setup will help any smart controls for now from one up from one roll up to communicate with another roll up or even with uh layer one yeah so that was basically it let me talk yeah we can have some questions I don't know how much we have one just one question yeah yeah in case here's a question how does the relayer maintain uh L1 level of security like you mentioned I didn't mention that it maintains little one security but yeah there's several kind of setups right so you can you can have a fully trusted setup uh you can have a trust minimize setup with um you know kind of optimistic model or a ZK model so yeah I mean if you're we're talking for this specific uh proposal we're doing uh you know we're starting with a kind of controlled setup and we are exploring um like optimistically you know uh putting the state back on L1 or you know using ZK so this is something this still work in progress thank you so much big round of applause for your guys in Sigma