Mhairi
March 3, 2022, 3:35pm
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This UMIP will have the effect of registering an oracle hub contract that will enable the optimistic oracle deployed on non-mainnet EVM networks to make cross-chain price requests to the DVM on mainnet Ethereum.
## Headers
| UMIP-144 | |
|------------|--------------------------------|
| UMIP Title | Register Oracle Hub |
| Authors | Nick Pai (nick@umaproject.org) |
| Status | Last Call |
| Created | January 10, 2022 |
# Summary (2-5 sentences)
This UMIP will have the effect of registering an oracle hub contract that will enable the optimistic oracle deployed on non-mainnet EVM networks to make cross-chain price requests to the DVM on mainnet Ethereum.
# Motivation
[This audit](https://blog.openzeppelin.com/uma-audit-phase-6/) includes a hub and spoke architecture that UMA can use to broadcast messages between mainnet, where the DVM is deployed, and other EVM networks. The hub collects messages sent between an "oracle spoke" deployed on any non-mainnet EVM networks and the DVM on mainnet, and therefore it must be approved to submit price requests to the DVM. It might be helpful to review [this UMIP](https://github.com/UMAprotocol/UMIPs/blob/master/UMIPs/umip-113.md) that approved an "oracle root tunnel" that specifically sent messages between Polygon and Ethereum. The oracle hub is similar to the root tunnel except that it can be used for other EVM networks besides Polygon and it can communicate with many networks at the same time, hence why its referred to as an N-to-1 "hub" and not a 1-to-1 "tunnel".
# Cross Chain Infrastructure
[This folder](https://github.com/UMAprotocol/protocol/tree/34f3180b48397a2ba9211cc6fae33a327b9cb165/packages/core/contracts/cross-chain-oracle) contains contracts that are built on top of bridge protocols to enable UMA's Optimistic Oracle and
Governance contracts to send messages across EVM networks.
## Hub and Spoke Architecture
*Hub and *Spoke contracts are included that are respectively deployed on "Parent" and "Child" networks. As the Hub
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