docs: updated chainHub sections

main/guides/orchestration/getting-started/key-concepts.md

@@ -1,6 +1,6 @@
 # Orchestration Key Concepts and APIs
 
-This document provides an overview of the fundamental concepts involved in building orchestration smart contracts, focusing on Orchestrator Interface, Orchestration Accounts, ChainHub, and Interchain Accounts (ICA).
+This document provides an overview of the fundamental concepts involved in building orchestration smart contracts, focusing on Orchestrator Interface, Orchestration Accounts, and ChainHub.
 
 
 ## Orchestrator Interface
@@ -32,7 +32,7 @@ See [getBrandInfo](https://agoric-sdk.pages.dev/interfaces/_agoric_orchestration
 const brandInfo = orchestrator.getBrandInfo('denom');
 ```
 
-- `asAmount`converts a denom amount to an `Amount` with a brand. See [asAmount](https://agoric-sdk.pages.dev/interfaces/_agoric_orchestration.Orchestrator#asAmount).
+- `asAmount` converts a denom amount to an `Amount` with a brand. See [asAmount](https://agoric-sdk.pages.dev/interfaces/_agoric_orchestration.Orchestrator#asAmount).
 
 ```javascript
 const amount = orchestrator.asAmount({ denom: 'uatom', value: 1000n });
@@ -81,15 +81,43 @@ await orchestrationAccount.deposit(payment);
 
 ## ChainHub
 
-The `makeChainHub` utility manages the connections and metadata for various blockchain 
-networks. It creates a new `ChainHub` instance implementing the [`ChainHubI`](https://github.com/Agoric/agoric-sdk/blob/000693442f821c1fcea007a2df740733b1f75ebe/packages/orchestration/src/exos/chain-hub.js#L70-L80C4) interface.
-
-It simplifies accessing and interacting with multiple chains, providing a unified interface
- for the orchestration logic to manage cross-chain operations effectively.
-ChainHub also allows dynamic registration and use of chain and connection information.
+ChainHub is a centeralized registry of chains, connections, and denoms 
+that simplifies accessing and interacting with multiple chains, providing
+a unified interface for the orchestration logic to manage cross-chain
+operations effectively. A chainHub instance can be created using a call
+to `makeChainHub` that makes a new ChainHub in the zone (or in the heap
+if no [zone](/glossary/#zone) is provided). The resulting object is an [Exo](/glossary/#exo) singleton.
+It has no precious state. Its only state is a cache of queries to
+`agoricNames` and the info provided in registration calls. When you
+need a newer version you can simply make a hub and repeat the registrations.
+ChainHub allows dynamic registration and use of chain and connection
+information using the following API.
+
+
+### Registration APIs
+
+- `registerChain` register a new chain with `chainHub`. The name will override
+a name in well known chain names. If a durable zone was not provided,
+registration will not survive a reincarnation of the vat, and will have to be
+registered again.
+- `registerConnection` registers a connections between two given chain IDs.
+- `registerAsset` registers an asset that may be held on a chain other than
+the issuing chain. Both corresponding chains should already be registered
+before this call.
+
+### Information Retrieval
+
+- `getChainInfo` takes a chain name to get chain info.
+- `getConnectionInfo` returns `Vow<IBCConnectionInfo>` for two given chain IDs. 
+- `getChainsAndConnection` is used to get chain and connection info give primary and counter chain names.
+- `getAsset` retrieves holding, issuing chain names etc. for a denom.
+- `getDenom` retrieves denom (string) for a `Brand`.
+
+In the below example, `chainHub` is used to register a new chain and establish a connection 
+between the Agoric chain and the newly registered chain.
 
 ```javascript
-const chainHub = makeChainHub(remotePowers.agoricNames);
+const chainHub = makeChainHub(privateArgs.agoricNames, vowTools);
 
 // Register a new chain with its information
 chainHub.registerChain(chainKey, chainInfo);
@@ -101,51 +129,3 @@ chainHub.registerConnection(
   connectionInfo,
 );
 ```
-
-In this example, `chainHub` is used to register a new chain and establish a connection 
-between the Agoric chain and the newly registered chain.
-
-## Interchain Account (ICA)
-
-[Interchain Accounts](/glossary/#interchain-account-ica) (ICAs) are an IBC feature utilized 
-within Agoric’s Orchestration API. They enable an Agoric smart contract to control an
- account on another blockchain in the Cosmos ecosystem. The [Inter-Blockchain Communication (IBC)](/glossary/#ibc) protocol facilitates seamless interactions and transactions across 
- different blockchains.
-
-#### Benefits of ICAs
-- **Cross-chain Control**: ICAs allow a contract to manage accounts on other chains, 
-treating them like any other (remotable) object.
-- **Access Control**: Only the contract that creates the ICA has full control over it but 
-can delegate specific access permissions to clients.
-
-For more details on access control, refer to [Access Control with Objects](/guides/zoe/contract-access-control).
-
-
-### Example: ICA Usage in a Smart Contract
-
-Here’s an example of ICA usage from one of the [sample contracts](https://github.com/Agoric/agoric-sdk/blob/master/packages/orchestration/src/examples/swapExample.contract.js):
-
-```javascript
-const stakeAndSwapFn = async (orch, ...) => {
-  const omni = await orch.getChain('omniflixhub');
-  const agoric = await orch.getChain('agoric');
-
-  const [omniAccount, localAccount] = await Promise.all([
-    omni.makeAccount(),
-    agoric.makeAccount(),
-  ]);
-
-  const omniAddress = omniAccount.getAddress();
-
-  // Deposit funds from user seat to LocalChainAccount
-  const transferMsg = orcUtils.makeOsmosisSwap({ ... });
-
-  try {
-    await localAccount.transferSteps(give.Stable, transferMsg);
-    await omniAccount.delegate(offerArgs.validator, offerArgs.staked);
-  } catch (e) {
-    console.error(e);
-  }
-};
-```
-