> ## Documentation Index
> Fetch the complete documentation index at: https://cts-docs.cosmos.network/llms.txt
> Use this file to discover all available pages before exploring further.

# How IBC Works

> A high-level view of light clients, connections, channels, and packets.

This page covers enough of the protocol to reason about a deployment. For the
full specification and developer material, see the
[Inter-Blockchain Communication documentation](https://docs.cosmos.network/ibc/latest/intro).

## Light clients

A light client is an on-chain component that tracks a counterparty chain's
consensus state. Each chain runs a light client of the other. The tracked state
lets each chain verify that something occurred on the other chain without
trusting anyone to report it.

Light clients form the foundation of the trust model: the chains verify
cryptographic proofs themselves, with no external attestor.

## Connections and channels

A connection is a link between two light clients that establishes mutual
verification between their chains. A channel is an application traffic path
established on top of a connection. A single connection can support many
channels.

### Why the separation exists

The separation matters operationally: the expensive trust-establishing step
happens once per counterparty. Individual applications then receive their own
channels on top of that connection.

## Packets and relayers

A packet is the data an application sends over a channel. The sending chain
commits the packet, the receiving chain accepts it, and an acknowledgment
returns.

A relayer is a permissionless transport role that carries packets between
chains. It cannot forge, alter, or censor a packet because the receiving chain
verifies every packet against its light client before acting. A misbehaving
relayer can cause only a delay, not an invalid state change.

## Timeouts

A timeout is a deadline carried by every packet. If the packet is not delivered
in time, the sending chain can prove the timeout and revert its side. The timeout
prevents assets from becoming stranded when a counterparty chain stalls or a
relayer stops.

## Related

* [Overview](/ibc/overview) for why this is not a bridge
* [Token Transfers](/ibc/token-transfers)
* [IBC documentation](https://docs.cosmos.network/ibc/latest/intro)