feat: host (#296)

content/concepts/introduction/core-abstractions/_index.md

@@ -1,5 +1,5 @@
 ---
 title : "Core Abstractions"
 description: "Learn about the core pillars that compose each libp2p peer and a libp2p network."
-weight: 4
+weight: 5
 ---

content/concepts/introduction/host.md

@@ -0,0 +1,24 @@
+---
+title: "libp2p Host"
+description: "A libp2p host is a program or process that runs on a peer and allows it to participate in a libp2p network."
+weight: 4
+---
+
+A libp2p host is a program or process that allows a peer to participate
+in the libp2p network.
+
+{{< alert icon="" context="note">}}
+There are [several implementations](https://libp2p.io/implementations/) of the
+libp2p host, and not all of the implementations support the features mentioned below.
+{{< /alert >}}
+
+A libp2p host has a
+[unique identity](/concepts/introduction/core-abstractions/peers#peer-id)
+and can listen on different [transport protocols](/concepts/transports/overview),
+[dial connections to other hosts](/concepts/transports/listen-and-dial), and detect
+if it's a publicly reachable node or if it's behind a NAT/firewall with
+[AutoNAT](../nat/overview.md##automatic-router-configuration).
+The host can apply [hole punching techniques](/concepts/nat/hole-punching) to overcome
+NATs, find peers through a routing protocol like
+[DHT](/concepts/introduction/protocols/dht), and send messages across the network
+using [Gossipsub](/concepts/pubsub/gossipsub).

content/concepts/introduction/protocols/_index.md

@@ -1,5 +1,5 @@
 ---
 title : "Protocol Basics"
 description: "Learn about the core pillars that compose each libp2p peer and a libp2p network."
-weight: 4
+weight: 6
 ---