Revise glossary entry for kube-proxy (#15172)

- Mark as relevant to networking.
- Unmark as a core object. kube-proxy is not an API object.
- Fix hyperlink to reference docs.
- Include hyperlink in definition. This is used in /docs/concepts/overview/components/
- Revise wording.

content/en/docs/reference/glossary/kube-proxy.md

@@ -2,21 +2,24 @@
 title: kube-proxy
 id: kube-proxy
 date: 2018-04-12
-full_link: /docs/reference/generated/kube-proxy
+full_link: /docs/reference/command-line-tools-reference/kube-proxy/
 short_description: >
   `kube-proxy` is a network proxy that runs on each node in the cluster.
 
-aka: 
+aka:
 tags:
 - fundamental
-- core-object
+- networking
 ---
- `kube-proxy` is a network proxy that runs on each node in the cluster.
+ [kube-proxy](/docs/reference/command-line-tools-reference/kube-proxy/) is a
+network proxy that runs on each node in your cluster, implementing part of
+the Kubernetes {{< glossary_tooltip term_id="service">}} concept.
 
-It enables the Kubernetes service abstraction by maintaining network rules on
+<!--more-->
-the host and performing connection forwarding.
 
-<!--more--> 
+kube-proxy maintains network rules on nodes. These network rules allow
-
+network communication to your Pods from network sessions inside or outside
-`kube-proxy` is responsible for request forwarding. `kube-proxy` allows TCP and UDP stream forwarding or round robin TCP and UDP forwarding across a set of backend functions.
+of your cluster.
 
+kube-proxy uses the operating system packet filtering layer if there is one
+and it's available. Otherwise, kube-proxy forwards the traffic itself.