Update Cilium description (#36040)

* Update Cilium description

* removing scalability comments per review

Co-Authored-By: Tim Bannister <[email protected]>

Co-authored-by: Tim Bannister <[email protected]>

Author: xmulligan

content/en/docs/concepts/cluster-administration/addons.md

@@ -19,7 +19,7 @@ This page lists some of the available add-ons and links to their respective inst
 * [Antrea](https://antrea.io/) operates at Layer 3/4 to provide networking and security services for Kubernetes, leveraging Open vSwitch as the networking data plane.
 * [Calico](https://docs.projectcalico.org/latest/introduction/) is a networking and network policy provider. Calico supports a flexible set of networking options so you can choose the most efficient option for your situation, including non-overlay and overlay networks, with or without BGP. Calico uses the same engine to enforce network policy for hosts, pods, and (if using Istio & Envoy) applications at the service mesh layer.
 * [Canal](https://projectcalico.docs.tigera.io/getting-started/kubernetes/flannel/flannel) unites Flannel and Calico, providing networking and network policy.
-* [Cilium](https://github.com/cilium/cilium) is a L3 network and network policy plugin that can enforce HTTP/API/L7 policies transparently. Both routing and overlay/encapsulation mode are supported, and it can work on top of other CNI plugins.
+* [Cilium](https://github.com/cilium/cilium) is a networking, observability, and security solution with an eBPF-based data plane. Cilium provides a simple flat Layer 3 network with the ability to span multiple clusters in either a native routing or overlay/encapsulation mode, and can enforce network policies on L3-L7 using an identity-based security model that is decoupled from network addressing. Cilium can act as a replacement for kube-proxy; it also offers additional, opt-in observability and security features.
 * [CNI-Genie](https://github.com/cni-genie/CNI-Genie) enables Kubernetes to seamlessly connect to a choice of CNI plugins, such as Calico, Canal, Flannel, or Weave.
 * [Contiv](https://contivpp.io/) provides configurable networking (native L3 using BGP, overlay using vxlan, classic L2, and Cisco-SDN/ACI) for various use cases and a rich policy framework. Contiv project is fully [open sourced](https://github.com/contiv). The [installer](https://github.com/contiv/install) provides both kubeadm and non-kubeadm based installation options.
 * [Contrail](https://www.juniper.net/us/en/products-services/sdn/contrail/contrail-networking/), based on [Tungsten Fabric](https://tungsten.io), is an open source, multi-cloud network virtualization and policy management platform. Contrail and Tungsten Fabric are integrated with orchestration systems such as Kubernetes, OpenShift, OpenStack and Mesos, and provide isolation modes for virtual machines, containers/pods and bare metal workloads.