First pass up to configuration

Change-Id: Ifd82c38aa18d5216c5772a64d9d77046def005fe
diff --git a/specification.rst b/specification.rst
index f59ccc0..b2c502f 100644
--- a/specification.rst
+++ b/specification.rst
@@ -1,6 +1,8 @@
 Specification
 =============
 
+In the following we provide an exhaustive list of all features supported.
+
 SDN Features
 ------------
   - ONOS cluster of all-active N instances affording N-way redundancy and scale, where N = 3 or N = 5
@@ -33,8 +35,9 @@
 -----------
 IP connectivity
 
-  - IPv4 and IPv6 unicast routing (internal use of MPLS Segment Routing)
+  - IPv4 and IPv6 [#f1]_  unicast routing (internal use of MPLS Segment Routing)
   - Subnetting configuration on all non-spine facing leaf ports; no configuration required on any spine port
+  - Equal Cost Multi-Path (ECMP) for traffic across spine switches
   - IPv6 router advertisement
   - ARP, NDP, IGMP handling
   - Number of flows in spines greatly simplified by MPLS Segment Routing
@@ -73,17 +76,20 @@
 - Provide easy access for 3rd party edge application developers and for the Aether centralized management platform
 - Support for traffic redirecting, dropping, network slicing and QoS
 
-Programmability
----------------
-- Support for Stratum, P4Runtime and gNMI and P4 programs
-- Innovative services enabled by programmable pipeline
-  - 4G/5G UPF - GTP encap/decap, idle-mode buffering, QoS and more
-  - BNG - PPPoE, anti-spoofing, accounting and more
+Data Plane Programmability
+--------------------------
+- Support for Stratum, P4Runtime/gNMI, and P4 programs
+- Innovative services enabled by programmable data plane:
+
+  - 4G/5G User Plane Function (UPF): GTP encap/decap, usage reporting, downlink buffering and data notifications,
+    QoS and more, with integration with mobile core control plane via PFCP protocol (3GPP standard interface).
+  - Inband Network Telemetry (INT): INT-XD mode with support for flow reports, drop reports,
+    queue congestion reports, with smart filters to reduce volume of reports ingested by the INT collector.
 
 Troubleshooting & Diagnostics
 -----------------------------
-- T3: Troubleshooting tool to diagnose broken forwarding paths fabric wide
-- ONOS-diags: One-click Diagnostics collection tool
+- T3: Troubleshooting tool to diagnose broken forwarding paths fabric wide (work in progress)
+- ONOS-diags: One-click diagnostics collection tool for issue reporting
 
 .. _Topology:
 
@@ -104,14 +110,14 @@
 
 Single Leaf Pair (Dual-Homing)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Compared to single switch, it provides more redundancy in terms of server NIC failure and link failure.
+Compared to a single switch, it provides redundancy in terms of server NIC failure and link failure.
 
 .. image:: images/topology-pair.png
   :width: 225px
 
 Leaf-Spine (without pairing)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Compared to single switch, it offers more redundancy in terms of switch failure and provides better scalability.
+Provide horizontal-scalability for multi-rack deployments, with redundancy for spine switch failures:
 
 .. image:: images/topology-2x2.png
   :width: 300px
@@ -135,22 +141,21 @@
 
 Resiliency
 ----------
-Provides HA in following scenarios
+Provides HA in the following scenarios:
 
   - Controller instance failure (requires 3 or 5 node ONOS cluster)
-  - Link failures
-  - Spine failure
+  - Leaf-spine link failures
+  - Spine switch failure
 
-Further HA support in following failure scenarios with dual-homing enabled
+Further HA support in following failure scenarios with dual-homing enabled:
 
-  - Leaf failure
+  - Leaf switch failure
   - Upstream router failure
   - Host NIC failure
 
 Scalability
 -----------
 In Production
-
   - Up to 80k routes (with route optimization)
   - 170k Flows
   - 600 direct-attached hosts
@@ -158,22 +163,22 @@
   - 2 spine switches
 
 In Pre-Production
-
   - Up to 120k routes (with route optimization)
   - 250k flows
   - 600 direct-attached hosts
   - 8 leaf switches
   - 2 spine switches
-  - 5000 active UEs, 10 call per second
+
+4G/5G specific
+  - 5000 active UEs, 10 calls per second
 
 Security
 --------
-  - TLS-secured connection between controllers and switches (premium feature)
-  - AAA 802.1x authentication
+  - TLS-secured gRPC connection between controllers and switches (work-in-progress)
 
 Aether-ready
 ------------
-Fully integrated with Aether (5G/LTE private enterprise edge cloud solution)
+Fully integrated with Aether (5G/4G private enterprise edge cloud solution)
 including deployment automation, CI/CD, logging, monitoring, and alerting.
 
 Overlay Support
@@ -193,16 +198,26 @@
   - CPU: 32 Cores
   - RAM: 128GB RAM. 64GB dedicated to ONOS JVM heap
 
+Recommendation (per ONOS instance) for 5K UEs when enabling UPF:
+
+  - CPU: 1 Cores
+  - RAM: 4GB RAM
+
+
 White Box Switch Hardware
 -------------------------
 - Multi-vendor: APS Networks™, Dell™, Delta Networks™, Edgecore Networks™, Inventec™, Netburg™, QCT™
 - Multi-chipset:
-  - Intel Tofino (supports all features, including programmability, UPF & INT)
+  - Intel Tofino (supports all features, including UPF & INT)
   - Broadcom Tomahawk®, Tomahawk+®, Trident2 (traditional fabric features only)
-- 1/10G, 25G, 40G, 100G
+- 1/10G, 25G, 40G, and 100G ports
 - Refer to Supported Devices list in https://github.com/stratum/stratum for the most up-to-date hardware list
 
 White Box Switch Software
 -------------------------
 - Open source ONL, ONIE, Docker, Kubernetes
 - Stratum available from ONF
+
+.. rubric:: Footnotes
+
+.. [#f1] IPv6 support on the data plane (P4 program) is still work-in-progress.