IBFT config options (#861)

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

docs/Consensus-Protocols/IBFT.md

@@ -23,7 +23,7 @@ To use IBFT 2.0 requires an IBFT 2.0 genesis file. The genesis file defines prop
       {
         "config": {
           ...
-          "revisedibft": {
+          "ibft2": {
             "blockperiodseconds": 2,
             "epochlength": 30000,
             "requesttimeoutseconds": 10
@@ -76,6 +76,16 @@ Properties that have specific values in IBFT 2.0 genesis files are:
 
 To start a node on an IBFT 2.0 private network, use the [`--genesis-file`](../Reference/Pantheon-CLI-Syntax.md#genesis-file`) option to specify the custom genesis file. 
 
+### Optional Configuration Options 
+
+Optional configuration options that can be specified in the genesis file are:  
+
+* `messageQueueLimit` - Default is 1000. In very large networks with insufficient resources increasing the message queue limit 
+   may help to deal with message activity surges.  
+   
+* `duplicateMesageLimit` - Default is 100. If seeing messages being retransmitted by the same node, increasing the duplicate message limit 
+   may reduce the number of retransmissions. A value of 2 to 3 times the number of validators is generally sufficient.  
+
 ## Adding and Removing Validators
 
 To propose adding or removing validators using the JSON-RPC methods, enable the HTTP interface 

docs/Consensus-Protocols/Overview-Consensus.md

@@ -44,7 +44,7 @@ The genesis file specifies the consensus protocol for a chain `config`:
 {
   "config": {
     ....
-    "revisedibft": {
+    "ibft2": {
       ...     
    }
   },