add xversionkeys.md for central db for prefix/suffix info. add page refs

protocol/p2p/xupdate.md

@@ -1,6 +1,6 @@
 <div class="cwikmeta">{
 "title":"XUPDATE",
-"related":["/protocol","/protocol/p2p/xversion"]
+"related":["/protocol","/protocol/p2p/xversion" ,"/protocol/p2p/xversionkeys"]
 }</div>
 
 *Notifies peers about an XVERSION configuration value update*

protocol/p2p/xversion.md

@@ -1,6 +1,6 @@
 <div class="cwikmeta">{
 "title":"XVERSION",
-"related":["/protocol","/protocol/p2p/xupdate"]
+"related":["/protocol","/protocol/p2p/xupdate","/protocol/p2p/xversionkeys"]
 }</div>
 
 *Notifies peers about a protocol configuration value*
@@ -19,19 +19,8 @@ See [XVERSION specification](https://github.com/BitcoinUnlimited/BitcoinUnlimite
 
 XVERSION field identifiers are 32 bits and split into a 16 bit prefix and 16 bit suffix.  Each development group is assigned a prefix so that new identifiers do not accidentally conflict.  Once a field identifier is created by group A, it should be used by other software both to receive that information from A and to present that information to other software.  Therefore, group A **MUST NOT** change the syntax or semantics of a field once defined.  To change a field, create a new identifier and deprecate (by no longer using the original identifier).
 
-#### Prefix Assignments
+#### Prefix and Suffix Assignments
-|    Group          | Value |
+See [xversionkeys](/protocol/p2p/xversionkeys.md) for a full list of assigned prefixes and field definitions.
-|-------------------|-------|
-| Bitcoin ABC       |   0   |
-| Bitcoin Unlimited |   2   |
-
-
-#### Field Assignments
-
-See [xversionkeys.dat](https://github.com/BitcoinUnlimited/BitcoinUnlimited/blob/bucash1.7.0.0/src/xversionkeys.dat) for the most up-to-date field definitions defined by the BitcoinUnlimited full node.
-Note that:
-* *u64c* refers to a [compact int](/protocol/p2p/compact__int.md) serialization of an unsigned 64-bit value.
-* *Changeable* fields MAY be changed during the course of a connection via the [XUPDATE](/protocol/p2p/xupdate) message.
 
 ### Support
 

protocol/p2p/xversionkeys.md

@@ -0,0 +1,24 @@
+<div class="cwikmeta">{
+"title":"XVERSIONKEYS",
+"related":["/protocol","/protocol/p2p/xversion","/protocol/p2p/xupdate"]
+}</div>
+
+
+### Prefix Assignments
+|    Group                | Value |
+|-------------------------|-------|
+| Reserved for versioning |   0   |
+| Bitcoin Cash Node       |   1   |
+| Bitcoin Unlimited       |   2   |
+
+
+#### Field Assignments
+
+See [xversionkeys.dat](https://github.com/BitcoinUnlimited/BitcoinUnlimited/blob/bucash1.7.0.0/src/xversionkeys.dat) for the most up-to-date field definitions defined by the BitcoinUnlimited full node.
+Note that:
+* *u64c* refers to a [compact int](/protocol/p2p/compact__int.md) serialization of an unsigned 64-bit value.
+* *Changeable* fields MAY be changed during the course of a connection via the [XUPDATE](/protocol/p2p/xupdate) message.
+
+### Support
+
+Supported by: **Bitcoin Unlimited**