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+# Upgrade to binary pongs
+
+### Motivation
+
+The current intra-peer protocol is JSON, which means messages need to be ascii-armored.  This is not as optimal as a binary protocol, especially when sending large blobs like I2P destinations.
+
+### Upgrade path
+
+The pinging node sends pings with the `version` field set to 2.
+
+Upon receiving pings with version 2, the responding node will send a binary Pong.  
+
+### Pong format:
+
+```
+byte 0: message type, fixed at 1 for "Pong"
+byte 1: version, fixed at 2
+bytes 2-18: UUID of the Pong
+byte 19: number of destinations contained in this Pong
+bytes 20-end: destinations
+```
+
+### Other benefits
+
+With the reduced size of Pong messages each Pong can carry more destinations.  Also, the default maximum number of connections can be increased.