introduce eager links

1 files changed, 6 insertions, 0 deletions

diff --git a/docs/glossary.md b/docs/glossary.md
index 71d3014..050a885 100644
--- a/docs/glossary.md
+++ b/docs/glossary.md
@@ -103,6 +103,12 @@ closest by round-trip time first.
 **relay**: in a partial mesh, a node announces new heads to its neighbours, which pull
 the changes they lack.
 
+**eager link** and **lazy link**: over a lazy link, changes are announced and pulled
+(the relay); over an eager one, a neighbour gets them as sync messages as soon as the
+other end applies them. A pull that brought changes makes a link eager in that
+direction, changes that came first another way make it lazy again (Plumtree's GRAFT and
+PRUNE).
+
 **blob**: bytes too large for one message, fetched in chunks from several peers at once:
 an epoch's snapshot change (for a rejoining node) or a remake's content (for voters).