Replace s2s join sequence diagram for legibility
Without the vertical lines it's a bit difficult to parse. A different tool was used to generate the graph this time.
@@ -678,22 +678,49 @@ candidate may be used at each time. Thus, any join handshake can
potentially involve anywhere from two to four homeservers, though most
in practice will use just two.
-```
- Client Joining Directory Resident
- Server Server Server
+<!--
+https://textart.io/sequence
+
+object Client JoiningServer DirectoryServer ResidentServer
+Client->JoiningServer: join request
+JoiningServer->DirectoryServer: directory request
+DirectoryServer->JoiningServer: directory response
+JoiningServer->ResidentServer: make_join request
+ResidentServer->JoiningServer: make_join response
+JoiningServer->ResidentServer: send_join request
+ResidentServer->JoiningServer: send_join response
+JoiningServer->Client: join response
+-->
- join request -->
- |
- directory request ------->
- <---------- directory response
- |
- make_join request ----------------------->
- <------------------------------- make_join response
- |
- send_join request ----------------------->
- <------------------------------- send_join response
- |
- <---------- join response
+```
++---------+ +---------------+ +-----------------+ +-----------------+
+| Client | | JoiningServer | | DirectoryServer | | ResidentServer |
++---------+ +---------------+ +-----------------+ +-----------------+
+ | | | |
+ | join request | | |
+ |---------------------->| | |
+ | | | |
+ | | directory request | |
+ | |---------------------------->| |
+ | | | |
+ | | directory response | |
+ | |<----------------------------| |
+ | | | |
+ | | make_join request | |
+ | |------------------------------------------------>|
+ | | | |
+ | | |make_join response |
+ | |<------------------------------------------------|
+ | | | |
+ | | send_join request | |
+ | |------------------------------------------------>|
+ | | | |
+ | | |send_join response |
+ | |<------------------------------------------------|
+ | | | |
+ | join response | | |
+ |<----------------------| | |
+ | | | |
```
The first part of the handshake usually involves using the directory
