transport patch

diff --git a/RNS/Transport.py b/RNS/Transport.py
index 1453f78d..0af962da 100755
--- a/RNS/Transport.py
+++ b/RNS/Transport.py
@@ -3119,9 +3119,20 @@ class Transport:
                     return

                 # Forward path request on all interfaces
-                # except the requestor interface
+                # except the requestor interface.
+                # The discovery timeout must also cover a full round trip for an MTU on the slowest interface
+                discovery_timeout = Transport.PATH_REQUEST_TIMEOUT
+                for interface in Transport.interfaces:
+                    if search_mode_filter and not interface.mode in search_mode_filter: continue
+                    if not interface.online or interface == attached_interface: continue
+                    if interface.bitrate != None and interface.bitrate > 0:
+                        medium_timeout = 2*(RNS.Reticulum.MTU*8/max(interface.bitrate, RNS.Reticulum.MINIMUM_BITRATE)) + Transport.PATH_REQUEST_GRACE
+                        if medium_timeout > discovery_timeout: discovery_timeout = medium_timeout
+
                 RNS.log("Attempting to discover unknown path to "+RNS.prettyhexrep(destination_hash)+" on behalf of path request"+interface_str, RNS.LOG_PATHING) if RNS.sl(RNS.LOG_PATHING) else None
-                pr_entry = { "destination_hash": destination_hash, "timeout": time.time()+Transport.PATH_REQUEST_TIMEOUT, "requesting_interface": attached_interface }
+                pr_entry = { "destination_hash": destination_hash, "timeout": time.time()+discovery_timeout, "requesting_interface": attached_interface }
                 with Transport.discovery_pr_lock: Transport.discovery_path_requests[destination_hash] = pr_entry

                 for interface in Transport.interfaces: