LL's grid had a constant stream of UseCircuitCode packets, this is the output from litesim (don't have a convinent opensim-based grid right now):

Here's the client output:
DEBUG [Test User]: Resending packet #2 (libsecondlife.Packets.CompleteAgentMovementPacket), 4009ms have passed
DEBUG [Test User]: Resending packet #3 (libsecondlife.Packets.AgentUpdatePacket), 4009ms have passed
DEBUG [Test User]: Resending packet #4 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4009ms have passed
INFO [Test User]: Received a region handshake for Litesim welcome (209.126.144.49:9000)
DEBUG [Test User]: Resending packet #40 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4010ms have passed
DEBUG [Test User]: Resending packet #57 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4335ms have passed
DEBUG [Test User]: Resending packet #23 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4010ms have passed
DEBUG [Test User]: Resending packet #1 (libsecondlife.Packets.UseCircuitCodePacket), 4011ms have passed
DEBUG [Test User]: Resending packet #2 (libsecondlife.Packets.CompleteAgentMovementPacket), 4010ms have passed
DEBUG [Test User]: Resending packet #3 (libsecondlife.Packets.AgentUpdatePacket), 4010ms have passed
DEBUG [Test User]: Resending packet #4 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4010ms have passed
INFO [Test User]: Received a region handshake for Litesim welcome (209.126.144.49:9000)
DEBUG [Test User]: Resending packet #74 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4341ms have passed
DEBUG [Test User]: Resending packet #40 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4009ms have passed
DEBUG [Test User]: Resending packet #57 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4009ms have passed
DEBUG [Test User]: Resending packet #23 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4008ms have passed
DEBUG [Test User]: Resending packet #1 (libsecondlife.Packets.UseCircuitCodePacket), 4009ms have passed
DEBUG [Test User]: Resending packet #2 (libsecondlife.Packets.CompleteAgentMovementPacket), 4009ms have passed
DEBUG [Test User]: Resending packet #3 (libsecondlife.Packets.AgentUpdatePacket), 4009ms have passed
DEBUG [Test User]: Resending packet #4 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4009ms have passed
INFO [Test User]: Received a region handshake for Litesim welcome (209.126.144.49:9000)
DEBUG [Test User]: Resending packet #74 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4007ms have passed
DEBUG [Test User]: Resending packet #40 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4007ms have passed
DEBUG [Test User]: Resending packet #91 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4336ms have passed
DEBUG [Test User]: Resending packet #57 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4007ms have passed
DEBUG [Test User]: Resending packet #23 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4007ms have passed
DEBUG [Test User]: Resending packet #1 (libsecondlife.Packets.UseCircuitCodePacket), 4009ms have passed
DEBUG [Test User]: Resending packet #2 (libsecondlife.Packets.CompleteAgentMovementPacket), 4009ms have passed
DEBUG [Test User]: Resending packet #3 (libsecondlife.Packets.AgentUpdatePacket), 4009ms have passed
DEBUG [Test User]: Resending packet #4 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4009ms have passed
INFO [Test User]: Received a region handshake for Litesim welcome (209.126.144.49:9000)
DEBUG [Test User]: Resending packet #74 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4011ms have passed
DEBUG [Test User]: Resending packet #40 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4011ms have passed
DEBUG [Test User]: Resending packet #91 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4011ms have passed
DEBUG [Test User]: Resending packet #57 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4010ms have passed
DEBUG [Test User]: Resending packet #23 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4010ms have passed
DEBUG [Test User]: Resending packet #108 (libsecondlife.Packets.RegionHandshakeReplyPacket), 4344ms have passed


Server console:
Wow, a client finished connecting! Give 'em some content
Created layerdata packets!
Wow, a client finished connecting! Give 'em some content
Wow, a client finished connecting! Give 'em some content
Created layerdata packets!
Created layerdata packets!
Wow, a client finished connecting! Give 'em some content
Wow, a client finished connecting! Give 'em some content
Wow, a client finished connecting! Give 'em some content
Created layerdata packets!
Created layerdata packets!
Created layerdata packets!
New circuit request for agent ab685bcb-0811-4eb0-ba0b-a895079b565f

>>> New agent: ab685bcb-0811-4eb0-ba0b-a895079b565f
Wow, a client finished connecting! Give 'em some content
Created layerdata packets!
Wow, a client finished connecting! Give 'em some content
Created layerdata packets!
Wow, a client finished connecting! Give 'em some content
Wow, a client finished connecting! Give 'em some content
Wow, a client finished connecting! Give 'em some content
Created layerdata packets!
Wow, a client finished connecting! Give 'em some content
Created layerdata packets!
Wow, a client finished connecting! Give 'em some content
Wow, a client finished connecting! Give 'em some content