diff --git a/rtio/sed/output_network.py b/rtio/sed/output_network.py
index 4308575..9e68987 100644
--- a/rtio/sed/output_network.py
+++ b/rtio/sed/output_network.py
@@ -172,6 +172,8 @@ class OutputNetwork(Elaboratable):
                 # - Not all outputs are valid
                 # - All channel numbers in the input appear exactly once as a
                 #   valid output
+                # - All valid outputs match an input modulo accounting
+                #   information
                 with m.Else():
                     m.d.comb += Assert(~channels_unique)
                     all_valid = Signal(reset=1)
@@ -188,6 +190,19 @@ class OutputNetwork(Elaboratable):
                                     accum = accum & ((Past(input_node.payload.channel, clocks=network_latency) != self.output[node2].payload.channel) | ~self.output[node2].valid)
                             input_channel_valid_once = input_channel_valid_once | accum
                         m.d.comb += Assert(input_channel_valid_once)
+                    for output_node in self.output:
+                        with m.If(output_node.valid):
+                            found_input = Signal()
+                            for input_node in self.input:
+                                match = Signal(reset=1)
+                                with m.If(Past(input_node.seqn, clocks=network_latency) != output_node.seqn):
+                                    m.d.comb += match.eq(0)
+                                for field, _ in layout_payload:
+                                    with m.If(Past(getattr(input_node.payload, field), clocks=network_latency) != getattr(output_node.payload, field)):
+                                        m.d.comb += match.eq(0)
+                                with m.If(match):
+                                    m.d.comb += found_input.eq(1)
+                            m.d.comb += Assert(found_input)
 
     def elaborate(self, platform):
         return self.m