diff --git a/src/Engine/Network/NetworkManager.cpp b/src/Engine/Network/NetworkManager.cpp
index 015228f..7ecca8c 100644
--- a/src/Engine/Network/NetworkManager.cpp
+++ b/src/Engine/Network/NetworkManager.cpp
@@ -23,5 +23,21 @@ enzo::nt::NetworkManager* enzo::nt::NetworkManager::getInstance()
     return instancePtr_;
 }
 
+enzo::nt::GeometryOperator& enzo::nt::NetworkManager::getGeoOperator(nt::OpId opId)
+{
+    return *gopStore_.at(opId);
+}
+
+bool enzo::nt::NetworkManager::isValidOp(nt::OpId opId)
+{
+    auto it = gopStore_.find(opId);
+    if( it == gopStore_.end() || it->second==nullptr )
+    {
+        return false;
+    }
+    return true;
+}
+
+
 enzo::nt::NetworkManager* enzo::nt::NetworkManager::instancePtr_ = nullptr;
 
diff --git a/src/Engine/Network/NetworkManager.h b/src/Engine/Network/NetworkManager.h
index 3f9ed77..4d95b8c 100644
--- a/src/Engine/Network/NetworkManager.h
+++ b/src/Engine/Network/NetworkManager.h
@@ -14,6 +14,9 @@ public:
 
     static NetworkManager* getInstance();
 
+    bool isValidOp(nt::OpId opId);
+    GeometryOperator& getGeoOperator(nt::OpId opId);
+
 private:
     static NetworkManager* instancePtr_;
     NetworkManager() {};
diff --git a/src/Engine/Operator/GeometryOperator.cpp b/src/Engine/Operator/GeometryOperator.cpp
index 5d2a7bc..5d570d4 100644
--- a/src/Engine/Operator/GeometryOperator.cpp
+++ b/src/Engine/Operator/GeometryOperator.cpp
@@ -1,9 +1,55 @@
 #include "Engine/Operator/GeometryOperator.h"
-#include <cstdint>
+#include <optional>
 
 using namespace enzo;
 
 nt::GeometryOperator::GeometryOperator()
 {
+    // TODO: drive by geometry definition
+    maxInputs_=4;
+    maxOutputs_=4;
+
+    inputIds_ = std::vector<std::optional<nt::OpId>>(maxInputs_, std::nullopt);
+    outputIds_ = std::vector<std::optional<nt::OpId>>(maxOutputs_, std::nullopt);
 }
 
+bool nt::GeometryOperator::setInput(unsigned int inputNumber, nt::OpId opId)
+{
+    if(inputNumber>=maxInputs_)
+    {
+        return false;
+    }
+    inputIds_[inputNumber] = opId;
+
+    return true;
+}
+bool nt::GeometryOperator::setOutput(unsigned int outputNumber, nt::OpId opId)
+{
+
+    if(outputNumber>=maxOutputs_)
+    {
+        return false;
+    }
+    inputIds_[outputNumber] = opId;
+    return true;
+}
+
+std::optional<nt::OpId> nt::GeometryOperator::getInput(unsigned int inputNumber) const
+{
+    if(inputNumber>=maxInputs_)
+    {
+        return std::nullopt;
+    }
+    return inputIds_.at(inputNumber);    
+}
+
+std::optional<nt::OpId> nt::GeometryOperator::getOutput(unsigned int outputNumber) const
+{
+    if(outputNumber>=maxOutputs_)
+    {
+        return std::nullopt;
+    }
+    return outputIds_.at(outputNumber);    
+}
+
+
diff --git a/src/Engine/Operator/GeometryOperator.h b/src/Engine/Operator/GeometryOperator.h
index f12013a..9160ead 100644
--- a/src/Engine/Operator/GeometryOperator.h
+++ b/src/Engine/Operator/GeometryOperator.h
@@ -1,5 +1,6 @@
 #pragma once
 #include "Engine/Types.h"
+#include <optional>
 
 namespace enzo::nt {
 
@@ -7,9 +8,16 @@ class GeometryOperator
 {
 public:
     GeometryOperator();
-    // nodeDef
+    bool setInput(unsigned int inputNumber, nt::OpId opId);
+    bool setOutput(unsigned int outputNumber, nt::OpId opId);
+    std::optional<nt::OpId> getInput(unsigned int inputNumber) const;
+    std::optional<nt::OpId> getOutput(unsigned int outputNumber) const;
 
 private:
+    std::vector<std::optional<nt::OpId>> inputIds_;
+    std::vector<std::optional<nt::OpId>> outputIds_;
+    unsigned int maxInputs_;
+    unsigned int maxOutputs_;
 
 };
 }
diff --git a/tests/NetworkTests.cpp b/tests/NetworkTests.cpp
index bff0ab2..db32dac 100644
--- a/tests/NetworkTests.cpp
+++ b/tests/NetworkTests.cpp
@@ -1,11 +1,25 @@
 #include <catch2/catch_test_macros.hpp>
 #include "Engine/Network/NetworkManager.h"
+#include "Engine/Operator/GeometryOperator.h"
+#include "Engine/Types.h"
 
 
 TEST_CASE("network")
 {
     using namespace enzo;
     nt::NetworkManager* nm = nt::NetworkManager::getInstance();
-    nm->addOperator();
+    nt::OpId newOpId = nm->addOperator();
+    nt::OpId newOpId2 = nm->addOperator();
+
+    REQUIRE(nm->isValidOp(newOpId));
+    if(nm->isValidOp(newOpId))
+    {
+        nt::GeometryOperator& newOp = nm->getGeoOperator(newOpId); 
+        REQUIRE(newOp.setInput(0, newOpId2));
+
+        std::optional<nt::OpId> returnOpId = newOp.getInput(0);
+        REQUIRE(returnOpId.has_value());
+        REQUIRE(*returnOpId==newOpId2);
+    }
 }