diff --git a/libopenfpga/libarchopenfpga/arch/sample_arch.xml b/libopenfpga/libarchopenfpga/arch/sample_arch.xml
index b3bd3b2e3..f75f86530 100644
--- a/libopenfpga/libarchopenfpga/arch/sample_arch.xml
+++ b/libopenfpga/libarchopenfpga/arch/sample_arch.xml
@@ -262,9 +262,9 @@
   <switch_block>
     <switch name="sb_mux_L4" circuit_model_name="mux_2level_tapbuf"/>
   </switch_block>
-  <routing_segement>
-    <switch name="L4" circuit_model_name="chan_segment"/>
-  </routing_segement>
+  <routing_segment>
+    <segment name="L4" circuit_model_name="chan_segment"/>
+  </routing_segment>
   <complex_blocks>
     <pb_type name="io" idle_mode_name="inpad" physical_mode_name="io_phy"/>
     <mode name="io[io_phy]" disable_in_packing="true"/>
diff --git a/libopenfpga/libarchopenfpga/src/openfpga_arch.h b/libopenfpga/libarchopenfpga/src/openfpga_arch.h
index c433a74a7..f7f9108f0 100644
--- a/libopenfpga/libarchopenfpga/src/openfpga_arch.h
+++ b/libopenfpga/libarchopenfpga/src/openfpga_arch.h
@@ -1,6 +1,8 @@
 #ifndef OPENFPGA_ARCH_H
 #define OPENFPGA_ARCH_H
 
+#include <map>
+
 #include "circuit_library.h"
 #include "technology_library.h"
 #include "simulation_setting.h"
@@ -11,12 +13,35 @@ namespace openfpga {
 
 /* A unified data structure to store circuit-level settings,
  * including circuit library, technology library and simulation parameters
+ *
+ * Note: 
+ * Once this struct is built by function read_xml_openfpga_arch()
+ * It should be READ-ONLY! Any modification should not be applied later
+ * This is to keep everything well modularized
  */
 struct Arch {
+  /* Circuit models */
   CircuitLibrary circuit_lib;
+  
+  /* Technology devices */
   TechnologyLibrary tech_lib;
+
+  /* Simulation settings */
   SimulationSetting sim_setting;
+
+  /* Configuration protocol settings */
   ConfigProtocol config_protocol;
+
+  /* Mapping from the names of routing switches 
+   * to circuit models in circuit library 
+   */
+  std::map<std::string, CircuitModelId> cb_switch2circuit;
+  std::map<std::string, CircuitModelId> sb_switch2circuit;
+
+  /* Mapping from the names of routing segments
+   * to circuit models in circuit library 
+   */
+  std::map<std::string, CircuitModelId> routing_seg2circuit;
 };
 
 } /* namespace openfpga ends */
diff --git a/libopenfpga/libarchopenfpga/src/read_xml_openfpga_arch.cpp b/libopenfpga/libarchopenfpga/src/read_xml_openfpga_arch.cpp
index 7fac90fcd..c9cc2652b 100644
--- a/libopenfpga/libarchopenfpga/src/read_xml_openfpga_arch.cpp
+++ b/libopenfpga/libarchopenfpga/src/read_xml_openfpga_arch.cpp
@@ -17,6 +17,7 @@
 #include "read_xml_circuit_library.h"
 #include "read_xml_simulation_setting.h"
 #include "read_xml_config_protocol.h"
+#include "read_xml_routing_circuit.h"
 #include "read_xml_openfpga_arch.h"
 #include "openfpga_arch_linker.h"
 
@@ -63,6 +64,22 @@ openfpga::Arch read_xml_openfpga_arch(const char* arch_file_name) {
     /* Build the internal link between configuration protocol and circuit library */
     link_config_protocol_to_circuit_library(openfpga_arch);
 
+    /* Parse the connection block circuit definition */
+    openfpga_arch.cb_switch2circuit = read_xml_cb_switch_circuit(xml_openfpga_arch, loc_data,
+                                                                 openfpga_arch.circuit_lib);
+
+    /* Parse the connection block circuit definition */
+    openfpga_arch.cb_switch2circuit = read_xml_cb_switch_circuit(xml_openfpga_arch, loc_data,
+                                                                 openfpga_arch.circuit_lib);
+
+    /* Parse the switch block circuit definition */
+    openfpga_arch.sb_switch2circuit = read_xml_sb_switch_circuit(xml_openfpga_arch, loc_data,
+                                                                 openfpga_arch.circuit_lib);
+
+    /* Parse the routing segment circuit definition */
+    openfpga_arch.routing_seg2circuit = read_xml_routing_segment_circuit(xml_openfpga_arch, loc_data,
+                                                                         openfpga_arch.circuit_lib);
+
     /* Second node should be <openfpga_simulation_setting> */
     auto xml_simulation_settings = get_single_child(doc, "openfpga_simulation_setting", loc_data); 
 
diff --git a/libopenfpga/libarchopenfpga/src/read_xml_routing_circuit.cpp b/libopenfpga/libarchopenfpga/src/read_xml_routing_circuit.cpp
new file mode 100644
index 000000000..366a3ca4b
--- /dev/null
+++ b/libopenfpga/libarchopenfpga/src/read_xml_routing_circuit.cpp
@@ -0,0 +1,186 @@
+/********************************************************************
+ * This file includes the top-level function of this library
+ * which reads an XML modeling OpenFPGA architecture to the associated
+ * data structures
+ *******************************************************************/
+#include <string>
+
+/* Headers from pugi XML library */
+#include "pugixml.hpp"
+#include "pugixml_util.hpp"
+
+/* Headers from vtr util library */
+#include "vtr_assert.h"
+
+/* Headers from libarchfpga */
+#include "arch_error.h"
+#include "read_xml_util.h"
+
+#include "read_xml_routing_circuit.h"
+
+/********************************************************************
+ * Find the circuit model id for a routing switch as defined in XML
+ *******************************************************************/
+static 
+CircuitModelId find_routing_circuit_model(pugi::xml_node& xml_switch,
+                                          const pugiutil::loc_data& loc_data,
+                                          const CircuitLibrary& circuit_lib,
+                                          const std::string& switch_model_name,
+                                          const e_circuit_model_type& expected_circuit_model_type) {
+  /* Find the circuit model id in circuit library */
+  CircuitModelId switch_model = circuit_lib.model(switch_model_name);
+  /* Ensure we have a valid circuit model id! */
+  if (CircuitModelId::INVALID() == switch_model) {
+    archfpga_throw(loc_data.filename_c_str(), loc_data.line(xml_switch),
+                   "Invalid circuit model name '%s'! Unable to find it in circuit library\n",
+                   switch_model_name.c_str());
+  }
+  /* Check the type of switch model, it must be a specific type!!! 
+   * For CB/SB switches, the type must be a multiplexer
+   * For routing segments, the type must be a channel wire
+   * TODO: decide where to put these checking codes
+   * This can be done here or in the function check_arch()
+   */
+  if (expected_circuit_model_type != circuit_lib.model_type(switch_model)) {
+    archfpga_throw(loc_data.filename_c_str(), loc_data.line(xml_switch),
+                   "Circuit model '%s' must be a type of '%s'\n",
+                   switch_model_name.c_str(), CIRCUIT_MODEL_TYPE_STRING[expected_circuit_model_type]);
+  }
+   
+  return switch_model;
+}
+
+/********************************************************************
+ * Parse XML codes about <connection_block> to an object of name-to-circuit mapping
+ * Note: this function should be called AFTER the parsing of circuit library!!!
+ *******************************************************************/
+std::map<std::string, CircuitModelId> read_xml_cb_switch_circuit(pugi::xml_node& Node,
+                                                                 const pugiutil::loc_data& loc_data,
+                                                                 const CircuitLibrary& circuit_lib) {
+  std::map<std::string, CircuitModelId> cb_switch2circuit;
+
+  /* Parse cb switch list */
+  pugi::xml_node xml_cb_switch = get_single_child(Node, "connection_block", loc_data);
+
+  /* Iterate over the children under this node,
+   * each child should be named after switch
+   */
+  for (pugi::xml_node xml_switch : xml_cb_switch.children()) {
+    /* Error out if the XML child has an invalid name! */
+    if (xml_switch.name() != std::string("switch")) {
+      bad_tag(xml_switch, loc_data, xml_cb_switch, {"switch"});
+    }
+    /* Get the switch name */ 
+    std::string switch_name = get_attribute(xml_switch, "name", loc_data).as_string();
+
+    /* Get the switch circuit model name */ 
+    std::string switch_model_name = get_attribute(xml_switch, "circuit_model_name", loc_data).as_string();
+
+    CircuitModelId switch_model = find_routing_circuit_model(xml_switch, loc_data,
+                                                             circuit_lib, switch_model_name, 
+                                                             CIRCUIT_MODEL_MUX);
+
+    /* Ensure that there is no duplicated switch names defined here */
+    std::map<std::string, CircuitModelId>::const_iterator it = cb_switch2circuit.find(switch_name);
+    if (it != cb_switch2circuit.end()) {
+      archfpga_throw(loc_data.filename_c_str(), loc_data.line(xml_switch),
+                     "Switch name '%s' has been defined more than once!\n",
+                     switch_name.c_str());
+    }
+
+    /* Pass all the check, we can add it to the map */
+    cb_switch2circuit[switch_name] = switch_model; 
+  } 
+
+  return cb_switch2circuit;
+}
+
+/********************************************************************
+ * Parse XML codes about <switch_block> to an object of name-to-circuit mapping
+ * Note: this function should be called AFTER the parsing of circuit library!!!
+ *******************************************************************/
+std::map<std::string, CircuitModelId> read_xml_sb_switch_circuit(pugi::xml_node& Node,
+                                                                 const pugiutil::loc_data& loc_data,
+                                                                 const CircuitLibrary& circuit_lib) {
+  std::map<std::string, CircuitModelId> sb_switch2circuit;
+
+  /* Parse cb switch list */
+  pugi::xml_node xml_sb_switch = get_single_child(Node, "switch_block", loc_data);
+
+  /* Iterate over the children under this node,
+   * each child should be named after switch
+   */
+  for (pugi::xml_node xml_switch : xml_sb_switch.children()) {
+    /* Error out if the XML child has an invalid name! */
+    if (xml_switch.name() != std::string("switch")) {
+      bad_tag(xml_switch, loc_data, xml_sb_switch, {"switch"});
+    }
+    /* Get the switch name */ 
+    std::string switch_name = get_attribute(xml_switch, "name", loc_data).as_string();
+
+    /* Get the switch circuit model name */ 
+    std::string switch_model_name = get_attribute(xml_switch, "circuit_model_name", loc_data).as_string();
+
+    CircuitModelId switch_model = find_routing_circuit_model(xml_switch, loc_data,
+                                                             circuit_lib, switch_model_name,
+                                                             CIRCUIT_MODEL_MUX);
+
+    /* Ensure that there is no duplicated switch names defined here */
+    std::map<std::string, CircuitModelId>::const_iterator it = sb_switch2circuit.find(switch_name);
+    if (it != sb_switch2circuit.end()) {
+      archfpga_throw(loc_data.filename_c_str(), loc_data.line(xml_switch),
+                     "Switch name '%s' has been defined more than once!\n",
+                     switch_name.c_str());
+    }
+
+    /* Pass all the check, we can add it to the map */
+    sb_switch2circuit[switch_name] = switch_model; 
+  } 
+
+  return sb_switch2circuit;
+}
+
+/********************************************************************
+ * Parse XML codes about <routing_segment> to an object of name-to-circuit mapping
+ * Note: this function should be called AFTER the parsing of circuit library!!!
+ *******************************************************************/
+std::map<std::string, CircuitModelId> read_xml_routing_segment_circuit(pugi::xml_node& Node,
+                                                                       const pugiutil::loc_data& loc_data,
+                                                                       const CircuitLibrary& circuit_lib) {
+  std::map<std::string, CircuitModelId> seg2circuit;
+
+  /* Parse cb switch list */
+  pugi::xml_node xml_segments= get_single_child(Node, "routing_segment", loc_data);
+
+  /* Iterate over the children under this node,
+   * each child should be named after switch
+   */
+  for (pugi::xml_node xml_seg : xml_segments.children()) {
+    /* Error out if the XML child has an invalid name! */
+    if (xml_seg.name() != std::string("segment")) {
+      bad_tag(xml_seg, loc_data, xml_segments, {"segment"});
+    }
+    /* Get the switch name */ 
+    std::string seg_name = get_attribute(xml_seg, "name", loc_data).as_string();
+
+    /* Get the routing segment circuit model name */ 
+    std::string seg_model_name = get_attribute(xml_seg, "circuit_model_name", loc_data).as_string();
+
+    CircuitModelId seg_model = find_routing_circuit_model(xml_seg, loc_data,
+                                                          circuit_lib, seg_model_name,
+                                                          CIRCUIT_MODEL_CHAN_WIRE);
+  
+    /* Ensure that there is no duplicated seg names defined here */
+    std::map<std::string, CircuitModelId>::const_iterator it = seg2circuit.find(seg_name);
+    if (it != seg2circuit.end()) {
+      archfpga_throw(loc_data.filename_c_str(), loc_data.line(xml_seg),
+                     "Segment name '%s' has been defined more than once!\n",
+                     seg_name.c_str());
+    }
+
+    /* Pass all the check, we can add it to the map */
+    seg2circuit[seg_name] = seg_model; 
+  } 
+
+  return seg2circuit;
+}
diff --git a/libopenfpga/libarchopenfpga/src/read_xml_routing_circuit.h b/libopenfpga/libarchopenfpga/src/read_xml_routing_circuit.h
new file mode 100644
index 000000000..4646d7e3a
--- /dev/null
+++ b/libopenfpga/libarchopenfpga/src/read_xml_routing_circuit.h
@@ -0,0 +1,29 @@
+#ifndef READ_XML_ROUTING_CIRCUIT_H
+#define READ_XML_ROUTING_CIRCUIT_H
+
+/********************************************************************
+ * Include header files that are required by function declaration
+ *******************************************************************/
+#include <string>
+#include <map>
+
+#include "pugixml_util.hpp"
+#include "pugixml.hpp"
+#include "circuit_library.h"
+
+/********************************************************************
+ * Function declaration
+ *******************************************************************/
+std::map<std::string, CircuitModelId> read_xml_cb_switch_circuit(pugi::xml_node& Node,
+                                                                 const pugiutil::loc_data& loc_data,
+                                                                 const CircuitLibrary& circuit_lib);
+
+std::map<std::string, CircuitModelId> read_xml_sb_switch_circuit(pugi::xml_node& Node,
+                                                                 const pugiutil::loc_data& loc_data,
+                                                                 const CircuitLibrary& circuit_lib);
+
+std::map<std::string, CircuitModelId> read_xml_routing_segment_circuit(pugi::xml_node& Node,
+                                                                       const pugiutil::loc_data& loc_data,
+                                                                       const CircuitLibrary& circuit_lib);
+
+#endif
diff --git a/libopenfpga/libarchopenfpga/src/read_xml_simulation_setting.cpp b/libopenfpga/libarchopenfpga/src/read_xml_simulation_setting.cpp
index 26f40d1ac..60821e2ed 100644
--- a/libopenfpga/libarchopenfpga/src/read_xml_simulation_setting.cpp
+++ b/libopenfpga/libarchopenfpga/src/read_xml_simulation_setting.cpp
@@ -268,4 +268,3 @@ SimulationSetting read_xml_simulation_setting(pugi::xml_node& Node,
 
   return sim_setting;
 }
-
diff --git a/libopenfpga/libarchopenfpga/src/write_xml_openfpga_arch.cpp b/libopenfpga/libarchopenfpga/src/write_xml_openfpga_arch.cpp
index c5e6c7bba..444cca3cc 100644
--- a/libopenfpga/libarchopenfpga/src/write_xml_openfpga_arch.cpp
+++ b/libopenfpga/libarchopenfpga/src/write_xml_openfpga_arch.cpp
@@ -12,6 +12,7 @@
 #include "write_xml_technology_library.h"
 #include "write_xml_simulation_setting.h"
 #include "write_xml_config_protocol.h"
+#include "write_xml_routing_circuit.h"
 #include "write_xml_openfpga_arch.h"
 
 /********************************************************************
@@ -39,6 +40,15 @@ void write_xml_openfpga_arch(const char* fname,
   /* Write the configuration protocol */
   write_xml_config_protocol(fp, fname, openfpga_arch.config_protocol, openfpga_arch.circuit_lib);
 
+  /* Write the connection block circuit definition */
+  write_xml_cb_switch_circuit(fp, fname, openfpga_arch.circuit_lib, openfpga_arch.cb_switch2circuit);
+
+  /* Write the switch block circuit definition */
+  write_xml_sb_switch_circuit(fp, fname, openfpga_arch.circuit_lib, openfpga_arch.sb_switch2circuit);
+
+  /* Write the routing segment circuit definition */
+  write_xml_routing_segment_circuit(fp, fname, openfpga_arch.circuit_lib, openfpga_arch.routing_seg2circuit);
+
   fp << "</openfpga_architecture>" << "\n";
 
   /* Write the simulation */
diff --git a/libopenfpga/libarchopenfpga/src/write_xml_routing_circuit.cpp b/libopenfpga/libarchopenfpga/src/write_xml_routing_circuit.cpp
new file mode 100644
index 000000000..0d0b28446
--- /dev/null
+++ b/libopenfpga/libarchopenfpga/src/write_xml_routing_circuit.cpp
@@ -0,0 +1,99 @@
+/********************************************************************
+ * This file includes functions that outputs routing circuit definition
+ * to XML format
+ *******************************************************************/
+/* Headers from system goes first */
+#include <string>
+#include <algorithm>
+
+/* Headers from vtr util library */
+#include "vtr_assert.h"
+#include "vtr_log.h"
+#include "openfpga_digest.h"
+
+/* Headers from readarchopenfpga library */
+#include "write_xml_utils.h" 
+#include "write_xml_routing_circuit.h"
+
+/********************************************************************
+ * Write switch circuit model definition in XML format
+ *******************************************************************/
+static 
+void write_xml_routing_component_circuit(std::fstream& fp,
+                                         const char* fname,
+                                         const std::string& routing_component_name, 
+                                         const CircuitLibrary& circuit_lib,
+                                         const std::map<std::string, CircuitModelId>& switch2circuit) {
+  /* Validate the file stream */
+  openfpga::check_file_stream(fname, fp);
+
+  /* Iterate over the mapping */
+  for (std::map<std::string, CircuitModelId>::const_iterator it = switch2circuit.begin(); 
+       it != switch2circuit.end(); 
+       ++it) {
+    fp << "\t\t" << "<" << routing_component_name;
+    write_xml_attribute(fp, "name", it->first.c_str()); 
+    write_xml_attribute(fp, "circuit_model_name", circuit_lib.model_name(it->second).c_str()); 
+    fp << "/>" << "\n";
+  }
+}
+
+/********************************************************************
+ * Write Connection block circuit models in XML format
+ *******************************************************************/
+void write_xml_cb_switch_circuit(std::fstream& fp,
+                                 const char* fname,
+                                 const CircuitLibrary& circuit_lib,
+                                 const std::map<std::string, CircuitModelId>& switch2circuit) {
+  /* Validate the file stream */
+  openfpga::check_file_stream(fname, fp);
+  
+  /* Write the root node */
+  fp << "\t" << "<connection_block>" << "\n";
+
+  /* Write each switch circuit definition */ 
+  write_xml_routing_component_circuit(fp, fname, std::string("switch"), circuit_lib, switch2circuit);
+
+  /* Finish writing the root node */
+  fp << "\t" << "</connection_block>" << "\n";
+}
+
+/********************************************************************
+ * Write Switch block circuit models in XML format
+ *******************************************************************/
+void write_xml_sb_switch_circuit(std::fstream& fp,
+                                 const char* fname,
+                                 const CircuitLibrary& circuit_lib,
+                                 const std::map<std::string, CircuitModelId>& switch2circuit) {
+  /* Validate the file stream */
+  openfpga::check_file_stream(fname, fp);
+  
+  /* Write the root node */
+  fp << "\t" << "<switch_block>" << "\n";
+
+  /* Write each switch circuit definition */ 
+  write_xml_routing_component_circuit(fp, fname, std::string("switch"), circuit_lib, switch2circuit);
+
+  /* Finish writing the root node */
+  fp << "\t" << "</switch_block>" << "\n";
+}
+
+/********************************************************************
+ * Write routing segment circuit models in XML format
+ *******************************************************************/
+void write_xml_routing_segment_circuit(std::fstream& fp,
+                                       const char* fname,
+                                       const CircuitLibrary& circuit_lib,
+                                       const std::map<std::string, CircuitModelId>& seg2circuit) {
+  /* Validate the file stream */
+  openfpga::check_file_stream(fname, fp);
+  
+  /* Write the root node */
+  fp << "\t" << "<routing_segment>" << "\n";
+
+  /* Write each routing segment circuit definition */ 
+  write_xml_routing_component_circuit(fp, fname, std::string("segment"), circuit_lib, seg2circuit);
+
+  /* Finish writing the root node */
+  fp << "\t" << "</routing_segment>" << "\n";
+}
diff --git a/libopenfpga/libarchopenfpga/src/write_xml_routing_circuit.h b/libopenfpga/libarchopenfpga/src/write_xml_routing_circuit.h
new file mode 100644
index 000000000..75f4890ee
--- /dev/null
+++ b/libopenfpga/libarchopenfpga/src/write_xml_routing_circuit.h
@@ -0,0 +1,31 @@
+#ifndef WRITE_XML_ROUTING_CIRCUIT_H
+#define WRITE_XML_ROUTING_CIRCUIT_H
+
+/********************************************************************
+ * Include header files that are required by function declaration
+ *******************************************************************/
+#include <fstream>
+#include <map>
+#include <string>
+
+#include "circuit_library.h"
+
+/********************************************************************
+ * Function declaration
+ *******************************************************************/
+void write_xml_cb_switch_circuit(std::fstream& fp,
+                                 const char* fname,
+                                 const CircuitLibrary& circuit_lib,
+                                 const std::map<std::string, CircuitModelId>& switch2circuit);
+
+void write_xml_sb_switch_circuit(std::fstream& fp,
+                                 const char* fname,
+                                 const CircuitLibrary& circuit_lib,
+                                 const std::map<std::string, CircuitModelId>& switch2circuit);
+
+void write_xml_routing_segment_circuit(std::fstream& fp,
+                                       const char* fname,
+                                       const CircuitLibrary& circuit_lib,
+                                       const std::map<std::string, CircuitModelId>& seg2circuit);
+
+#endif