diff --git a/rtc_base/socket_address_pair.cc b/rtc_base/socket_address_pair.cc
index 54f70ff..351dbd3 100644
--- a/rtc_base/socket_address_pair.cc
+++ b/rtc_base/socket_address_pair.cc
@@ -10,10 +10,10 @@
 
 #include "rtc_base/socket_address_pair.h"
 
-namespace rtc {
+namespace webrtc {
 
-SocketAddressPair::SocketAddressPair(const SocketAddress& src,
-                                     const SocketAddress& dest)
+SocketAddressPair::SocketAddressPair(const rtc::SocketAddress& src,
+                                     const rtc::SocketAddress& dest)
     : src_(src), dest_(dest) {}
 
 bool SocketAddressPair::operator==(const SocketAddressPair& p) const {
@@ -36,4 +36,4 @@
   return src_.Hash() ^ dest_.Hash();
 }
 
-}  // namespace rtc
+}  // namespace webrtc
diff --git a/rtc_base/socket_address_pair.h b/rtc_base/socket_address_pair.h
index f315e64..aa1b01c 100644
--- a/rtc_base/socket_address_pair.h
+++ b/rtc_base/socket_address_pair.h
@@ -15,7 +15,7 @@
 
 #include "rtc_base/socket_address.h"
 
-namespace rtc {
+namespace webrtc {
 
 // Records a pair (source,destination) of socket addresses.  The two addresses
 // identify a connection between two machines.  (For UDP, this "connection" is
@@ -23,10 +23,11 @@
 class SocketAddressPair {
  public:
   SocketAddressPair() {}
-  SocketAddressPair(const SocketAddress& srs, const SocketAddress& dest);
+  SocketAddressPair(const rtc::SocketAddress& srs,
+                    const rtc::SocketAddress& dest);
 
-  const SocketAddress& source() const { return src_; }
-  const SocketAddress& destination() const { return dest_; }
+  const rtc::SocketAddress& source() const { return src_; }
+  const rtc::SocketAddress& destination() const { return dest_; }
 
   bool operator==(const SocketAddressPair& r) const;
   bool operator<(const SocketAddressPair& r) const;
@@ -34,10 +35,16 @@
   size_t Hash() const;
 
  private:
-  SocketAddress src_;
-  SocketAddress dest_;
+  rtc::SocketAddress src_;
+  rtc::SocketAddress dest_;
 };
 
+}  //  namespace webrtc
+
+// Re-export symbols from the webrtc namespace for backwards compatibility.
+// TODO(bugs.webrtc.org/4222596): Remove once all references are updated.
+namespace rtc {
+using ::webrtc::SocketAddressPair;
 }  // namespace rtc
 
 #endif  // RTC_BASE_SOCKET_ADDRESS_PAIR_H_
diff --git a/rtc_base/virtual_socket_server.cc b/rtc_base/virtual_socket_server.cc
index 51a9901..de4e181 100644
--- a/rtc_base/virtual_socket_server.cc
+++ b/rtc_base/virtual_socket_server.cc
@@ -869,8 +869,8 @@
   // multiple clients to connect to the same server address.
   SocketAddress local_normalized(local.ipaddr().Normalized(), local.port());
   SocketAddress remote_normalized(remote.ipaddr().Normalized(), remote.port());
-  SocketAddressPair address_pair(local_normalized, remote_normalized);
-  connections_->insert(std::pair<SocketAddressPair, VirtualSocket*>(
+  webrtc::SocketAddressPair address_pair(local_normalized, remote_normalized);
+  connections_->insert(std::pair<webrtc::SocketAddressPair, VirtualSocket*>(
       address_pair, remote_socket));
 }
 
@@ -879,7 +879,7 @@
     const SocketAddress& remote) {
   SocketAddress local_normalized(local.ipaddr().Normalized(), local.port());
   SocketAddress remote_normalized(remote.ipaddr().Normalized(), remote.port());
-  SocketAddressPair address_pair(local_normalized, remote_normalized);
+  webrtc::SocketAddressPair address_pair(local_normalized, remote_normalized);
   ConnectionMap::iterator it = connections_->find(address_pair);
   return (connections_->end() != it) ? it->second : nullptr;
 }
@@ -888,7 +888,7 @@
                                            const SocketAddress& remote) {
   SocketAddress local_normalized(local.ipaddr().Normalized(), local.port());
   SocketAddress remote_normalized(remote.ipaddr().Normalized(), remote.port());
-  SocketAddressPair address_pair(local_normalized, remote_normalized);
+  webrtc::SocketAddressPair address_pair(local_normalized, remote_normalized);
   connections_->erase(address_pair);
 }
 
diff --git a/rtc_base/virtual_socket_server.h b/rtc_base/virtual_socket_server.h
index d462288..6de8dc0 100644
--- a/rtc_base/virtual_socket_server.h
+++ b/rtc_base/virtual_socket_server.h
@@ -23,6 +23,7 @@
 #include "rtc_base/checks.h"
 #include "rtc_base/event.h"
 #include "rtc_base/fake_clock.h"
+#include "rtc_base/socket_address_pair.h"
 #include "rtc_base/socket_server.h"
 #include "rtc_base/synchronization/mutex.h"
 
@@ -30,7 +31,6 @@
 
 class VirtualSocketPacket;
 class VirtualSocketServer;
-class SocketAddressPair;
 
 // Implements the socket interface using the virtual network. Packets are
 // passed in tasks using the thread of the socket server.
@@ -434,7 +434,7 @@
   static bool CanInteractWith(VirtualSocket* local, VirtualSocket* remote);
 
   typedef std::map<SocketAddress, VirtualSocket*> AddressMap;
-  typedef std::map<SocketAddressPair, VirtualSocket*> ConnectionMap;
+  typedef std::map<webrtc::SocketAddressPair, VirtualSocket*> ConnectionMap;
 
   // May be null if the test doesn't use a fake clock, or it does but doesn't
   // use ProcessMessagesUntilIdle.