diff --git a/aether/channels/ethernet_transport_factory.cpp b/aether/channels/ethernet_transport_factory.cpp
index 4c376576..b37adc8a 100644
--- a/aether/channels/ethernet_transport_factory.cpp
+++ b/aether/channels/ethernet_transport_factory.cpp
@@ -36,6 +36,11 @@
 // IWYU pragma: end_keeps
 
 namespace ae {
+namespace ethernet_transport_factory_internal {
+static constexpr auto kTcpPacketQueueCapacity = AE_TCP_PACKET_QUEUE_SIZE;
+static constexpr auto kUdpPacketQueueCapacity = AE_UDP_PACKET_QUEUE_SIZE;
+}  // namespace ethernet_transport_factory_internal
+
 std::unique_ptr<ByteIStream> EthernetTransportFactory::Create(
     AeContext const& ae_context, Ptr<IPoller> const& poller,
     Endpoint address_port_protocol) {
@@ -70,8 +75,10 @@ std::unique_ptr<ByteIStream> EthernetTransportFactory::BuildTcp(
   using SocketType = WinTcpSocket;
 #    endif
 
-  return std::make_unique<TcpTransport<SocketType, AE_TCP_PACKET_QUEUE_SIZE>>(
-      ae_context, poller, std::move(address_port_protocol));
+  using Transport = TcpTransport<
+      SocketType, ethernet_transport_factory_internal::kTcpPacketQueueCapacity>;
+  return std::make_unique<Transport>(ae_context, poller,
+                                     std::move(address_port_protocol));
 #  else
   static_assert(false, "No transport enabled");
 #  endif
@@ -100,8 +107,10 @@ std::unique_ptr<ByteIStream> EthernetTransportFactory::BuildUdp(
 #    elif WIN_SOCKET_ENABLED
   using SocketType = WinUdpSocket;
 #    endif
-  return std::make_unique<UdpTransport<SocketType, AE_UDP_PACKET_QUEUE_SIZE>>(
-      ae_context, poller, std::move(address_port_protocol));
+  using Transport = UdpTransport<
+      SocketType, ethernet_transport_factory_internal::kUdpPacketQueueCapacity>;
+  return std::make_unique<Transport>(ae_context, poller,
+                                     std::move(address_port_protocol));
 #  else
   static_assert(false, "No transport enabled");
 #  endif
diff --git a/aether/client_messages/p2p_message_stream.h b/aether/client_messages/p2p_message_stream.h
index 8fdb5eaa..600bb5a2 100644
--- a/aether/client_messages/p2p_message_stream.h
+++ b/aether/client_messages/p2p_message_stream.h
@@ -21,6 +21,7 @@
 #include <optional>
 
 #include "aether/common.h"
+#include "aether/config.h"
 
 #include "aether-objects/ptr/ptr_view.h"
 #include "aether/ae_context.h"
@@ -60,6 +61,9 @@ class P2pStream final : public ByteIStream {
   Uid const& destination() const;
 
  private:
+  static constexpr auto kBufferCapacity = AE_P2P_MESSAGE_STREAM_BUFFER_CAPACITY;
+  using Buffer = BufferWrite<AeMessage, kBufferCapacity>;
+
   void ConnectReceive();
   void ConnectSend();
 
@@ -76,7 +80,7 @@ class P2pStream final : public ByteIStream {
 
   // connection to destination cloud
   std::unique_ptr<CloudServerConnections> dest_cloud_conn_;
-  BufferWrite<AeMessage, 100> buffer_write_;
+  Buffer buffer_write_;
   std::unique_ptr<p2p_stream_internal::MessageSendStream> message_send_stream_;
 
   OutDataEvent out_data_event_;
diff --git a/aether/client_messages/p2p_safe_message_stream.h b/aether/client_messages/p2p_safe_message_stream.h
index bad726d2..e32a16ce 100644
--- a/aether/client_messages/p2p_safe_message_stream.h
+++ b/aether/client_messages/p2p_safe_message_stream.h
@@ -17,23 +17,24 @@
 #ifndef AETHER_CLIENT_MESSAGES_P2P_SAFE_MESSAGE_STREAM_H_
 #define AETHER_CLIENT_MESSAGES_P2P_SAFE_MESSAGE_STREAM_H_
 
-#include "aether/common.h"
 #include "aether/ae_context.h"
-#include "aether/memory.h"
+#include "aether/common.h"
 #include "aether/config.h"
-#include "aether/actions/action_context.h"
+#include "aether/memory.h"
 
+#include "aether/safe_stream/safe_stream_config.h"
 #include "aether/stream_api/istream.h"
 #include "aether/stream_api/sized_packet_gate.h"
-#include "aether/safe_stream/safe_stream_config.h"
 
 namespace ae {
 template <std::size_t Capacity>
 class SafeStream;
 
+static constexpr inline std::size_t kP2pSafeStreamCapacity =
+    AE_SAFE_STREAM_CAPACITY;
 class P2pSafeStream final : public ByteIStream {
  public:
-  using SafeStreamImpl = SafeStream<AE_SAFE_STREAM_CAPACITY>;
+  using SafeStreamImpl = SafeStream<kP2pSafeStreamCapacity>;
 
   P2pSafeStream(AeContext const& ae_context, SafeStreamConfig const& config,
                 std::shared_ptr<ByteIStream> p2p_stream);
@@ -49,7 +50,6 @@ class P2pSafeStream final : public ByteIStream {
 
  private:
   SizedPacketGate sized_packet_gate_;
-  // TODO: add config
   std::unique_ptr<SafeStreamImpl> safe_stream_;
   std::shared_ptr<ByteIStream> p2p_stream_;
   OutDataEvent out_data_event_;
diff --git a/aether/config.h b/aether/config.h
index f9ef0d3c..543cd7da 100644
--- a/aether/config.h
+++ b/aether/config.h
@@ -17,6 +17,10 @@
 #ifndef AETHER_CONFIG_H_
 #define AETHER_CONFIG_H_
 
+// Defines Aether's compile-time configuration defaults. USER_CONFIG, when
+// defined, is included before these defaults so it can override them. Add new
+// options to aether/tele_compile_options.h for telemetry reporting.
+
 // IWYU pragma: begin_exports
 #include <cstddef>
 #include <cstdint>
@@ -87,6 +91,51 @@
 #  define AE_TCP_PACKET_QUEUE_SIZE 100
 #endif  // AE_TCP_PACKET_QUEUE_SIZE
 
+// Buffered server connection write buffer entry count.
+#ifndef AE_SERVER_CONNECTION_BUFFER_CAPACITY
+#  define AE_SERVER_CONNECTION_BUFFER_CAPACITY 10
+#endif
+
+// Root registration server selection stream write buffer entry count.
+#ifndef AE_ROOT_REG_SERVER_BUFFER_CAPACITY
+#  define AE_ROOT_REG_SERVER_BUFFER_CAPACITY 2
+#endif
+
+// Peer-to-peer message stream write buffer entry count.
+#ifndef AE_P2P_MESSAGE_STREAM_BUFFER_CAPACITY
+#  define AE_P2P_MESSAGE_STREAM_BUFFER_CAPACITY 10
+#endif
+
+// Cloud retrieval action pool entry count.
+#ifndef AE_CLOUD_GET_CLOUD_ACTION_POOL_CAPACITY
+#  define AE_CLOUD_GET_CLOUD_ACTION_POOL_CAPACITY 5
+#endif
+
+// Cloud server retrieval action pool entry count.
+#ifndef AE_CLOUD_GET_SERVERS_ACTION_POOL_CAPACITY
+#  define AE_CLOUD_GET_SERVERS_ACTION_POOL_CAPACITY 5
+#endif
+
+// Modem network operation action pool entry count.
+#ifndef AE_MODEM_NETWORK_OP_ACTION_POOL_CAPACITY
+#  define AE_MODEM_NETWORK_OP_ACTION_POOL_CAPACITY 10
+#endif
+
+// Modem write action pool entry count.
+#ifndef AE_MODEM_WRITE_ACTION_POOL_CAPACITY
+#  define AE_MODEM_WRITE_ACTION_POOL_CAPACITY 10
+#endif
+
+// Modem TCP packet queue entry count.
+#ifndef AE_MODEM_TCP_PACKET_QUEUE_SIZE
+#  define AE_MODEM_TCP_PACKET_QUEUE_SIZE 10
+#endif
+
+// Modem UDP packet queue entry count.
+#ifndef AE_MODEM_UDP_PACKET_QUEUE_SIZE
+#  define AE_MODEM_UDP_PACKET_QUEUE_SIZE 10
+#endif
+
 #ifndef AE_SUPPORT_WEBSOCKET
 #  define AE_SUPPORT_WEBSOCKET 1
 #endif  // AE_SUPPORT_WEBSOCKET
diff --git a/aether/connection_manager/client_cloud_manager.h b/aether/connection_manager/client_cloud_manager.h
index e1755032..2cb41288 100644
--- a/aether/connection_manager/client_cloud_manager.h
+++ b/aether/connection_manager/client_cloud_manager.h
@@ -20,6 +20,8 @@
 #include <map>
 #include <optional>
 
+#include "aether/config.h"
+
 #include "aether-objects/obj/obj.h"
 #include "aether-objects/ptr/ptr.h"
 #include "aether/actions/action_pool.h"
@@ -72,6 +74,11 @@ class ClientCloudManager : public Obj {
   ClientCloudManager() = default;
 
  public:
+  static constexpr auto kGetCloudActionPoolCapacity =
+      AE_CLOUD_GET_CLOUD_ACTION_POOL_CAPACITY;
+  static constexpr auto kGetServersActionPoolCapacity =
+      AE_CLOUD_GET_SERVERS_ACTION_POOL_CAPACITY;
+
   using CloudUpdateEvent =
       Event<void(Uid const& uid, Result<Cloud::ptr const&, int>)>;
 
@@ -79,8 +86,9 @@ class ClientCloudManager : public Obj {
       ActionPool<AeContext,
                  std::variant<client_cloud_manager_internal::GetCloudFromCache,
                               GetCloudFromAether>,
-                 5>;
-  using GetServersPool = ActionPool<AeContext, GetServersAction, 5>;
+                 kGetCloudActionPoolCapacity>;
+  using GetServersPool =
+      ActionPool<AeContext, GetServersAction, kGetServersActionPoolCapacity>;
 
   explicit ClientCloudManager(ObjProp prop, ObjPtr<Aether> aether,
                               ObjPtr<Client> client);
diff --git a/aether/modems/bg95_at_modem.h b/aether/modems/bg95_at_modem.h
index 801d1379..731f8702 100644
--- a/aether/modems/bg95_at_modem.h
+++ b/aether/modems/bg95_at_modem.h
@@ -19,16 +19,16 @@
 
 #include "aether/config.h"
 #if AE_SUPPORT_MODEMS && AE_ENABLE_BG95
-#  include <set>
 #  include <memory>
+#  include <set>
 
-#  include "aether/ae_context.h"
-#  include "aether/poller/poller.h"
 #  include "aether/actions/action_pool.h"
 #  include "aether/actions/actions_queue.h"
 #  include "aether/actions/repeatable_task.h"
-#  include "aether/serial_ports/iserial_port.h"
+#  include "aether/ae_context.h"
+#  include "aether/poller/poller.h"
 #  include "aether/serial_ports/at_support/at_support.h"
+#  include "aether/serial_ports/iserial_port.h"
 
 #  include "aether/modems/imodem_driver.h"
 
@@ -95,8 +95,7 @@ class ModemStartedAlreadyOperation final : public ModemOperation {
 
 class ModemStartOperation final : public ModemOperation {
  public:
-  explicit ModemStartOperation(AeContext const& ae_context,
-                               Bg95AtModem& self);
+  explicit ModemStartOperation(AeContext const& ae_context, Bg95AtModem& self);
 
  private:
   auto SetBaudRate(kBaudRate const rate);
@@ -125,8 +124,7 @@ class ModemStoppedAlreadyOperation final : public ModemOperation {
 
 class ModemStopOperation final : public ModemOperation {
  public:
-  explicit ModemStopOperation(AeContext const& ae_context,
-                               Bg95AtModem& self);
+  explicit ModemStopOperation(AeContext const& ae_context, Bg95AtModem& self);
 
  private:
   auto Pipeline();
@@ -141,8 +139,8 @@ class ModemStopOperation final : public ModemOperation {
 class ModemSetPowerSaveParamOperation final : public ModemOperation {
  public:
   explicit ModemSetPowerSaveParamOperation(AeContext const& /*ae_context*/,
-                                            Bg95AtModem& /*self*/,
-                                            ModemPowerSaveParam /*psp*/) {
+                                           Bg95AtModem& /*self*/,
+                                           ModemPowerSaveParam /*psp*/) {
     SetResult(Ok{kIgnore});
   }
 };
@@ -150,7 +148,7 @@ class ModemSetPowerSaveParamOperation final : public ModemOperation {
 class ModemPowerOffOperation final : public ModemOperation {
  public:
   explicit ModemPowerOffOperation(AeContext const& ae_context,
-                                   Bg95AtModem& self);
+                                  Bg95AtModem& self);
 
  private:
   auto Pipeline();
@@ -174,13 +172,13 @@ class Bg95AtModem final : public IModemDriver {
   static constexpr std::uint16_t kModemMTU{1520};
 
  public:
-  explicit Bg95AtModem(AeContext const& ae_context,
-                       IPoller::ptr const& poller, ModemInit modem_init);
+  explicit Bg95AtModem(AeContext const& ae_context, IPoller::ptr const& poller,
+                       ModemInit modem_init);
 
   ModemOperation* Start() override;
   ModemOperation* Stop() override;
   OpenNetworkOperation* OpenNetwork(Protocol protocol, std::string const& host,
-                                     std::uint16_t port) override;
+                                    std::uint16_t port) override;
   ModemOperation* CloseNetwork(ConnectionIndex connect_index) override;
   WriteOperation* WritePacket(ConnectionIndex connect_index,
                               std::span<std::uint8_t const> data) override;
@@ -190,6 +188,21 @@ class Bg95AtModem final : public IModemDriver {
   ModemOperation* PowerOff() override;
 
  private:
+  static constexpr auto kNetworkOpActionPoolCapacity =
+      AE_MODEM_NETWORK_OP_ACTION_POOL_CAPACITY;
+  static constexpr auto kWriteActionPoolCapacity =
+      AE_MODEM_WRITE_ACTION_POOL_CAPACITY;
+
+  using OpenNetworkActionPool =
+      ActionPool<AeContext, bg95_modem_internal::OpenNetworkOperationImpl,
+                 kNetworkOpActionPoolCapacity>;
+  using CloseNetworkActionPool =
+      ActionPool<AeContext, bg95_modem_internal::CloseNetworkOperationImpl,
+                 kNetworkOpActionPoolCapacity>;
+  using WriteActionPool =
+      ActionPool<AeContext, bg95_modem_internal::WriteOperationImpl,
+                 kWriteActionPoolCapacity>;
+
   void Init();
   void SetupPoll();
   void PollEvent(std::int32_t handle);
@@ -208,12 +221,9 @@ class Bg95AtModem final : public IModemDriver {
   std::unique_ptr<ModemOperation> modem_stop_operation_;
   std::unique_ptr<ModemOperation> modem_set_psp_operation_;
   std::unique_ptr<ModemOperation> modem_poweroff_operation_;
-  ActionPool<AeContext, bg95_modem_internal::OpenNetworkOperationImpl, 10>
-      open_network_pool_;
-  ActionPool<AeContext, bg95_modem_internal::CloseNetworkOperationImpl, 10>
-      close_network_pool_;
-  ActionPool<AeContext, bg95_modem_internal::WriteOperationImpl, 10>
-      write_pool_;
+  OpenNetworkActionPool open_network_pool_;
+  CloseNetworkActionPool close_network_pool_;
+  WriteActionPool write_pool_;
 
   bool initiated_;
   bool started_;
@@ -222,4 +232,4 @@ class Bg95AtModem final : public IModemDriver {
 
 } /* namespace ae */
 #endif
-#endif  // AETHER_MODEMS_BG95_AT_MODEM_H_
\ No newline at end of file
+#endif  // AETHER_MODEMS_BG95_AT_MODEM_H_
diff --git a/aether/modems/sim7070_at_modem.h b/aether/modems/sim7070_at_modem.h
index 58707c01..82ebbfeb 100644
--- a/aether/modems/sim7070_at_modem.h
+++ b/aether/modems/sim7070_at_modem.h
@@ -20,16 +20,16 @@
 #include "aether/config.h"
 
 #if AE_SUPPORT_MODEMS && AE_ENABLE_SIM7070
-#  include <set>
 #  include <memory>
+#  include <set>
 
-#  include "aether/ae_context.h"
-#  include "aether/poller/poller.h"
 #  include "aether/actions/action_pool.h"
 #  include "aether/actions/actions_queue.h"
 #  include "aether/actions/repeatable_task.h"
-#  include "aether/serial_ports/iserial_port.h"
+#  include "aether/ae_context.h"
+#  include "aether/poller/poller.h"
 #  include "aether/serial_ports/at_support/at_support.h"
+#  include "aether/serial_ports/iserial_port.h"
 
 #  include "aether/modems/imodem_driver.h"
 
@@ -196,6 +196,21 @@ class Sim7070AtModem final : public IModemDriver {
   ModemOperation* PowerOff() override;
 
  private:
+  static constexpr auto kNetworkOpActionPoolCapacity =
+      AE_MODEM_NETWORK_OP_ACTION_POOL_CAPACITY;
+  static constexpr auto kWriteActionPoolCapacity =
+      AE_MODEM_WRITE_ACTION_POOL_CAPACITY;
+
+  using OpenNetworkActionPool =
+      ActionPool<AeContext, sim7070_modem_internal::OpenNetworkOperationImpl,
+                 kNetworkOpActionPoolCapacity>;
+  using CloseNetworkActionPool =
+      ActionPool<AeContext, sim7070_modem_internal::CloseNetworkOperationImpl,
+                 kNetworkOpActionPoolCapacity>;
+  using WriteActionPool =
+      ActionPool<AeContext, sim7070_modem_internal::WriteOperationImpl,
+                 kWriteActionPoolCapacity>;
+
   void Init();
   void SetupPoll();
   void PollEvent(std::int32_t handle);
@@ -214,12 +229,9 @@ class Sim7070AtModem final : public IModemDriver {
   std::unique_ptr<ModemOperation> modem_stop_operation_;
   std::unique_ptr<ModemOperation> modem_set_psp_operation_;
   std::unique_ptr<ModemOperation> modem_poweroff_operation_;
-  ActionPool<AeContext, sim7070_modem_internal::OpenNetworkOperationImpl, 10>
-      open_network_pool_;
-  ActionPool<AeContext, sim7070_modem_internal::CloseNetworkOperationImpl, 10>
-      close_network_pool_;
-  ActionPool<AeContext, sim7070_modem_internal::WriteOperationImpl, 10>
-      write_pool_;
+  OpenNetworkActionPool open_network_pool_;
+  CloseNetworkActionPool close_network_pool_;
+  WriteActionPool write_pool_;
 
   bool initiated_;
   bool started_;
diff --git a/aether/modems/thingy91x_at_modem.h b/aether/modems/thingy91x_at_modem.h
index 433af8c8..46648c68 100644
--- a/aether/modems/thingy91x_at_modem.h
+++ b/aether/modems/thingy91x_at_modem.h
@@ -19,16 +19,16 @@
 
 #include "aether/config.h"
 #if AE_SUPPORT_MODEMS && AE_ENABLE_THINGY91X
-#  include <set>
 #  include <memory>
+#  include <set>
 
-#  include "aether/ae_context.h"
-#  include "aether/poller/poller.h"
 #  include "aether/actions/action_pool.h"
 #  include "aether/actions/actions_queue.h"
 #  include "aether/actions/repeatable_task.h"
-#  include "aether/serial_ports/iserial_port.h"
+#  include "aether/ae_context.h"
+#  include "aether/poller/poller.h"
 #  include "aether/serial_ports/at_support/at_support.h"
+#  include "aether/serial_ports/iserial_port.h"
 
 #  include "aether/modems/imodem_driver.h"
 
@@ -123,6 +123,21 @@ class Thingy91xAtModem final : public IModemDriver {
   ModemOperation* PowerOff() override;
 
  private:
+  static constexpr auto kNetworkOpActionPoolCapacity =
+      AE_MODEM_NETWORK_OP_ACTION_POOL_CAPACITY;
+  static constexpr auto kWriteActionPoolCapacity =
+      AE_MODEM_WRITE_ACTION_POOL_CAPACITY;
+
+  using OpenNetworkActionPool =
+      ActionPool<AeContext, thingy91x_modem_internal::OpenNetworkOperationImpl,
+                 kNetworkOpActionPoolCapacity>;
+  using CloseNetworkActionPool =
+      ActionPool<AeContext, thingy91x_modem_internal::CloseNetworkOperationImpl,
+                 kNetworkOpActionPoolCapacity>;
+  using WriteActionPool =
+      ActionPool<AeContext, thingy91x_modem_internal::WriteOperationImpl,
+                 kWriteActionPoolCapacity>;
+
   void Init();
   void SetupPoll();
   void PollEvent(std::int32_t handle, std::string_view flags);
@@ -137,12 +152,9 @@ class Thingy91xAtModem final : public IModemDriver {
   std::unique_ptr<ModemOperation> modem_stop_operation_;
   std::unique_ptr<ModemOperation> modem_set_psp_operation_;
   std::unique_ptr<ModemOperation> modem_poweroff_operation_;
-  ActionPool<AeContext, thingy91x_modem_internal::OpenNetworkOperationImpl, 10>
-      open_network_pool_;
-  ActionPool<AeContext, thingy91x_modem_internal::CloseNetworkOperationImpl, 10>
-      close_network_pool_;
-  ActionPool<AeContext, thingy91x_modem_internal::WriteOperationImpl, 10>
-      write_pool_;
+  OpenNetworkActionPool open_network_pool_;
+  CloseNetworkActionPool close_network_pool_;
+  WriteActionPool write_pool_;
 
   std::set<ConnectionIndex> connections_;
   DataEvent data_event_;
diff --git a/aether/registration/root_server_select_stream.h b/aether/registration/root_server_select_stream.h
index 6069e254..ad7a0bb6 100644
--- a/aether/registration/root_server_select_stream.h
+++ b/aether/registration/root_server_select_stream.h
@@ -35,9 +35,9 @@
 namespace ae {
 class Aether;
 struct RootServerSelectStreamTestAccess;
+
 class RootServerSelectStream final : public ByteIStream {
  public:
-  static constexpr std::size_t kBufferCapacity = 2;
   using ServerChangedEvent = Event<void()>;
   using CloudErrorEvent = Event<void()>;
 
@@ -54,6 +54,9 @@ class RootServerSelectStream final : public ByteIStream {
   CloudErrorEvent::Subscriber cloud_error_event();
 
  private:
+  static constexpr auto kBufferCapacity = AE_ROOT_REG_SERVER_BUFFER_CAPACITY;
+  using Buffer = BufferWrite<DataBuffer, kBufferCapacity>;
+
   friend struct RootServerSelectStreamTestAccess;
 
   WriteAction* OnWrite(DataBuffer&& data);
@@ -65,7 +68,7 @@ class RootServerSelectStream final : public ByteIStream {
   AeContext ae_context_;
   PtrView<RegistrationCloud> cloud_;
 
-  BufferWrite<DataBuffer, kBufferCapacity> buffer_write_;
+  Buffer buffer_write_;
   // The next server priority to select. Registration server priorities must be
   // contiguous starting at zero; gaps are UB. This invariant and Cloud's
   // strict server collection capacity bound ensure this value never increments
diff --git a/aether/server_connections/client_server_connection.h b/aether/server_connections/client_server_connection.h
index 9d12ac87..b8e51bd7 100644
--- a/aether/server_connections/client_server_connection.h
+++ b/aether/server_connections/client_server_connection.h
@@ -17,6 +17,8 @@
 #ifndef AETHER_SERVER_CONNECTIONS_CLIENT_SERVER_CONNECTION_H_
 #define AETHER_SERVER_CONNECTIONS_CLIENT_SERVER_CONNECTION_H_
 
+#include "aether/config.h"
+
 #include "aether/ae_context.h"
 #include "aether/common.h"
 #include "aether/crypto/icrypto_provider.h"
@@ -35,9 +37,11 @@ class Server;
 class Channel;
 
 namespace client_server_connection_internal {
+static constexpr auto kBufferCapacity = AE_SERVER_CONNECTION_BUFFER_CAPACITY;
+
 class BufferedServerConnection : public ByteIStream {
  public:
-  static constexpr std::size_t kBufferCapacity = 10;
+  using Buffer = BufferWrite<DataBuffer, kBufferCapacity>;
 
   BufferedServerConnection(AeContext const& ae_context,
                            Ptr<Server> const& server);
@@ -48,7 +52,7 @@ class BufferedServerConnection : public ByteIStream {
   OutDataEvent::Subscriber out_data_event() override;
   void Restream() override;
 
-  BufferWrite<DataBuffer, kBufferCapacity> buffer_write;
+  Buffer buffer_write;
   ServerConnection server_connection;
 };
 }  // namespace client_server_connection_internal
diff --git a/aether/tele_compile_options.h b/aether/tele_compile_options.h
index ffcc29ca..4534daef 100644
--- a/aether/tele_compile_options.h
+++ b/aether/tele_compile_options.h
@@ -48,6 +48,15 @@ constexpr inline auto _compile_options_list = std::array{
     _OPTION(AE_UDP_PACKET_QUEUE_SIZE),
     _OPTION(AE_SUPPORT_TCP),
     _OPTION(AE_TCP_PACKET_QUEUE_SIZE),
+    _OPTION(AE_SERVER_CONNECTION_BUFFER_CAPACITY),
+    _OPTION(AE_ROOT_REG_SERVER_BUFFER_CAPACITY),
+    _OPTION(AE_P2P_MESSAGE_STREAM_BUFFER_CAPACITY),
+    _OPTION(AE_CLOUD_GET_CLOUD_ACTION_POOL_CAPACITY),
+    _OPTION(AE_CLOUD_GET_SERVERS_ACTION_POOL_CAPACITY),
+    _OPTION(AE_MODEM_NETWORK_OP_ACTION_POOL_CAPACITY),
+    _OPTION(AE_MODEM_WRITE_ACTION_POOL_CAPACITY),
+    _OPTION(AE_MODEM_TCP_PACKET_QUEUE_SIZE),
+    _OPTION(AE_MODEM_UDP_PACKET_QUEUE_SIZE),
     _OPTION(AE_SUPPORT_WEBSOCKET),
     _OPTION(AE_SUPPORT_HTTP),
     _OPTION(AE_SUPPORT_HTTP_OVER_TCP),
diff --git a/aether/transport/modems/modem_transport.cpp b/aether/transport/modems/modem_transport.cpp
index 8b1a0b73..e32224a5 100644
--- a/aether/transport/modems/modem_transport.cpp
+++ b/aether/transport/modems/modem_transport.cpp
@@ -185,8 +185,7 @@ WriteAction& ModemTransport::Write(DataBuffer&& in_data) {
 
 WriteAction& ModemTransport::WriteTcp(DataBuffer&& in_data) {
   auto& send_queue_manager =
-      std::get<PacketQueueManager<SendTcpAction, kTcpSendQueueSize>>(
-          packet_queue_manager_);
+      std::get<ModemTcpPacketQueueManager>(packet_queue_manager_);
 
   // Make TCP packet with its size at the beginning
   auto packet_data = std::vector<std::uint8_t>{};
@@ -212,8 +211,7 @@ WriteAction& ModemTransport::WriteTcp(DataBuffer&& in_data) {
 }
 WriteAction& ModemTransport::WriteUdp(DataBuffer&& in_data) {
   auto& send_queue_manager =
-      std::get<PacketQueueManager<SendUdpAction, kTcpSendQueueSize>>(
-          packet_queue_manager_);
+      std::get<ModemUdpPacketQueueManager>(packet_queue_manager_);
 
   auto* send_action =
       send_queue_manager.AddPacket(ae_context_, *this, std::move(in_data));
@@ -322,15 +320,11 @@ ModemTransport::PacketQueueManagerVar ModemTransport::MakePacketQueueManager(
   switch (endpoint.protocol) {
     case Protocol::kTcp: {
       return PacketQueueManagerVar{
-          std::in_place_type_t<
-              PacketQueueManager<SendTcpAction, kTcpSendQueueSize>>{},
-          ae_context};
+          std::in_place_type_t<ModemTcpPacketQueueManager>{}, ae_context};
     }
     default: {
       return PacketQueueManagerVar{
-          std::in_place_type_t<
-              PacketQueueManager<SendUdpAction, kTcpSendQueueSize>>{},
-          ae_context};
+          std::in_place_type_t<ModemUdpPacketQueueManager>{}, ae_context};
     }
   }
 }
diff --git a/aether/transport/modems/modem_transport.h b/aether/transport/modems/modem_transport.h
index 22210230..b162a862 100644
--- a/aether/transport/modems/modem_transport.h
+++ b/aether/transport/modems/modem_transport.h
@@ -21,24 +21,20 @@
 
 #if AE_SUPPORT_MODEMS
 #  define MODEM_TRANSPORT_ENABLED 1
-#  include <variant>
 #  include <optional>
+#  include <variant>
 
 #  include "aether/ae_context.h"
 #  include "aether/events/multi_subscription.h"
 
-#  include "aether/stream_api/istream.h"
 #  include "aether/modems/imodem_driver.h"
-#  include "aether/transport/packet_send_action.h"
-#  include "aether/transport/packet_queue_manager.h"
+#  include "aether/stream_api/istream.h"
 #  include "aether/transport/data_packet_collector.h"
+#  include "aether/transport/packet_queue_manager.h"
+#  include "aether/transport/packet_send_action.h"
 #  include "aether/write_action/failed_write_action.h"
 
 namespace ae {
-
-// TODO: add config
-static constexpr std::size_t kTcpSendQueueSize = 10;
-
 class ModemTransport final : public ByteIStream {
   class ModemSend : public PacketSendAction {
    public:
@@ -82,9 +78,17 @@ class ModemTransport final : public ByteIStream {
     Subscription send_sub_;
   };
 
+  static constexpr auto kTcpPacketQueueCapacity =
+      AE_MODEM_TCP_PACKET_QUEUE_SIZE;
+  static constexpr auto kUdpPacketQueueCapacity =
+      AE_MODEM_UDP_PACKET_QUEUE_SIZE;
+
+  using ModemTcpPacketQueueManager =
+      PacketQueueManager<SendTcpAction, kTcpPacketQueueCapacity>;
+  using ModemUdpPacketQueueManager =
+      PacketQueueManager<SendUdpAction, kUdpPacketQueueCapacity>;
   using PacketQueueManagerVar =
-      std::variant<PacketQueueManager<SendTcpAction, kTcpSendQueueSize>,
-                   PacketQueueManager<SendUdpAction, kTcpSendQueueSize>>;
+      std::variant<ModemTcpPacketQueueManager, ModemUdpPacketQueueManager>;
 
  public:
   ModemTransport(AeContext const& ae_context, IModemDriver& modem_driver,
diff --git a/aether/transport/packet_queue_manager.h b/aether/transport/packet_queue_manager.h
index 5ccd46a4..0921abf5 100644
--- a/aether/transport/packet_queue_manager.h
+++ b/aether/transport/packet_queue_manager.h
@@ -23,12 +23,13 @@
 #include <etl/circular_buffer.h>
 
 #include "aether/ae_context.h"
+#include "aether/common.h"
 #include "aether/transport/packet_send_action.h"
 
 #include "aether/transport/transport_tele.h"
 
 namespace ae {
-template <typename T, std::size_t MaxSize = 10>
+template <typename T, std::size_t MaxSize>
   requires(std::is_base_of_v<PacketSendAction, T>)
 class PacketQueueManager {
  public:
diff --git a/aether/transport/system_sockets/udp/udp.h b/aether/transport/system_sockets/udp/udp.h
index 7f7e7b5e..f176720c 100644
--- a/aether/transport/system_sockets/udp/udp.h
+++ b/aether/transport/system_sockets/udp/udp.h
@@ -33,11 +33,11 @@
 
 #    include "aether/poller/poller.h"
 #    include "aether/stream_api/istream.h"
-#    include "aether/transport/transport_tele.h"
-#    include "aether/transport/packet_send_action.h"
 #    include "aether/transport/packet_queue_manager.h"
-#    include "aether/write_action/failed_write_action.h"
+#    include "aether/transport/packet_send_action.h"
 #    include "aether/transport/system_sockets/sockets/isocket.h"
+#    include "aether/transport/transport_tele.h"
+#    include "aether/write_action/failed_write_action.h"
 
 namespace ae {
 namespace upd_internal {
diff --git a/aether/write_action/buffer_write.h b/aether/write_action/buffer_write.h
index 4b3a0baf..9d90fe78 100644
--- a/aether/write_action/buffer_write.h
+++ b/aether/write_action/buffer_write.h
@@ -71,7 +71,7 @@ class BufferedWriteAction final : public WriteAction {
 /**
  * \brief Buffers write requests until gate is not ready to accept them.
  */
-template <typename T, std::size_t MaxSize = 10>
+template <typename T, std::size_t MaxSize>
 class BufferWrite {
   struct BufferEntry {
     BufferedWriteAction wa;