diff --git a/build/src.pro b/build/src.pro
index 105b35a..5777716 100644
--- a/build/src.pro
+++ b/build/src.pro
@@ -25,7 +25,8 @@ HEADERS += \
     ../include/rw_lock.h \
     ../include/tls_pointer.h \
     ../src/route.hpp \
-    ../src/channel.hpp
+    ../src/channel.hpp \
+    ../src/id_pool.hpp
 
 SOURCES += \
     ../src/shm.cpp \
diff --git a/include/circ_queue.h b/include/circ_queue.h
index 84b4ffc..85c2b66 100644
--- a/include/circ_queue.h
+++ b/include/circ_queue.h
@@ -41,25 +41,25 @@ public:
     }
 
     std::size_t connect() {
-        if (elems_ == nullptr) return error_count;
+        if (elems_ == nullptr) return invalid_value;
         if (connected_.exchange(true, std::memory_order_relaxed)) {
             // if it's already connected, just return an error count
-            return error_count;
+            return invalid_value;
         }
         return elems_->connect();
     }
 
     std::size_t disconnect() {
-        if (elems_ == nullptr) return error_count;
+        if (elems_ == nullptr) return invalid_value;
         if (!connected_.exchange(false, std::memory_order_relaxed)) {
             // if it's already disconnected, just return an error count
-            return error_count;
+            return invalid_value;
         }
         return elems_->disconnect();
     }
 
     std::size_t conn_count() const {
-        return (elems_ == nullptr) ? error_count : elems_->conn_count();
+        return (elems_ == nullptr) ? invalid_value : elems_->conn_count();
     }
 
     bool connected() const {
@@ -116,6 +116,7 @@ public:
             if (size == 0) throw std::invalid_argument { "Invalid size." };
             for (std::size_t i = 0; i < static_cast<std::size_t>(size); ++i) {
                 queue* que = ques[i];
+                if (que == nullptr) continue;
                 if (que->elems_ == nullptr) throw std::logic_error {
                     "This queue hasn't attached any elem_array."
                 };
diff --git a/include/def.h b/include/def.h
index 4edbaa7..ad90dd1 100644
--- a/include/def.h
+++ b/include/def.h
@@ -27,8 +27,8 @@ using uint_t = typename uint<N>::type;
 // constants
 
 enum : std::size_t {
-    error_count = (std::numeric_limits<std::size_t>::max)(),
-    data_length = 16
+    invalid_value = (std::numeric_limits<std::size_t>::max)(),
+    data_length   = 16
 };
 
 // concept helpers
diff --git a/include/ipc.h b/include/ipc.h
index fd30548..c5e37af 100644
--- a/include/ipc.h
+++ b/include/ipc.h
@@ -57,8 +57,9 @@ public:
     void swap(route& rhs);
     route& operator=(route rhs);
 
-    bool         valid() const;
-    char const * name () const;
+    bool         valid () const;
+    char const * name  () const;
+    handle_t     handle() const;
 
     route clone() const;
 
diff --git a/src/channel.hpp b/src/channel.hpp
index ec47dba..0468831 100644
--- a/src/channel.hpp
+++ b/src/channel.hpp
@@ -2,17 +2,28 @@
 
 #include <atomic>
 #include <string>
+#include <array>
+#include <limits>
+#include <shared_mutex>
+#include <mutex>
+#include <unordered_map>
 
 #include "def.h"
 #include "shm.h"
+#include "rw_lock.h"
+
+#include "id_pool.hpp"
 
 namespace {
 
 using namespace ipc;
 
+#pragma pack(1)
 struct ch_info_t {
-    std::atomic<uint_t<8>> ch_acc_; // only support 256 channels with one name
+    rw_lock lc_;
+    id_pool ch_acc_; // only support 255 channels with one name
 };
+#pragma pack()
 
 } // internal-linkage
 
@@ -27,12 +38,19 @@ public:
     shm::handle h_;
     route       r_;
 
-    ch_info_t* info() {
-        return static_cast<ch_info_t*>(h_.get());
+    std::string n_;
+    std::size_t id_;
+
+    std::unordered_map<std::size_t, route> rts_;
+
+    ~channel_(void) { rts_.clear(); }
+
+    ch_info_t& info() {
+        return *static_cast<ch_info_t*>(h_.get());
     }
 
     auto& acc() {
-        return info()->ch_acc_;
+        return info().ch_acc_;
     }
 };
 
@@ -69,9 +87,7 @@ bool channel::valid() const {
 }
 
 char const * channel::name() const {
-    std::string n { impl(p_)->h_.name() };
-    n.pop_back();
-    return n.c_str();
+    return impl(p_)->n_.c_str();
 }
 
 channel channel::clone() const {
@@ -83,38 +99,85 @@ bool channel::connect(char const * name) {
         return false;
     }
     this->disconnect();
-    using namespace std::literals::string_literals;
-    if (!impl(p_)->h_.acquire((name + "_"s).c_str(), sizeof(ch_info_t))) {
+    if (!impl(p_)->h_.acquire(((impl(p_)->n_ = name) + "_").c_str(), sizeof(ch_info_t))) {
         return false;
     }
-    auto cur_id = impl(p_)->acc().fetch_add(1, std::memory_order_relaxed);
-    impl(p_)->r_.connect((name + std::to_string(cur_id)).c_str());
+    {
+        std::unique_lock<rw_lock> guard { impl(p_)->info().lc_ };
+        if (impl(p_)->acc().invalid()) {
+            impl(p_)->acc().init();
+        }
+        impl(p_)->id_ = impl(p_)->acc().acquire();
+    }
+    if (impl(p_)->id_ == invalid_value) {
+        return false;
+    }
+    impl(p_)->r_.connect((name + std::to_string(impl(p_)->id_)).c_str());
     return valid();
 }
 
 void channel::disconnect() {
+    if (!valid()) return;
+    {
+        std::unique_lock<rw_lock> guard { impl(p_)->info().lc_ };
+        impl(p_)->acc().release(impl(p_)->id_);
+    }
+    impl(p_)->rts_.clear();
     impl(p_)->r_.disconnect();
     impl(p_)->h_.release();
 }
 
 std::size_t channel::recv_count() const {
-    return 0;
+    return impl(p_)->r_.recv_count();
 }
 
-bool channel::send(void const * /*data*/, std::size_t /*size*/) {
-    return false;
+bool channel::send(void const * data, std::size_t size) {
+    return impl(p_)->r_.send(data, size);
 }
 
-bool channel::send(buff_t const & /*buff*/) {
-    return false;
+bool channel::send(buff_t const & buff) {
+    return impl(p_)->r_.send(buff);
 }
 
-bool channel::send(std::string const & /*str*/) {
-    return false;
+bool channel::send(std::string const & str) {
+    return impl(p_)->r_.send(str);
 }
 
 buff_t channel::recv() {
-    return {};
+    if (!valid()) return {};
+    std::array<queue_t*, id_pool::max_count> ques;
+    return ipc::multi_recv([&] {
+        std::array<std::size_t, id_pool::max_count> acqeds;
+        std::size_t counter = 0;
+        std::unordered_map<std::size_t, route> cache;
+        // get all acquired ids
+        {
+            std::shared_lock<rw_lock> guard { impl(p_)->info().lc_ };
+            impl(p_)->acc().for_each([&](std::size_t id, bool acquired) {
+                if (id == impl(p_)->id_) return;
+                if (acquired) {
+                    acqeds[counter++] = id;
+                }
+            });
+        }
+        // populate route cache & ques
+        for (std::size_t i = 0; i < counter; ++i) {
+            auto id = acqeds[i];
+            auto it = impl(p_)->rts_.find(id);
+            // it's a new id
+            if (it == impl(p_)->rts_.end()) {
+                it = cache.emplace(id, (impl(p_)->n_ + std::to_string(id)).c_str()).first;
+                queue_of(it->second.handle())->connect();
+            }
+            // it's an existing id
+            else it = cache.insert(impl(p_)->rts_.extract(it)).position;
+            // get queue of this route
+            ques[i] = queue_of(it->second.handle());
+        }
+        // update rts mapping
+        impl(p_)->rts_.swap(cache);
+        return std::make_tuple(ques.data(), counter);
+    });
 }
 
 } // namespace ipc
diff --git a/src/id_pool.hpp b/src/id_pool.hpp
new file mode 100644
index 0000000..a3d3400
--- /dev/null
+++ b/src/id_pool.hpp
@@ -0,0 +1,56 @@
+#include <cstring>
+
+#include "def.h"
+
+namespace ipc {
+
+class id_pool {
+public:
+    enum : std::size_t {
+        max_count = (std::numeric_limits<uint_t<8>>::max)() // 255
+    };
+
+private:
+    uint_t<8> cursor_ = 0;
+    uint_t<8> block_[max_count] {};
+
+public:
+    void init() {
+        for (std::size_t i = 0; i < max_count;) {
+            i = block_[i] = static_cast<uint_t<8>>(i + 1);
+        }
+    }
+
+    bool invalid() const {
+        static id_pool inv;
+        return std::memcmp(this, &inv, sizeof(id_pool)) == 0;
+    }
+
+    bool empty() const {
+        return cursor_ == max_count;
+    }
+
+    std::size_t acquire() {
+        if (empty()) {
+            return invalid_value;
+        }
+        std::size_t id = cursor_;
+        cursor_ = block_[id]; // point to next
+        block_[id] = 0;       // clear flag
+        return id;
+    }
+
+    void release(std::size_t id) {
+        block_[id] = cursor_;
+        cursor_ = static_cast<uint_t<8>>(id); // put it back
+    }
+
+    template <typename F>
+    void for_each(F&& fr) {
+        for (std::size_t i = 0; i < max_count; ++i) {
+            fr(i, block_[i] == 0);
+        }
+    }
+};
+
+} // namespace ipc
diff --git a/src/ipc.cpp b/src/ipc.cpp
index 644bab4..1094153 100644
--- a/src/ipc.cpp
+++ b/src/ipc.cpp
@@ -5,14 +5,10 @@
 #include <cstring>
 #include <algorithm>
 #include <utility>
-//#include <shared_mutex>
-//#include <mutex>
 #include <atomic>
 
 #include "def.h"
 #include "circ_queue.h"
-//#include "rw_lock.h"
-//#include "tls_pointer.h"
 
 namespace {
 
@@ -83,7 +79,7 @@ void disconnect(handle_t h) {
 std::size_t recv_count(handle_t h) {
     auto que = queue_of(h);
     if (que == nullptr) {
-        return error_count;
+        return invalid_value;
     }
     return que->conn_count();
 }
diff --git a/src/route.hpp b/src/route.hpp
index 4558cf5..9bdfc07 100644
--- a/src/route.hpp
+++ b/src/route.hpp
@@ -42,13 +42,17 @@ route& route::operator=(route rhs) {
 }
 
 bool route::valid() const {
-    return (impl(p_)->h_ != nullptr);
+    return (handle() != nullptr);
 }
 
 char const * route::name() const {
     return impl(p_)->n_.c_str();
 }
 
+handle_t route::handle() const {
+    return impl(p_)->h_;
+}
+
 route route::clone() const {
     return { name() };
 }
diff --git a/test/test_circ.cpp b/test/test_circ.cpp
index 2ba10b6..1c72b49 100644
--- a/test/test_circ.cpp
+++ b/test/test_circ.cpp
@@ -124,12 +124,12 @@ struct test_cq<ipc::circ::queue<T>> {
 
     cn_t* connect() {
         cn_t* queue = new cn_t { ca_ };
-        [&] { QVERIFY(queue->connect() != ipc::error_count); } ();
+        [&] { QVERIFY(queue->connect() != ipc::invalid_value); } ();
         return queue;
     }
 
     void disconnect(cn_t* queue) {
-        QVERIFY(queue->disconnect() != ipc::error_count);
+        QVERIFY(queue->disconnect() != ipc::invalid_value);
         QVERIFY(queue->detach() != nullptr);
         delete queue;
     }
diff --git a/test/test_ipc.cpp b/test/test_ipc.cpp
index dbff110..089e83b 100644
--- a/test/test_ipc.cpp
+++ b/test/test_ipc.cpp
@@ -122,6 +122,7 @@ private slots:
     void test_send_recv();
     void test_route();
     void test_route_performance();
+    void test_channel();
 } unit__;
 
 #include "test_ipc.moc"
@@ -388,4 +389,30 @@ void Unit::test_route_performance() {
     test_performance<1, 10>::start();
 }
 
+void Unit::test_channel() {
+    std::thread t1 {[&] {
+        ipc::channel cc { "my-ipc-channel" };
+        for (std::size_t i = 0;; ++i) {
+            ipc::buff_t dd = cc.recv();
+            if (dd.size() < 2) return;
+            QCOMPARE(dd, datas__[i]);
+        }
+    }};
+
+    std::thread t2 {[&] {
+        ipc::channel cc { "my-ipc-channel" };
+        while (cc.recv_count() == 0) {
+            std::this_thread::yield();
+        }
+        for (std::size_t i = 0; i < (std::min)(100, LoopCount); ++i) {
+            std::cout << "sending: " << i << "-[" << datas__[i].size() << "]" << std::endl;
+            cc.send(datas__[i]);
+        }
+        cc.send(ipc::buff_t { '\0' });
+        t1.join();
+    }};
+
+    t2.join();
+}
+
 } // internal-linkage