diff --git a/drsm/claim.go b/drsm/claim.go
index 523a847..0d99812 100644
--- a/drsm/claim.go
+++ b/drsm/claim.go
@@ -12,16 +12,38 @@ import (
 
 func (d *Drsm) podDownDetected() {
 	logger.DrsmLog.Infoln("started Pod Down goroutine")
+
 	for p := range d.podDown {
 		logger.DrsmLog.Infof("pod Down detected %v", p)
-		// Given Pod find out current Chunks owned by this POD
-		pd := d.podMap[p]
+
+		// Safely get pod entry
+		d.podMapMutex.RLock()
+		pd, found := d.podMap[p]
+		d.podMapMutex.RUnlock()
+
+		if !found || pd == nil {
+			logger.DrsmLog.Warnf("pod %s not found in podMap", p)
+			continue
+		}
+
+		// Copy chunk IDs while holding read lock
+		pd.mu.RLock()
+		chunkIDs := make([]int32, 0, len(pd.podChunks))
 		for k := range pd.podChunks {
-			d.globalChunkTblMutex.Lock()
+			chunkIDs = append(chunkIDs, k)
+		}
+		pd.mu.RUnlock()
+
+		// Process chunks without holding pod lock
+		for _, k := range chunkIDs {
+
+			d.globalChunkTblMutex.RLock()
 			c, found := d.globalChunkTbl[k]
-			d.globalChunkTblMutex.Unlock()
+			d.globalChunkTblMutex.RUnlock()
+
 			logger.DrsmLog.Debugf("found: %v chunk: %v", found, c)
-			if found {
+
+			if found && c != nil {
 				go c.claimChunk(d, pd.PodId.PodName)
 			}
 		}
diff --git a/drsm/drsm.go b/drsm/drsm.go
index 8068e9a..d296d28 100644
--- a/drsm/drsm.go
+++ b/drsm/drsm.go
@@ -35,10 +35,12 @@ type chunk struct {
 }
 
 type podData struct {
-	PodId         PodId            `bson:"podId,omitempty" json:"podId,omitempty"`
-	Timestamp     time.Time        `bson:"time,omitempty" json:"time,omitempty"`
-	PrevTimestamp time.Time        `bson:"-" json:"-"`
-	podChunks     map[int32]*chunk `bson:"-" json:"-"` // chunkId to Chunk
+	PodId         PodId
+	Timestamp     time.Time
+	PrevTimestamp time.Time
+
+	mu        sync.RWMutex
+	podChunks map[int32]*chunk
 }
 
 type Drsm struct {
@@ -77,14 +79,21 @@ func (d *Drsm) ConstuctDrsm(opt *Options) {
 		}
 		d.resourceValidCb = opt.ResourceValidCb
 	}
+
 	d.chunkIdRange = 1 << (d.resIdSize - 10)
 	logger.DrsmLog.Debugf("chunkId in the range of 0 to %v", d.chunkIdRange)
+
 	d.localChunkTbl = make(map[int32]*chunk)
 	d.globalChunkTbl = make(map[int32]*chunk)
 	d.podMap = make(map[string]*podData)
-	d.podDown = make(chan string, 10)
 	d.scanChunks = make(map[int32]*chunk)
-	d.globalChunkTblMutex = sync.Mutex{}
+
+	d.podDown = make(chan string, 10)
+
+	// No explicit initialization required, but fine to keep
+	d.globalChunkTblMutex = sync.RWMutex{}
+	d.podMapMutex = sync.RWMutex{}
+
 	d.initIpam(opt)
 
 	// connect to DB
diff --git a/httpwrapper/httpwrapper.go b/httpwrapper/httpwrapper.go
index 7a40404..050acd3 100644
--- a/httpwrapper/httpwrapper.go
+++ b/httpwrapper/httpwrapper.go
@@ -12,6 +12,7 @@ import (
 	"os"
 	"time"
 
+	"github.com/5GC-DEV/util-cdac/logger"
 	"github.com/pkg/errors"
 	"golang.org/x/net/http2"
 	"golang.org/x/net/http2/h2c"
@@ -57,10 +58,17 @@ func NewHttp2Server(bindAddr string, preMasterSecretLogPath string, handler http
 		return nil, errors.New("server needs handler to handle request")
 	}
 
-	h2Server := &http2.Server{
+	/*h2Server := &http2.Server{
 		// TODO: extends the idle time after re-use openapi client
 		IdleTimeout: 1 * time.Millisecond,
+	}*/
+	h2Server := &http2.Server{
+		IdleTimeout: 60 * time.Second,
 	}
+	logger.UtilLog.Infof(
+		"HTTP2 IdleTimeout=%v",
+		h2Server.IdleTimeout,
+	)
 	server := &http.Server{
 		Addr:    bindAddr,
 		Handler: h2c.NewHandler(handler, h2Server),
diff --git a/middleware/3gpp_Sbi_Request_Info.go b/middleware/3gpp_Sbi_Request_Info.go
new file mode 100644
index 0000000..90061b1
--- /dev/null
+++ b/middleware/3gpp_Sbi_Request_Info.go
@@ -0,0 +1,49 @@
+package middleware
+
+import (
+	"net/http"
+	"sync"
+
+	"github.com/5GC-DEV/util-cdac/logger"
+	"github.com/gin-gonic/gin"
+)
+
+var requestCache sync.Map
+
+func IdempotencyMiddleware() gin.HandlerFunc {
+	return func(c *gin.Context) {
+
+		if c.Request.Method != http.MethodPost {
+			c.Next()
+			return
+		}
+
+		requestInfo := c.GetHeader("3gpp-Sbi-Request-Info")
+
+		if requestInfo != "" {
+			logger.UtilLog.Infof(
+				"Received idempotency key=%s method=%s path=%s",
+				requestInfo,
+				c.Request.Method,
+				c.Request.URL.Path,
+			)
+		}
+
+		if requestInfo == "" {
+			c.Next()
+			return
+		}
+
+		if _, exists := requestCache.Load(requestInfo); exists {
+			c.JSON(http.StatusConflict, gin.H{
+				"error": "duplicate request detected",
+			})
+			c.Abort()
+			return
+		}
+
+		requestCache.Store(requestInfo, true)
+
+		c.Next()
+	}
+}