diff --git a/apps/sbc/RegisterCache.cpp b/apps/sbc/RegisterCache.cpp
index c4a52eb3..61ec2c05 100644
--- a/apps/sbc/RegisterCache.cpp
+++ b/apps/sbc/RegisterCache.cpp
@@ -49,14 +49,14 @@ void AorHash::gbc(long int now,
 
       auto& binding = reg_it->second;
 
-      if (binding.reg_expire <= now) {
+      if (binding.get_expire() <= now) {
 
 	alias_list.push_back(binding.alias);
 	AorEntry::iterator del_it = reg_it++;
 
 	DBG("delete binding: '%s' -> '%s' (%li <= %li)",
 	    del_it->first.c_str(), binding.alias.c_str(),
-	    binding.reg_expire, now);
+	    binding.get_expire(), now);
 
 	it->second.erase(del_it);
 	continue;
@@ -341,7 +341,7 @@ void _RegisterCache::update(const string& alias, long int reg_expires,
     }
   }
   // and update binding
-  binding_it->second.reg_expire = reg_expires;
+  reg_cache_ht.set_expire(aor_e_it, binding_it, reg_expires);
 
   auto alias_e_it = id_idx.find(alias);
   // if no alias map entry, insert a new one
@@ -445,7 +445,7 @@ void _RegisterCache::update(long int reg_expires, const AliasEntry& alias_update
 	uri.c_str(), binding_it->second.alias.c_str());
   }
   // and update binding
-  binding_it->second.reg_expire = reg_expires;
+  reg_cache_ht.set_expire(aor_e_it, binding_it, reg_expires);
 
   lock_guard<AmMutex> _id_l(id_idx);
 
@@ -793,7 +793,7 @@ bool _RegisterCache::throttleRegister(RegisterCacheCtx& ctx,
     const string& uri = contact_it->uri_str();
 
     if(!getAlias(ctx.from_aor,uri,req.remote_ip,reg_binding) ||
-       !reg_binding.reg_expire) {
+       !reg_binding.get_expire()) {
       DBG("!getAlias(%s,%s,...) || !reg_binding.reg_expire",
 	  ctx.from_aor.c_str(),uri.c_str());
       return false; // fwd
@@ -804,8 +804,8 @@ bool _RegisterCache::throttleRegister(RegisterCacheCtx& ctx,
     contact_expires += now.tv_sec;
 
     if(contact_expires + 4 /* 4 seconds buffer */ 
-       >= reg_binding.reg_expire) {
-      DBG("%li + 4 >= %li",contact_expires,reg_binding.reg_expire);
+       >= reg_binding.get_expire()) {
+      DBG("%li + 4 >= %li",contact_expires,reg_binding.get_expire());
       return false; // fwd
     }
     
diff --git a/apps/sbc/RegisterCache.h b/apps/sbc/RegisterCache.h
index d9fe4fe6..b937f64f 100644
--- a/apps/sbc/RegisterCache.h
+++ b/apps/sbc/RegisterCache.h
@@ -33,22 +33,35 @@ using std::unique_ptr;
 
 struct RegBinding
 {
+private:
   // Absolute timestamp representing
   // the expiration timer at the 
   // registrar side
   long int reg_expire;
 
+public:
   // unique-id used as contact user toward the registrar
   string alias;
 
   RegBinding()
     : reg_expire(0)
   {}
+
+  long int get_expire() const {
+    return reg_expire;
+  }
+
+  friend class AorEntry;
 };
 
 // Contact-URI/Public-IP -> RegBinding
 class AorEntry : public unordered_map<string, RegBinding>
 {
+  void set_expire(const iterator& it, long int expire) {
+    it->second.reg_expire = expire;
+  }
+
+  friend class AorHash;
 };
 
 struct AliasEntry
@@ -141,6 +154,10 @@ class AorHash
   : public unordered_hash_map<string, AorEntry>
 {
 public:
+  void set_expire(const iterator& aor_it, const AorEntry::iterator& binding_it, long int expire) {
+    aor_it->second.set_expire(binding_it, expire);
+  }
+
   /* Maintenance stuff */
 
   void gbc(long int now, list<string>& alias_list);
diff --git a/apps/sbc/RegisterDialog.cpp b/apps/sbc/RegisterDialog.cpp
index ab82a374..aee04971 100644
--- a/apps/sbc/RegisterDialog.cpp
+++ b/apps/sbc/RegisterDialog.cpp
@@ -204,7 +204,7 @@ int RegisterDialog::fixUacContacts(const AmSipRequest& req)
       if(!reg_cache_reply)
 	continue;
 
-      if(is_a_dereg || !reg_binding.reg_expire) { // no contact with expires=0
+      if(is_a_dereg || !reg_binding.get_expire()) { // no contact with expires=0
 	reg_cache_reply = false;
       }
 
@@ -220,12 +220,12 @@ int RegisterDialog::fixUacContacts(const AmSipRequest& req)
       DBG("min_reg_expire = %u", min_reg_expire);
       DBG("max_ua_expire = %u", max_ua_expire);
       DBG("contact_expires = %lu", contact_expires);
-      DBG("reg_expires = %li", reg_binding.reg_expire - now.tv_sec);
+      DBG("reg_expires = %li", reg_binding.get_expire() - now.tv_sec);
 
       contact_expires += now.tv_sec;
 
       if(contact_expires + 4 /* 4 seconds buffer */ 
-	 >= reg_binding.reg_expire) {
+	 >= reg_binding.get_expire()) {
 	reg_cache_reply = false;
 	continue;
       }