From 9b60ad3617bf16b85343680f9e07cda3b26458e4 Mon Sep 17 00:00:00 2001
From: John Abraham <john.abraham.in@gmail.com>
Date: Thu, 15 Aug 2013 21:00:57 -0700
Subject: [PATCH] Update internet-stack-helper API for jitter and CHANGES.html

---
 CHANGES.html                                 | 13 +++++++------
 src/internet/helper/internet-stack-helper.cc | 12 +++++++-----
 src/internet/helper/internet-stack-helper.h  |  2 +-
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/CHANGES.html b/CHANGES.html
index 9e1b9b21f..2d7a0cfcb 100644
--- a/CHANGES.html
+++ b/CHANGES.html
@@ -71,11 +71,11 @@ us a note on ns-developers mailing list.</p>
       IPv6 to make an Autoconfigured address.</li>
   <li>IPv6 can now detect and use Path-MTU. See 
       examples/ipv6/fragmentation-ipv6-two-MTU.cc for an example.</li>
-  <li>Radvd application have a new Helper. See the updated 
+  <li>Radvd application has a new Helper. See the updated 
       examples/ipv6/radvd.cc for an example.</li>
-  <li>InternetStackHelper have two new functions:<tt>SetIpv4ArpJitter (bool enable)</tt>
+  <li>InternetStackHelper has two new functions:<tt>SetIpv4ArpJitter (bool enable)</tt>
       and <tt>SetIpv6NsRsJitter (bool enable)</tt> to enable/disable
-      the random jitter on IPv4's ARP and IPv6's NS/RS.</li>
+      the random jitter on the tranmission of IPv4 ARP Request and IPv6 NS/RS. </li>
 </ul>
 
 <h2>Changes to existing API:</h2>
@@ -134,9 +134,10 @@ or
   cmd.PrintHelp (std::cerr);
 </pre>
    </li>
-   <li>IPv4's ARP and IPv6's NS/RS are now issued with a random delay.
-       The delay is, by default, between 0 and 10ms.
-       This behaviour can be modify by using ArpL3Protocol's 
+   <li>IPv4's ARP Request and IPv6's NS/RS are now transmitted with a random delay.
+       The delay is, by default, a uniform random variable in time between 0 and 10ms.
+       This is aimed at preventing reception errors due to collisions during wifi broadcasts.
+       This behaviour can be modified by using ArpL3Protocol's 
        <tt>RequestJitter</tt> and Icmpv6L4Protocol's <tt>SolicitationJitter</tt>
        attributes or by using the new InternetStackHelper functions.
        </li>
diff --git a/src/internet/helper/internet-stack-helper.cc b/src/internet/helper/internet-stack-helper.cc
index 1b4fc1e75..a16259f6b 100644
--- a/src/internet/helper/internet-stack-helper.cc
+++ b/src/internet/helper/internet-stack-helper.cc
@@ -236,7 +236,7 @@ InternetStackHelper::InternetStackHelper ()
     m_ipv4Enabled (true),
     m_ipv6Enabled (true),
     m_ipv4ArpJitterEnabled (true),
-    m_ipv6NsRsEnabled (true)
+    m_ipv6NsRsJitterEnabled (true)
 
 {
   Initialize ();
@@ -273,7 +273,7 @@ InternetStackHelper::InternetStackHelper (const InternetStackHelper &o)
   m_ipv6Enabled = o.m_ipv6Enabled;
   m_tcpFactory = o.m_tcpFactory;
   m_ipv4ArpJitterEnabled = o.m_ipv4ArpJitterEnabled;
-  m_ipv6NsRsEnabled = o.m_ipv6NsRsEnabled;
+  m_ipv6NsRsJitterEnabled = o.m_ipv6NsRsJitterEnabled;
 }
 
 InternetStackHelper &
@@ -298,7 +298,7 @@ InternetStackHelper::Reset (void)
   m_ipv4Enabled = true;
   m_ipv6Enabled = true;
   m_ipv4ArpJitterEnabled = true;
-  m_ipv6NsRsEnabled = true;
+  m_ipv6NsRsJitterEnabled = true;
   Initialize ();
 }
 
@@ -334,7 +334,7 @@ void InternetStackHelper::SetIpv4ArpJitter (bool enable)
 
 void InternetStackHelper::SetIpv6NsRsJitter (bool enable)
 {
-  m_ipv6NsRsEnabled = enable;
+  m_ipv6NsRsJitterEnabled = enable;
 }
 
 int64_t
@@ -437,6 +437,7 @@ InternetStackHelper::Install (Ptr<Node> node) const
       if (m_ipv4ArpJitterEnabled == false)
         {
           Ptr<ArpL3Protocol> arp = node->GetObject<ArpL3Protocol> ();
+          NS_ASSERT (arp);
           arp->SetAttribute ("RequestJitter", StringValue ("ns3::ConstantRandomVariable[Constant=0.0]"));
         }
       // Set routing
@@ -457,9 +458,10 @@ InternetStackHelper::Install (Ptr<Node> node) const
 
       CreateAndAggregateObjectFromTypeId (node, "ns3::Ipv6L3Protocol");
       CreateAndAggregateObjectFromTypeId (node, "ns3::Icmpv6L4Protocol");
-      if (m_ipv6NsRsEnabled == false)
+      if (m_ipv6NsRsJitterEnabled == false)
         {
           Ptr<Icmpv6L4Protocol> icmpv6l4 = node->GetObject<Icmpv6L4Protocol> ();
+          NS_ASSERT (icmpv6l4);
           icmpv6l4->SetAttribute ("SolicitationJitter", StringValue ("ns3::ConstantRandomVariable[Constant=0.0]"));
         }
       // Set routing
diff --git a/src/internet/helper/internet-stack-helper.h b/src/internet/helper/internet-stack-helper.h
index 687f4551f..f4d16b06f 100644
--- a/src/internet/helper/internet-stack-helper.h
+++ b/src/internet/helper/internet-stack-helper.h
@@ -324,7 +324,7 @@ private:
   /**
    * \brief IPv6 IPv6 NS and RS Jitter state (enabled/disabled) ?
    */
-  bool m_ipv6NsRsEnabled;
+  bool m_ipv6NsRsJitterEnabled;
 };
 
 } // namespace ns3