[Ns-developers] [ns][MIP]Handover ARP problem

[Michal Lewandowski]

Hi all,

I’m doing some experiments with Mobile IP and I think I found a serious problem. 

I’m using standard tcl file and I see that the time of handover is much to long. 

After investigations I found out that handover ends when packet “message” is called.

I thing this is an ARP packet. When I set traffic to the Mobile Node I managed to solve this problem by calling arprequest() function by Foreign Agent every time MN tries to register.

The problem is when traffic is up, I mean when MN is a source. I tried calling arprequest() in several combinations, but with no positive results.

Does anybody know what is going on with this simulator (I’m using ns2-28). Why this problem occurs at all? And how to solve it? I think everyone working with Mobile IP is in the same situation. Or maybe this ARP problem is well known, maybe updating ARP table after registration request is not in the standard, it is not a part of basic SUN’s MIP model?

Thanks for help,

Michal

PS. Below there is ll:recv() function with my modifications. 

/*
This shall be added in arp.cc
MobileNode*
ARPTable::get_node_michu()
{
	return node_;
}
*/

void LL::recv(Packet* p, Handler* /*h*/)
{
	hdr_cmn *ch = HDR_CMN(p);
	hdr_arp	*ah = HDR_ARP(p);
	hdr_mip *miph = hdr_mip::access(p);
	hdr_ip *ip_h = hdr_ip::access(p);
        
	

	//char *mh = (char*) HDR_MAC(p);
	//struct hdr_sr *hsr = HDR_SR(p);

	/*
	 * Sanity Check
	 */
	assert(initialized());

	//if(p->incoming) {
	//p->incoming = 0;
	//}
	// XXXXX NOTE: use of incoming flag has been depracated; In order to track direction of pkt flow, direction_ in hdr_cmn is used instead. see packet.h for details.

	// If direction = UP, then pass it up the stack
	// Otherwise, set direction to DOWN and pass it down the stack
	if(ch->direction() == hdr_cmn::UP) {
		//if(mac_->hdr_type(mh) == ETHERTYPE_ARP)
		if(ch->ptype_ == PT_ARP){
			
			
			if(ah->arp_spa == 4194305) // I mean Mobile Node's IP here. Not very elegant way to do it
			{
				if(licznik < 10)
				{
					nsaddr_t src_arp = arptable_->get_node_michu()->address(); // this host's IP addr		
					nsaddr_t dst_arp = miph->ha_;           //Home Address of Mobile Node				
					arptable_->arprequest(src_arp, dst_arp, this);
				
					licznik++;
					//printf(" src_arp %d\n", src_arp);
					//printf(" dst_arp %d\n", dst_arp);
					//printf("arprequest %d\n", licznik);
				}
			}
			
			if(ah->arp_spa == 4194304) // I mean Mobile Node's IP here. Not very elegant way to do it
			{
				if(licznik2 < 10)
				{
					nsaddr_t src_arp = arptable_->get_node_michu()->address(); // this host's IP addr		
					nsaddr_t dst_arp = miph->ha_;           //Home Address of Mobile Node				
					arptable_->arprequest(src_arp, dst_arp, this);
				
					licznik2++;
					//printf(" src_arp %d\n", src_arp);
					//printf(" dst_arp %d\n", dst_arp);
					//printf("arprequest %d\n", licznik);
				}
			}
			
			if(ah->arp_spa == 8388608) // I mean Mobile Node's IP here. Not very elegant way to do it
			{
				if(licznik3 < 10)
				{
					nsaddr_t src_arp = arptable_->get_node_michu()->address(); // this host's IP addr		
					nsaddr_t dst_arp = miph->ha_;           //Home Address of Mobile Node				
					arptable_->arprequest(src_arp, dst_arp, this);
				
					licznik3++;
					//printf(" src_arp %d\n", src_arp);
					//printf(" dst_arp %d\n", dst_arp);
					//printf("arprequest %d\n", licznik);
				}
			}
			
			
			arptable_->arpinput(p, this);
			//printf("arpinput %d\n", licznik);
		}
		else
		{
			
			if((miph->type_ == MIPT_REG_REQUEST) || (miph->type_ == MIPT_REG_REPLY) || (miph->type_ == MIPT_SOL)) //in FA
			{
				nsaddr_t src = arptable_->get_node_michu()->address(); // this host's IP addr
				nsaddr_t dst = miph->ha_;           //Home Address of Mobile Node
				arptable_->arprequest(src, dst, this);
				
				//uptarget_ ? sendUp(p) : drop(p);
				//printf(" src %d\n", src);
				//printf(" dst %d\n", dst);
				//printf("uptarget_ MIPT_REG_REQUEST\n");
				
			}
			
			
			uptarget_ ? sendUp(p) : drop(p);
			//printf("uptarget_\n");
			
		}
		return;
	}
	
	
	if((miph->type_) == MIPT_REG_REQUEST)
	{
		//double local_time = Scheduler::instance().clock();
		//printf(" local_time MIPT_REG_REQUEST %.9f\n", local_time);

		//	printf("MIPT_REG_REQUEST %d \n", arptable_->get_node_michu()->address());
		nsaddr_t src_down = 4194305;                           //arptable_->get_node_michu()->address(); // this host's IP addr
		nsaddr_t dst_down = miph->coa_;                        //miph->coa_;
		arptable_->arprequest(src_down, dst_down, this);
	}
	else if((miph->type_) == MIPT_ADS)
	{
		//double local_time = Scheduler::instance().clock();
		//printf(" local_time MIPT_REG_REQUEST %.9f\n", local_time);
			
		nsaddr_t src_down = 4194305;                           //arptable_->get_node_michu()->address(); // this host's IP addr
		nsaddr_t dst_down = miph->coa_; 
		arptable_->arprequest(src_down, dst_down, this);
	}
	
	/*
	nsaddr_t src_down = 4194305;
	nsaddr_t dst_down = 8388608;
	arptable_->arprequest(src_down, dst_down, this);
	
	nsaddr_t src_down = 8388608;
	nsaddr_t dst_down = 4194305;
	arptable_->arprequest(src_down, dst_down, this);

	nsaddr_t src_down = 8388608;
	nsaddr_t dst_down = 4194304;
	arptable_->arprequest(src_down, dst_down, this);
	*/
	
	
	double local_time = Scheduler::instance().clock();
	if(local_time < 13)
	{
		printf(" time %.9f node %d packet %s\n", local_time, arptable_->get_node_michu()->address(), packet_info.name(ch->ptype()));
	}
	
	
	ch->direction() = hdr_cmn::DOWN;
	sendDown(p);
}


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