Double Hierarchal Mobile Mpls Managing Mobility And Fast Handoff Computer Science Essay

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In this paper we propose a new handoff scheme within two subnets. The idea supports the fast handoff and minimum end to end delay in the hierarchal Mobile MPLS. The proposed idea can easily be implemented inside the subnet and within the subnet. By giving an algorithm for fast hand off and improvement in the fast signaling has been provided. The algorithm is based new idea known as Double HMMPLS implements within two subnets and in side the subnet. Minimum handoff delay and by minimizing end to end delay it is better than the previous techniques.

In Today's internet mobility is the hot issue. Every mobile change its location over time. As for the real time application and enhancing the speed and QoS issue the MPLS has been deployed. So MPLS should support the mobility. So the concept of mobile MPLS was introduced to solve the mobility management problems. The further enhancement was Hierarchal Mobile MPLS. This was categorized as the reformative, Adaptive HMPLS and Dynamic HMPLS. In all these ideas the issues like fast handoff, minimum end to end delay was discussed. This paper mainly focused on the fast handoff between two subnets and reducing the end to end delay for the quality of service. MPLS is the scheme for the packet forwarding using labels. Mobility management is the great issue in the MPLS. Initially the MPLS was treated same as the Simple mobile IP communication but it does fulfill the requirement of speed and fast handoff for the real rime applications. The Solution was Hierarchal Mobile MPLS which improves the end to end delay and hand off latency for the real time applications. But the problem still persists and does not meet the actual requirement for the least handoff delay and end to end delay. Many solutions proposed for the solution but the area still needs many improvements. In this paper we are using the new idea that provides fast handoff inside the domain or inside a subnet using the Adaptive HMMPLS proposed in [1] and also with in two domains when a MN moves from one subnet to another subnet by defining another hierarchy of the FDA. This idea also defines a threshold value for the hierarchy for FDA. The whole idea is called as the Double Hierarchal Mobile MPLS.


The idea of Hierarchal Mobile MPLS was introduced by adding an additional agent called foreign domain agent. The basic concept was that there may be more than one FA in one subnet and can be handled by just single FDA. HMMPS minimize the end to end delay and provides the fast handoff between the FAs [2]. Mobile host determines whether it is in home or foreign domain when it receives an agent advertisement message broad cast by FA. If mobile host is in foreign domain then it acquire a CoA from the FA then it request for the registration with FA. The FA forwards this request to FDA instead of HA. FDA.HA request for label by LDP.The label mapping procedure ends and message arrive at FDA the LSP from FDA to FA is established.

But the disadvantage of the idea proposed in [2] has drawback that if the FDA is far away from FA, the handoff latency still could be long and not appropriate for real time applications such as video, voice or pervasive devices. The solution was Dynamic HMMPLS [3]. This provides the QoS and minimum handoff delay in wireless networks based on HMMPLS. The major advantage of Dynamic Hierarchical Mobile MPLS are that the dynamic distribution architecture is more reliable, Buffering of incoming packet at MN during handoff packets does not loss or reduced, Balance traffic load in the network is established using dynamic setup of LSP from AFA to FA.

In [3] we conclude that DHMM is the protocol for the mobility management in wireless networks. End to end delay of the packet is reduced by optimizing the forwarding path. Minimum bandwidth is required by using DHMM while finding the path.

The idea of dynamic HMMPLS has some advantages over static HMMPLS. The length of forwarding chain was controlled by setting a threshold value. On the other hand the disadvantage of this technique was additional signaling overhead resulting a lot of bandwidth consumption. Another disadvantage was that appointing a threshold value inside the subnet but the between two subnet this fact was ignored Which again cause a lot of delay when the Mobile node MN as well the FA and FDA move far away from the home agent. The solution of this problem is proposed in this paper.

When we move from one sub network to another having same similar foreign domain registration request is sent to new FA which is further forwarded to FDA and Label request message is sent back to FDA .new LSP from FDA to FA2 is established but LSP from HA to FDA is not changed this is the advantage that the HMMPLS do not set a new LSP from HA.

MH may send the old FA of new COA during handoff by using an update message which allow old FA to bind with new MH.

Hierarchical Mobile MPLS scheme is capable of fast handoff. This technique further leads us to fast signaling process when a MH moves to foreign network or domain.

In hierarchical Mobile MPLS foreign Domain Agent (FDA) is introduced in each MPLS domain. Figure 1 shows the architecture of Hierarchical Mobile MPLS [2].

The idea for the fast handoff and fast signaling was propos as shown in figure

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Figure 1. Hierarchical Mobile MPLS Architecture

There is no idea for the communication between two FDAs and when the MN moves from one subnet to another FDA is changed the above idea do not handle that fact efficiently. In this case when we move from one FDA to another FDA2 have to communicate with the HA as shown in figure above


The integration of Reformative HMPLS [1] into reformative MPLS provides the fast registration within the subnet. The figure shows the basic idea for the adoptive MPLS. in this case we have better use of FDA. As mobile node continuously changing its domain and at the same time FA will change. The previous binding of LSP will release and the MN will connect to FDA of the Subnet without any connection for the pervious FA. So the handoff delay of the new FA will smaller and the major advantage of this technique is minimum handoff delay within the domain.

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Figure2. Adaptive HMPLS Architecture


For meeting with today's and future requirement with high increment of mobile users demanding high bandwidth we need to ensure minimum latency period for handoff from one subnet to another or with in the APs of a domain with durable connection establishment. We mention earlier we also required minimum end to end delay for meeting the quality parameters. Our idea is based on double scheme hierarchal mobile MPLS. We propose the connection establishment scheme while MN moving from one subnet to another neighbor network

Fast handoff

MN request for CoA by using equivalence class FA assign CoA to mobile Node and forward that to the FDA the new location MN. Now within the network when MN moves from FA1 to FA2 the new FA connects with FDA but there is no need to inform the HA about the change. This ensure the minimum handoff delay within the subnet and the idea was

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Figure.3 Double-HMPLS Architecture Fast Handoff

proposed in [1] But when the MN moves from one subnet to another the whole connection was re established which cause a delay as Net2 is far away from HA as shown in figure. In case that the number of networks increases the distance elongates and the delay increases as well. We propose an algorithm for the connection establishment when MN moves from Subnet 1 to Subnet2.

Now if the mobile node crosses three subnets then a threshold value is set. When threshold will reach the connection establishment between HA and new FDA will taken place from the beginning same as with the FDA1 and FDA4 will directly connect to the HA and inform HA about the new location of MN

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Figure 4. Registration between two FDA's Dynamic-HMPLS Architecture

MN moves from FDA1 to FDA2 it must should have the FDA1 address ot the address of the previous foreign domain agent.

FA1 of subnet2 informs the FDA2 and provides it the previous FDA address

FDA2 will inform to FDA1 about the new location of MN. It is obvious that FDA2 is nearer to FDA1.

FDA1 will inform to the HA about the new location of MN and at the same time it sends the HA to the FDA2.

HA of the MN will directly connect to the FDA2 using the shortest path or minimum delay path and the communication will direct between HA and FDA2.


The above scheme may cause some signaling overhead on the network but the division of the tunneling signals between HA and FDA and then FDA to next FDA divides the signal overhead. Due to parallel signaling idea the connection establishment may be faster. As after threshold value three the new FDA and HA will calculate the shortest path again which will cause the minimum end to end delay. Due to the fact of moving from one domain to another or from one subnet to another the MH may come nearer to the HA. And if we do not set any threshold value the handoff delay may become larger but the MN may be nearer to the HA. So the idea for setting threshold cause the reduce that overhead and cause the minimum end to end delay.


If MN is nearer to HA in the new subnet it will cause minimum delay in handoff as well as it provides fast signaling. If the HA and new FDA or FDA4 are more far than the previous then the HA will communicate by using the shortest as propose in the first step. The new calculation of the path allows the calculation of shortest path again between HA and MN.


In this paper, we propose the Double hierarchal mobile MPLS. This idea also includes the adaptive HMMPLS to provide the fast handoff within the subnet and reduce the signaling overhead. But within two subnets that idea does not work so our propose idea provide the fast handoff within two FDA's. the use of threshold value set as three cause the fast connection re-establishment and allowed two subnets to calculate the shortest path again from the HA which cause the minimum end to end delay. Fast handoff and minimum handoff delay provide the efficiency for the communication and can be implemented for the real time applications. So the Double HMMPLS can be implemented for the existing HMMPLS.