I will be explaining about proxy mobile ipv6 it is a network-based mobility management protocol, I will be explaining about the terminologies and how does proxy mobile ipv6 work what is the exact problem that we will resolve with proxy mobile ipv6 how it basically works so it’s the concept and the advantages of proxy mechanical proxy mobile ipv6 is a network-based mobility management protocol and the main thing that we see in this keyword is proxy mobile ipv6 so it is an IP mobility solution which uses mobile ipv6 and also is a proxy.
Proxy Mobile ipv6
let’s talk about Mobile ipv6, Mobile ipv6 is IP mobility solution which allows the mobile node to move from one network this is the one access router to the other access router and to maintain a connection by giving a new IP address that is the care of address so if the mobile node is connected to this access adapter it will have a pair of address one when it changes then it gets a new care if it does not care if it is, so proxy mobile ipv6 uses mobile ipv6 so there is a concept of care of address but it is a network based mobility management protocol so the solution of IP mobility is implemented in the network and the mobile node is not involved in the IP mobility solution, it is not aware of what’s going so how can we achieve mobile ipv6 as a network based mobility management solution so the idea is to use one of the elements in network as a proxy for the mobile unit so one of the elements in the network will act as a proxy for the mobile node and the care of interest will not be assigned to the mobile node rather the care of address will be with the proxy for the mobile node so it may be the access around it so here of address will be not will not guess and the mobile so the proxy mobile ipv6 solution is a mobile ipv6 solution where one of the network elements acts as a proxy for the mobile node now if we see the elements are the terminologies that we use in the mobile ipv6 mobile ipv6 we have the corresponding node who is sending the data to the mobile node and the mobile node is connected to access router and mobile node has home agent and now if we look at the elements or the terminologies used in the proxy mobile ipv6 architecture we have the corresponding node which is communicating with the mobile node and we have the local mobility anchor which is equivalent to the home agent in mobile ipv6 and mobile access gateway which typically resides with the access router or which may be a function in the access router which keeps track of the mobile node and the domain where the proxy mobile ipv6 is implemented is called the proxy mobile ipv6 domain or localized mobility domain so there are two names here if we look into more details of each of these elements the local mobility anchor has a data structure which maintains the binding cache entry of the mobile model in mobile ipv6 the binding cache entry was maintained by the home agent the same data structure is present in the local mobility anchor but it is slightly extended for the proxy mobile ipv6 so if we look at the extended elements few of the elements that are added to binding cache entry data structure and the mobile node ID so this is in the LMA so ulema contains the binding cache entry which has the mobile node ID home network prefix is a prefix assigned by the LMA to the mobile node the Mac that’s the Mac to which the mobile node is connected and the flags that indicate that this is a proxy binding update which was received and for that proxy binding update the binding cache entry was made so we will see all the due dates in the future in proxy mobile ipv6 the mobile access gateway actually acts as a proxy for the mobile node so the details of mobile access gateway are present in the binding cache entry and also in the mobile ipv6 the binding cache entry had details like clear offenders so basically the binding cache entry has the details that is used to reach the mobile node so the care of address was there in the mobile ipv6 and the care of address here will be the address of the Mac because Mac is now acting as a proxy for the mobile node and that details will be there in the binding cache entry the Mac also has a data structure which is the binding update list the major difference between the proxy mobile ipv6 and the mobile ipv6 is this binding update live studies in mobile ipv6 the binding update list was maintained by the mobile node so the binding update list was Italy Mobile the details in binding update list in mobile diffuse it was something like care of address home address the refresh rate the expiry time of the binding update and all those details were there in the binding update list and the same binding update list is maintained by the mobile access gateway but with some additional information like the interface in the Mac to which the mobile node is connected and also the element the local mobility anchor serving this mobile all these details will be there will be binding update list and it is maintained by the Mac for the mobile not in proxy mobile ipv6
When a Mobile Node (MN) enters the proxy Mobile ipv6 domain it attaches itself to the access link provided by the Mobile Access Gateway (MAG) The MAG then identifies the MN and checks if it (MN) is authorized to use the proxy Mobile ipv6 service If the MN is authorized then the MAG will acquire the MN ID. That is the unique ID to identify the MN It could be the MAC address and this is acquired through a Router Solicitation message The Router Solicitation message is sent by the Mobile Node. to the MAG upon receiving the Router Solicitation message It sends a Proxy Binding Update (PBU) to the local mobility anchor (LMA) and the proxy binding update will contain the details of the MN That is the Mobile ID and the MAG details and that would be required for the Binding Cache Entry upon receiving the Proxy Binding Update LMA will check if the binding cache entry data-structure already has the details for this MN. If NOT it will create an entry in the binding cache entry data structure with an MN-Id and it will create a home network prefix The proxy binding update has a flag to indicate that it is not a binding update…Proxy Mobile ipv6 rather a Proxy binding- update sent by the MAG Which is for the PMIPV6 service the additional details, the proxy binding update contains is the access link technology used by the MN the hand-off indicator says whether the hand-off is between the MAG so the MN moved from one MAG to the other MAG or is it between the interface of the MN so if the MN has two interfaces through which it can connect to the MAG….Proxy Mobile ipv6 (two different technologies) even that hand-off can be indicated in PMIPV6 that is about the Proxy Binding Update upon receiving such a PBU the local mobility anchor will check if it is if the PBU is according to the proxy Mobile ipv6 specification or if it is not then that local mobility anchor will reject the proxy binding update so there will be no registration in the binding cache entry if the LMA accepts the PBU then it will check the Binding Cache Entry (BCE) data structure if the MN is already present …Proxy Mobile ipv6 so based on the mobile node ID It (LMA) will check if the entry is already present in the data structure if not it (LMA) will create a new entry in the data structure and it will assign an HN-Prefix for the MN there is also a flag in the BCE which indicates this is a proxy registration the Link information to the mobile node that is the MAG details through what address …can the MN be reached from the LMA So in short… After accepting the PBU LMA will allocate an HN-prefix and then it (LMA) will create a BCE which is this one and sets up a tunnel A bi-directional tunnel to the MAG and sends a proxy binding acknowledgment to the MAG…where this is the CoA of the MN so this is a Proxy CoA of the MN the proxy binding acknowledgment will contain the HN-Prefix which will be used to identify the MN in the proxy domain…. proxy Mobile ipv6 domain so the HN-Prefix will be the unique identifier to identify the MN in the entire proxy Mobile ipv6 domain So the address of the MN is the HN-Prefix and it will not change when the MN changes from one MAG to the other MAG these are the steps in PMIPV6 when the MN enters the PMIPV6 domain so basically… it (MN) receives the router advertisement message with the HN-Prefix so until the bi-directional tunnel is set-up the MAG will not send a Router Advertisement (RA) in response to the Router Solicitation message So now if the MN moves from this MAG to the next MAG so when the mobile node changes the MAG again a router solicitation messages are sent to the MAG so now it’s for the MAG-2 and the MAG 2 will send a proxy binding update to the LMA… the same LMA and the LMA will check the BCE data structure (LMA) finds the MN-ID MN-ID …Proxy Mobile ipv6..so it will change the details so the MAG address will change and the CoA… proxy CoA will also change and after that, it will create a new..ahh.. it (LMA) will set-up a new bi-directional tunnel with the new MAG for this particular MN so the bidirectional tunnel will be with the MAG-2…so the CoA has changed but the address to identify the mobile node in the proxy mobile ipv6 domain.. remains the same that is the HN-Prefix.. when the mobile node leaves one of the MAG’s it detects that the mobile node is unreachable so this MN is unreachable for this MAG when it detects an MN is unreachable MAG will send an MN de-registration message to the local mobility anchor (LMA) and the LMA will start a timer for that particular MN especially the timer to decide …how long the entry for the MN should be there in the BCE data structure so there can be two possibilities when a node is un-reachable One… It (MN) has changed the MAG within the PMIPV6 domain or It (MN) is not reachable at all…. So, if the timer expires then the Binding Cache Entry for that MN is removed from the LMA ahh…and if that MN is registered through a new MAG then the binding cache entry (BCE) remains but with a new CoA…the Proxy CoA And the new MAG details that is how the registration and de-registration of the mobile nodes are done when the MN moves from one access router to the other access router or the MN moves out of the PMIPV6 domain with all these details…the question still remains is Why do we need a bi-directional tunnel? and How does the correspondent node… which was having communication with the mobile node keep the connection active even after the MN has changed the access router? to answer this question I have copied an image from Wikipedia so if we look at the image… any packet that the MN sends to the Correspondent Node (CN) will be received by the MAG and MAG will send the packets to the LMA LMA on the other side of the tunnel so through the bi-directional tunnel the packet will be sent from the MAG to the LMA…Proxy Mobile ipv6 The LMA after receiving the packets … will remove the outer header and sent the packets to the destination that is the correspondent node and when the Packets are coming from the CN will send the packets to the home address of the MN… and not directly to the MAG or the MN….Either it (CN) will send to the Home Address of the MN which is the LMA which will forward the packets to the MAG through the bi-directional tunnel and the MAG will de-capsulate the packet intending for the MN and send it to the HN-Prefix if the Mobile Node (MN) changes the MAG For example…Proxy Mobile ipv6 ..Mobile Access Gateway 2 (MAG2) is present here..the MN moves from here to here then a new bi-directional tunnel is created and the CN can still send the packets to the same address and the LMA..that is te Local Mobility Anchor.. will handle the hand-off that has occurred during that time so the mobile node is also unaware of the change of the CoA and also the CN (is unaware of the change in CoA) so the CN keeps sending the packets to LMA and the LMA will send it to the right /correct MAG so…why do we need PMIPV6 or…what are the advantages? so one of them is …Proxy Mobile ipv6 if the PMIPV6 is implemented by the service provider then the MN can change the Access Router…so it can go from one access router to the other Access router without changing the IP address and also… without any software or hardware modifications to the protocol stack of the MN. so the MN is completely independent of any changes in the Network Infrastructure the other advantage is.. this protocol allows building a common network to accommodate various access technologies Like …WiMAX…3GPP 3GPP2 or Wireless LAN to show one of the examples… I have taken an image from the Cisco website … in this image we can see the Proxy Mobile ipv6 used in the WiFi network … so basically after the firewall there is a local mobility anchor (LMA) this is the home agent for the mobile nodes in the WiFi network so if the WiFi access point is changed then the MNs IP address will not change so the CN which is outside the PMIPV6 domain will send the packet to the Home Agent that is the LMA and so we can see the PMIPV6 protocol and the level 2 and the 802.11 this is a simple wifi example… of the architecture… of how the PMIPV6 can be used One of the exceptions is… if the CN is within the proxy Mobile ipv6 domain … so somewhere below this MAG then the packets are directly sent to the MAGs within the PMIPV6 to which the MN is connected rather than sending to the LMA so that’s the ONLY time…when the packets are sent directly to the MAG rather than to the LMA for more details on PMIPV6