Network Working Group Jong Oh. Kim INTERNET-DRAFT SoongSil UNIV Expiration Date : August 1999 Y. Mun SoongSil UNIV Feburary 1999 Mobility Support in the Differentiated Services Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026 except for the right to produce derivative works. This document is an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." To view the entire list of current Internet-Drafts, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), ftp.nordu.net (Northern Europe), ftp.nis.garr.it (Southern Europe), munnari.oz.au (Pacific Rim), ftp.ietf.org (US East Coast), or ftp.isi.edu (US West Coast). The distribution of this document before its expiry date is unlimited. 0. Abstract This document provides a method to be able to support mobility service in the Differentiate Service Architecture[1]. For this service we used Mobile IP[2] as mobility scheme. So we define new functions and operations and we modify the header formats already defined in Mobile IP[2] suggested in IETF support under IPv4 and IPv6. Kim, Mun Expires August 1999 [Page 1] Internet Draft draft-kim-mobile-diff-00.txt Feburary 1999 1. Introduction Diff-Serv is a mechanism by which network service providers can offer differing levels of network service to different traffic, in so providing quality of service (QoS) to their customers. Because this mechanism has been deployed just for fixed hosts Diff-Serv have been suggested can not be satisfied with mobility service. The new mechanism this document describes is designed for user wants to have mobility service in the Internet. Mobile IP[2] is a modification to IP that allows nodes to continue to receive datagrams no matter where they happen to be attached to the Internet. It involves some additional control messages that allow the IP nodes involved to manage their IP routing tables reliably. For mobility support in the DS we adopts Mobile IP mechanism is already on the status of RFC (Request for comment) in the IETF(Internet Engineering Task Force). When we apply the Mobile IP in the DS new functions are required in Boundary router of DS. This document presents new functions under the IPv4 and IPv6 for mobility in DS model. One of issues we noticed adopting the Mobile IP is that there are different functions required according to Agent of Mobile IP is located in Boundary router of DS or is separated from Boundary router of DS. This document only considers that Agent functions and DS Edge Router functions are isolated and illustrates the mechanism in that situation. The document is organized as follows. In section 2 the document describes the network architecture we premise and operation for supporting mobility service in the Diff-Serv model under IPv4. In section 3 we define new mechanism for mobility support in IPv4 while section 4 illustrates a functioin needed for mobility service under IPv6 2. Mobility Support in DS of IPv4 In this section we will describe how transparent mobility service can be supported in the IPv4 while mobile host is away form Home Domain we define newly. We premise in this document that location of Agents defined in Mobile IP are located in subnetwork in each and there can be constructed more than two subneworks in a DS Domain. 2.1. Network Architecture Kim, Mun Expires August 1999 [Page 2] Internet Draft draft-kim-mobile-diff-00.txt Feburary 1999 The Network Architecture premised in this draft is same one defined in [1]. that is, there is DS Domain where DS Edge Node to separate DS Domains and connects with non-DS Domains are constructed in DS boundary. Functions of DS Edge Node suggested in [1] that are forwarding packets and traffic conditioning according to the DS codepoint defined by PHB groups are carried on identically. But one situation differs from [1] is that we premise mobile host that is located in DS Domain. That is shown in Figure 1. It explains that mobile host can be move out of the its own Domain. Home Domain +-----------------------+ | +-----+ | | |home | +---|--------+ | |agent|---------| Home Edge | | +--+---+ | Rouer | | ---|--|-------+- +---|-------|+ | | | | | | +------+ +--+--+ | | | |Mobile| |fixed| | +-+-------------+ | |host | |host | | | Foreign Edge | | +---\--+ +-----+ | | Router------|-----------+ +-------\---------------+ +---|-------+---+ | \ | | | \ | +--+----+ | \ Foreign | |Foreign| | \ Domain | | Agent | | \ | +----+--+ | \ | -------|--------|-- | \ | +-----+-+ +---+-+ | \ | |Mobile | |Fixed| | \ ==================|==>| Host | | host| | | +-------+ +-----+ | +-----------------------+ Figure 1 Mobile Ds Architecture One Domain can be constructed more than two subnetworks where Agent defined in [2] supports mobility service for mobile hosts. Although we take in the Mobile IP mechanism in subnetworks constructed in a domain. When mobile hosts move out of the Domain Mobile IP must be modified for transparent mobility service for mobile node. So we focus that how can be supported transparent mobility service in the case of movement between Domains. One of terminologies defined in this draft newly is the Home Domain and the Foreign Domain. Home Domain is the Domain for mobile host to contract service originally and get service first. Foreign Domain is Kim, Mun Expires August 1999 [Page 3] Internet Draft draft-kim-mobile-diff-00.txt Feburary 1999 the Domain for mobile host to stay when mobile host is away form Home Domain. Important components in this model are the Home Edge Router and Foreign Edge Router that have core functions for mobility service. Hone Edge Router is a router that offers function needed for transparent mobility service in the Home Domain of mobile host when mobile host moves from its own Domain to another Domain. And Home Edge Router also supports the functions as Edge router defined in [3] identically. Foreign Edge Router is a router that brings in mobility service for mobile host in a Domain to which mobile host moves from Home Domain. Of course Foreign Edge Router is also located in DS boundary as Edge router suggested in [3]. In another meaning Home Edge Router and Foreign Edge Router are router have a function of agent to be able to give the mobility service for mobile host. 2.2 Registration When mobile host which is communicating with a correspondent host moves out of subnetwork there are two cases considered. First case is that mobile host can just move between subnetwork in same Domain. In this case after mobile hosts detect its movement with advertisements Foreign Agent broadcasts it sends Registration message defined in [2] to Foreign Agent. Because we premise Foreign Agent already knows address of Edge routers that are located in a its own Domain by manual configuration Foreign Agent can compares address of Edge router it has with the field of Registration message mobile host sends contains address of Edge router. The field of Edge router address is one of the fields we have modified. If Foreign Agent has the address of Edge router contained in Registration message among its own Edge router list Foreign Agent decides that mobile host is being in its Home domain and forwards Registration message mobile host sent to Home Agent directly. But in the case of movement between Home Domain and Foreign Domain another procedures defined newly are needed. First mobile host makes an attempts to get Care-of-Address after migration from its Home Domain to Foreign Domain. After acquisition of Care-of-Address mobile host sends Registration message to Foreign Agent which is located in a subnetwork of Foreign Domain. Mobile host inserts address of its own Home Edge Router in Registration message and sends it to Foreign Agent. Foreign Agent receives Registration message mobile host sent decides that mobile host is being in a Foreign Domain moving out of its Home Domain because Foreign Agent has not found Edge router address contained in Registration message among Kim, Mun Expires August 1999 [Page 4] Internet Draft draft-kim-mobile-diff-00.txt Feburary 1999 Edge router List it has. Then Foreign Agent forwards Registration message to Foreign Edge router, not Home Agent directly after Foreign Agent set the N flag and inserts one of the Foreign Edge routers Addresses in Registra- tion message. Home Edge Router received Registration message starts to negotiate SLA[1] because N flag is set in Registration message. Here one assumption is that all Agents know address of Edge Routers through manual configuration. First step of negotiation is that Home Edge Router takes Registrat- ion message Foreign Edge router forwards in Foreign Domain. And Home Edge Router decides whether mobile host is one of the hosts it has given quality of service to. Next step is that Home Edge Router sends Traffic profile that is on quality of service level mobile host contracted to Foreign Edge Router if N flag is set. For above procedure the field of Foreign Edge Router address is needed in Registration message. So Home Edge Router can cognize which Foreign Edge Router takes care of the mobile host temporally through this field and can decide the Foreign Edge Router to which it must give the information of Traffic profile. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type |S|B|D|M|G|V|N| | Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Home Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Home Agent | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Care-of Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Identification + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Home Edge Router Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Foreign Edge Router Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extensions ... +-+-+-+-+-+-+-+- Flag N : It indicates that Foreign Agent require SLA negotiation between Home Edge router and Foreign Edge router Kim, Mun Expires August 1999 [Page 5] Internet Draft draft-kim-mobile-diff-00.txt Feburary 1999 Home Edge Router Address : It is necessary for Foreign Edge Router to send Registration message to Home Edge Router Foreign Edge Router Address : It is necessary for Home Edge Router to send traffic profile information of mobile host to Home Edge Router. figure 2 Registration Request Format of Mobile IP for mobility service So Foreign Edge Router can decide whether it can give the quality of service what Home Edge Router required for mobile host according to the Profile information Home Edge Router sent in its Domain. If the request of Home Edge Router is accepted Foreign Edge Router sends ACK message that indicates request acceptance to Home Edge Router. Therefor one of message we define is ACK message additionally. But if request is denied by Foreign Edge Router Home Edge Router is supposed to get NACK message. And then mobile host can be just given best-effort service in Foreign Domain. Through this procedure quality of service is given to mobile host in Foreign Domain and additionally Profile Information of mobile host should be cached in Guest list of Foreign Edge Router we suggest in addition. Fields needed in guest list are a IP address and port number and Care-of-Address , lifetime and Identification that are binding information of mobile host. Among these fields binding information is used for Route Optimizati- on[7] in order to make efficiency better. Procedure will be explained in section 2.2 in detail. Irrespective of the negotiation between Foreign Edge Router and Home Edge Router Registration message is arrived in Home Agent. By operation defined in Mobile IP after Registration is completed Reply message is sent to mobile host. 2.3 Delivering Datagrams If the correspondent host does not notice movement of mobile host wants to deliver datagrams to mobile host correspondent host sends datagrams using IP address of mobile host. Then Home Agent intercepts the datagrams correspondent host sent and encapsulates the datagrams. Encapsulated datagrams are forwarded to Foreign Edge Router. And If Traffic conditioning is necessary it is carried on by Foreign Edge Router. Therefor Home Edge Router and Foreign Edge Router are included in Tunneling. And If Remaking is needed Home Edge Router should not modify only DS filed in encapsulated IP header but also DS field in originated IP header. This is why adequate forwarding pattern has to be decided in the case of being router to mobile host after decapsulation Kim, Mun Expires August 1999 [Page 6] Internet Draft draft-kim-mobile-diff-00.txt Feburary 1999 When correspondent host delivers datagrams to mobile host is being in Home Domain triangular routing problem occurs. Although the problem can somehow be solved by Route Optimization[7] if mobile host is in Foreign Domain datagrams correspondent host sent has to be gone by way of Home Edge Router to get binding information from Home Agent of mobile host getting out of current Domain totally. This is another inefficiency. In this case it is more effient to use binding information in Guest list Edge Router has if Edge router can carry on the function of Home Agent partly. That is, instead of forwarding datagrams to Home Agent of Home Domain Foreign Edge Router returns binding information of mobile host using guest list it has because Foreign Edge Router can know that mobile host is one of the hosts it has given quality of service. So one of the function required in Edge Router is the decaptuaaltion. Then encapsulated datagrams Foreign Agent encapsulates can be decapsulated by Edge Router. After decapsulation Edge Router delivers datagrams to mobile host and returns binding information to correspondent host. Through this procedure propagation time can be saved. Next delivering datagrams correspondent host can use this binding information. In the case of delivering datagrams of mobile host to correspondent host mobile host can deliver datagrams to correspondent host directly using DS forwarding mechanism without any modification. 2.4 Cache Update When a mobile host moves to another Domain resources allocated for mobile host in former Domain where mobile host stayed has to be released. To release network resource Guest list update message we define is used whenever mobile host moves to another Domain. Because Edge Router allocates resources for mobile host temporally after mobile host moves to another Domain resource allocated has to be release using Guest list update message. The operation using Guest list update message is that mobile host should sends one to Foreign Edge Router mobile host know temporally. Especially a mobile host should sends one periodically to Foreign Edge Router has its traffic profile and contracts SLA temporally with Home Edge Router while Registration takes place. If Foreign Edge Router receives the Guest list update message before the timer Foreign Edge Router has expires the cache information in Guest list for mobile host should be kept. If Foreign Edge Router however does not receive the guest list update message in timeout it deems mobile host is away from current Domain and deletes the cache information in Guest list. Kim, Mun Expires August 1999 [Page 7] Internet Draft draft-kim-mobile-diff-00.txt Feburary 1999 One of issues we have considered is that there might be more than two Foreign Edge Routers in Domain. In this case the cache information of mobile host Foreign Edge Router has must be shared with other Edge Routers. Therefore the Foreign Edge Router receive the Guest list update message from mobile host should notify other Foreign Edge Route of cache information of mobile host available. 2.5 Deregistration When mobile host returns Home network mobile host set value of the lifetime to zero and send Registration message. Deregistration is done as above. It is defined in Mobile IP[2]. After deregisteration resource allocated in Foreign Edge Router has to be released. This is done by what we described in section 2.4. In the case that mobile host just returns to the Home Domain not exact Home network because mobile host detects whether it is in Home Domain or not by mechanism we described mobile host does not send Guest list update message to Foreign Edge Router. Therefor resource allocated is released after timeout. 3. Mobility Support in DS of IPv6 In this section we describe how mobility service can be supported when mobile host moves out of DS Domain where mobile host is given quality of service under IPv6[8] 3.1 Network Architecture When mobile host moves to another subnetwork it can find out its movement using movement detection[9] supported in IPv6 and obtains a Care-of-Address through the Stateless or Stateful address Autoconf- iguration[10]. Therefore one of the different situations is that the function of Foreign Agent is not necessary any more. With the exception of this the network architecture we have considered is that Home Domain and Foreign Domain exist as we defined in IPv4. And the functions of DS Edge Node suggested in [1] that are forwar- ding packets and traffic conditioing according to the DS codepoint defined by PHB groups are carried on identically. We premise mobile host that is located in DS Domain. One Domain can be constructed more than two subnetworks where Agent defined in [2] supports mobility service for mobile hosts. Although we take operation in [9] in subnetworks located in a domain when mobile host moves out of Kim, Mun Expires August 1999 [Page 8] Internet Draft draft-kim-mobile-diff-00.txt Feburary 1999 the Domain Mobile IP must be modified for transparent mobility service for mobile node. So we focus how can be supported transparent mobility service in the case of movement between Domains. 3.2 Registration We have considered two cases that mobile host is in Home Domain and it is in Foreign Domain as Registration procedure. First when mobile host moves between subnetworks in Home Domain it took the Care-of- Address sends Registration message to Home Agent. But one of the procedures needed is to decide whether mobile host is being in Home Domain or not before sends Registration message. This operation is as follows. First mobile host sends Router Solicitation message to router in subnetwork which mobile host found through Router Discovery offered in IPv6 after mobile host detects its movement using movement detection supported in IPv6. Router Solicitation message mobile host sends should be modified when mobile host uses this message for Registration. So we modify this message, and also Router Advertise- ment message for reply in Solicitation message. The fields added in message are one that is able to contain Edge Router Address of Home Domain. Mobile host compares Edge Router Address in Router Advertisement message with Edge router list it has. After this operation mobile host can decide whether it is in Home Domain or not. That is, if mobile host has same Edge Router Address in Edge Router list it is being in Home Domain. In this case mobile host just sends Registr- ation message to Home Agent. After this Registration procedure is exactly same with procedure defined in [9]. We premise here that every router in the Domain has Edge Route address. If there are more than two Edge Router in a Domain those should be contained in Router Advertisement message. But in the case that mobile host moves to Foreign Domain another procedures needed are as follows. If mobile host takes a Care-of- Address after movement detection Registration procedure starts. Of course it takes place for mobile host to send Router Solicitation message before Registration procedure starts. We define the Router Solicitation message mobile host sends to router first for Registra- tion which is a message to change a value of field in Router Solicit- ation message[11]. The message including changed field is shown in figure 3. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 Kim, Mun Expires August 1999 [Page 9] Internet Draft draft-kim-mobile-diff-00.txt Feburary 1999 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type =133 | Code=1 | Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Option code =1 |Option Length=1| | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sender's Link Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type : 133 , code : 1 Figure 3 Edge Router Solicitation Message for mobility service The values of the two fields, Type and code defined in RFC 2461 are 133 and 0 respectively. Using this option we define new Edge Router Solicitation message for Registration of mobile host as the value of Type and Code field is 133 and 1 respectively. The Router Advertisement message a router received the Edge Router Solicitation message should reply must contain Edge Router Address. A mobile host compares Edge Router List it has in default with Edge Router Address in Router Advertisement message it received. In the case that mobile host moves out of the Home Domain there is no Edge Router address matched. New option to contain Edge Router Address we suggest in the format of Router Advertisement message defined in RFC 2461 should be supplement to the options already defined, Source link-layer address option, MTU option and Prefix information option. That is, when router replies in Edge Router Solicitation new option should be extended in Router Advertisement message. Option consists of option code fields which value is 7 and option length which is variable. The reason why the value of option length is variable is that Edge Router Address router has may be more than two Address. And Edge Router Addresses fills the body of option part. Router Advertisement message to add new option is shown in figure 4. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type =134 | Code=0 | Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cur Hop Limit |M|O| Reserved | Router Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reachable Time | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Retrans Timer | Kim, Mun Expires August 1999 [Page 10] Internet Draft draft-kim-mobile-diff-00.txt Feburary 1999 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Option code |Option Length | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+| | Edge Router Address[i] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ....... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Edge Router Address[N] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option code : 7 option length : variable Edge router's Address[I] : Edge router IP Address of ith Figure 4 Router advertisement message for mobility service When a mobile host detects that it is in Foreign Domain through Router Advertisement message instead of mobile host does not sends Registration message to Home Agent directly mobile host sends Registration message with N flag set to Edge Router of Foreign Domain. It means that SLA negotiation initializes between Foreign Edge Router and Home Edge Router for quality of service level mobile host wants. If mobile host moves between subnetworks in Home Domain or non-DS Domain N flag has to be set to zero. In the case that mobile host moves between subnetowks in a same Foreign Domain whenever mobile host moves Registration message has not to be deliverd to Home Agent. Instead of, Foreign Edge Router plays a role as Home Agent temporally. Foreign Edge Router forwards Registration message from mobile host to Home Edge Router and starts SLA negotiation. SLA negotiation procedure is the same as we describe in IPv4. While SLA negotiation proceeds Registration message arrives in Home Agent. After SLA negotiation If mobile host can get quality of service mobile host information including binding information caches in Guest list in Foreign Edge Router. 3.3 Delivering Datagrams In the case that mobile host delivers datagrams correspondent host DS forwarding mechanism is enough for mobile host without any modification. But if correspondent host wants to deliver datagrams to mobile host a little modification is needed. If the correspondent host does not notice movement of mobile host correspondent host sends datagrams using original IP address of mobile host. Then Home Agent intercepts the datagrams correspondent Kim, Mun Expires August 1999 [Page 11] Internet Draft draft-kim-mobile-diff-00.txt Feburary 1999 host sent in Home Domain and encapsulates[12] the datagrams. Encapsulated datagrams are forwarded to mobile host. And If Traffic conditioning is necessary it is carried on between Home Edge Router and Foreign Edge Router holding datagrams. And If Remaking is needed Home Edge Router should only modify DS filed in encapsulated IP header. It is one of the difference with operation of IPv4. This is why de-capsulation is done in mobile host in IPv6. If Home Agent and correspondent host are located in different Domain and correspondent host and mobile host are being in same Domain we can use Foreign Edge Router as Foreign Agent in IPv4. This is, when mobile host just moves in Foreign Domain Registration message has not to be sends to Home Agent. Instead of, Foreign Edge Router manages location of mobile host using Guest list. What a figure 5 explains is that mobile host registers its location to Home Agent when mobile host moves to Foreign Domain. After Registration correspondent host does not know movement of mobile host tries to deliver datagrams. Home Domain |------------------+ | +-----+ | | |home | +---|--------+ | |agent|-----| Home Edge | | +-----+ | Rouer | | ------+---+---|--------+ | | | | | +--+--+ | | | |fixed| | ++-------------+ | |host | | | Foreign Edge| | +-----+ | | Router-----|-----------+ +------------------+ +-|----\-+/\\--+-----+ | | \ \ +---+---+ | Foreign | \ \ | Home | | Domain | \ \ | Agent | | | \ \ +-----+-+ | | --\--------\-----|--- | | +-\\/+--+ +-\----+-+ | | |Mobile | |corres- | | | | Host | |pondent | | | +-------+ | host | | +------------+--------+--+ Figure 5 Delivering Datagrams By the scheme of IPv6 already suggested datagrams correspondent host sends has to be via Home Agent first. Then first delivering mobile Kim, Mun Expires August 1999 [Page 12] Internet Draft draft-kim-mobile-diff-00.txt Feburary 1999 host received datagrams sends its binding information to correspond- ent host. If mobile host moves to another subnetwork in the same Domain frequently above procedure is not efficient. If Foreign Edge Router plays a role as Agent it can be solved. Thant is, datagrams correspondent host sent have not to be delivered to Home Agent, just to Foreign Edge Router. Foreign Edge Router receives the datagrams forwards these to mobile host. For this operation Foreign Edge Router should have the encapsulation function. 3.4 Cache Update If mobile host does not exist in current Foreign Domain resources allocated for mobile host in Foreign Domain where mobile host stayed has to be released. For deallocation of network resource making use of Update message including the timer is more efficient rather than using explicit signal whenever mobile host moves to another Domain. Because resources are allocated resources for mobile host temporally by Edge Router after mobile host moves to another Domain resource allocated has to be release using Guest list update message we define. The operation using Guest list update message is as follows. A mobile host should sends Guest list update message periodically to Foreign Edge Router has its traffic profile and contracts SLA temporally with Home Edge Router while Registration takes place. If Foreign Edge Router receives the Guest list update message before the timer Foreign Edge Router has expires the cache information in Guest list for mobile host should be kept for a lifetime. If Foreign Edge Router however does not receive the guest list update message in timeout it decides that mobile host moves to another Domain and deletes the cache information of mobile host in Guest list. One of considerations we have is that because there might be more than two Foreign Edge Routers in Domain in this case the cache information of mobile host Foreign Edge Router has must be shared with other Edge Routers. Therefore the Foreign Edge Router receives the Guest list update message from mobile host should forwards update message mobile host sent to other Foreign Edge Route of cache information of mobile host available. 3.5 Deregistration After mobile host returns Home network it set a value of the lifetime to zero and sends Registration message[2] for Deregistration. After deregisteration resource allocated in Foreign Edge Router has to be released. This is done by using Guest list update message described Kim, Mun Expires August 1999 [Page 13] Internet Draft draft-kim-mobile-diff-00.txt Feburary 1999 in section 3.4 Because a mobile host is able to detect whether it is in Home domain or not by mechanism we described in section 3.2 when mobile host returns to a Home domain not a exact home network mobile host does not send Guest list update message to Foreign Edge Router. Then resource allocated is released after timeout. 4. Conclusion Over the past several years there has been a considerable amount of research within the field quality of service for real time and multimedia data service in the Internet. Among these research Differentiated Service model suggested in Diff-Serv working group of IETF is being upheld recently. Because this model just however considers the fixed host for quality of service mobility service required gradually in the Internet can not be supported. So to be satisfied with quality of service and mobility service in the Inte- rnet at the same time we suggested new operation and modified some header format already designed applying Mobile IP defined in IETF. Through what we design mobility service and mobility service can be realized in the Internet. 5. Reference [1] S. Blake , D. Black, M. Carlson, E. Davies, Z. Wang, and W. Weiss. An Architecture for Differentiated Services. RFC2475 December 1998 [2] C. Perkins, IP Mobility Support. RFC2002. October 1996 [3] D. Durham and F. Reichmeyer. Requirements of Diff-serv Boundary Routers. draft-bernet-diffedge-01.txt. Internet Draft. November, 1998. Work in Progress [4] Blake, Yoram Bernet, James Binder, Steven Blake, Mark Carlson, Srinivasan Keshav, Elwyn Davies Borje Ohlman, Dinesh Verma, Zheng Wang and Walter Weiss . A Framework for Differentiated Services. draft-ietf-diffserv-framework-01.txt. InternetDraft. October, 1998. Work in Progress. [5] C. Perkins . IP encapsulation in IP RFC2003, October 1996 [6] W. Simpson. IP in IP tunneling. RFC1835, October 1995 [7] Charles Perkins and David B. Johnson. Route Optimization in Kim, Mun Expires August 1999 [Page 14] Internet Draft draft-kim-mobile-diff-00.txt Feburary 1999 Mobile IP. draft-ietf-mobileip-optim-07.txt. Internet Draft. November 1997. Work in Progress [8] S. Deering, R. Hinden and Nokia Internet Protocol, Version 6 Specification(IPv6). RFC2460. December 1998. [9] David B. Johnson and Charles Perkins. Mobility Support in IPv6. draft-ietf-mobileip-ipv6-07.txt. Internet Draft. November 1998. Work in Progress [10] S.Thomson and T.Narten. IPv6 Stateless Address Autoconfiguration. RFC2462. December 1998. [11] T. Narten, E. Nordmark and W. Simpson. Neighbor Discovery for IP Version 6 (IPv6). RFC2461. December 1998 [12] A. Conta S. Deering. Generic Packet Tunneling in IPv6 Specification. RFC2473. December 1998 6. Author Information JongOh Kim Email: fido@computing.soongsil.ac.kr Tel: 082-2-820-0689 1-1 Sanddo 5 Dong Dongjack-Gu, Seoul Korea Y.Mun Email: Mun@computing.soongsil.ac.kr Tel: 082-2-820-0676 1-1 Sanddo 5 Dong Dongjack-Gu, Seoul Korea Kim, Mun Expires August 1999 [Page 15] Internet Draft draft-kim-mobile-diff-00.txt Feburary 1999