One document matched: draft-nomad-mobileip-filters-03.txt

Differences from draft-nomad-mobileip-filters-02.txt



   Mobile IP Working Group                      N. A. Fikouras (editor) 
   INTERNET DRAFT                                            A. Udugama 
   Expires: October 2003                                 A. J. Koensgen 
                                                               C. Goerg 
                                              ComNets-ikom, Uni. Bremen 
                                                               W.Zirwas 
                                                        J. M. Eichinger 
                                                             Siemens AG 
                                                             April 2003 
                                      
                                      
                Filters for Mobile IPv4 Bindings (NOMADv4) 
                    draft-nomad-mobileip-filters-03.txt 
    
    
   Status of this Memo 
    
   This document is an Internet-Draft and is in full conformance 
   with all provisions of Section 10 of RFC2026. 
    
    
   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. 
    
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   at any time.  It is inappropriate to use Internet-Drafts as 
   reference material or to cite them other than as "work in progress." 
    
   The list of current Internet-Drafts can be accessed at 
        http://www.ietf.org/ietf/1id-abstracts.txt 
   The list of Internet-Draft Shadow Directories can be accessed at 
        http://www.ietf.org/shadow.html. 
    
    
   Abstract 
    
   Filters for Mobile IPv4 bindings enables mobile nodes to associate 
   one or more Filters with mobility bindings during their 
   establishment (registration, binding update). Flows that match a 
   Filter will be processed as defined by the Filter. In this manner, 
   it is possible for a mobile node to distribute flows among its 
   available points of attachment or to request that such flows are 
   dropped before traversing the Internet fabric, with or without 
   notification to their source. Finally, it is possible for a mobile 
   node to select whether it wishes to turn off routing optimization 
   for specific communications in order to avoid giving away its 
   location. 
    
    
    
    
    
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Table of Contents 
 
   1 Introduction.....................................................3 
   2 Terminology......................................................4 
   3 NOMAD Protocol Overview..........................................5 
 3.1 Protocol Description.............................................5 
 3.2 Model of Operation...............................................7 
   4 Backwards compatibility with RFC3344.............................9 
   5 Associating Filters with Mobility Bindings......................10 
 5.1 Mobile Node Considerations......................................10 
  Creating a new mobility binding with Filters.......................10 
  Replacing a Filter of a mobility binding by Index..................10 
  Adding new Filters to an existing mobility binding.................11 
  Renewing a mobility binding with Filters...........................11 
  Flushing all Filters or deleting a Filter from a mobility binding..11 
  Transferring a Filter between mobility bindings....................11 
 5.2 Filtering Agent Considerations..................................11 
  Home Agent Considerations..........................................12 
  Filters For Mobile IPv4 Bindings Registration Flag.................13 
 Regional Registration Considerations................................13 
  GFA/RFA Considerations.............................................13 
   6 NOMAD Extensions to RFC3344 Registration Messages...............13 
 6.1 Behavior Aggregate Filters (BAF) Extension......................15 
 6.2 Protocol Extension..............................................15 
 6.3 Source Address Extension........................................16 
 6.4 Source Network Extension........................................16 
 6.5 Source Port Extension...........................................17 
 6.6 Source Port Range Extension.....................................17 
 6.7 Destination Port Extension......................................18 
 6.8 Destination Port Range Extension................................18 
 6.9 Free-Form Extension.............................................19 
 6.10 Filter Target Extension........................................20 
 6.11 Filter Control Extension.......................................20 
 6.12 Filter Reply Extension.........................................21 
 Code Values for Filter Reply Extension..............................21 
   7 Routing Optimization Extensions.................................22 
 7.1. Routing Optimization Extension for Simultaneous Bindings.......22 
   8 Intellectual Property Considerations............................22 
   9 Acknowledgements................................................23 
   References........................................................23 
   A. Changes from Previous Versions.................................23 
   Authors' Addresses................................................24 
 
 
 
 
 
     
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1 Introduction 
    
   This document extends the Mobile IPv4 [1] protocol by providing the 
   means for mobile nodes that have requested simultaneous bindings to 
   notify Filtering Agents (Mobile IPv4 entities that can maintain 
   simultaneous bindings with Filters) of an association between 
   Filters and specific mobility bindings. As such, traffic intercepted 
   by, or originating from a Filtering Agent will be filtered and 
   individual flows will be handled as indicated by the control 
   information of the Filter. In the most typical scenario, individual 
   flows will be redirected to the (collocated) care-of address 
   indicated by the respective binding. This enables mobile nodes to 
   distribute active flows among their available points of attachment. 
   Alternatively, the mobile node may request when registering bindings 
   and filters that it does not wish to receive certain flows (it 
   wishes to have them dropped, with or without notification to source) 
   or to restrict flows for which it wishes to receive routing 
   optimization services. This is done in order to avoid giving away 
   the mobile nodeÆs location. 
    
   Home Agents are unable to distinguish between individual flows and 
   therefore redirect all intercepted traffic for a mobile node to the 
   (collocated) care-of address indicated by its binding. Consequently, 
   as the binding is updated with every hand-off, the total of a mobile 
   node's active flows are redirected to the most recently registered 
   (collocated) care-of address. Furthermore, if a mobile node requests 
   for simultaneous bindings, it will receive at each registered 
   (collocated) care-of address a duplicate copy of every active flow. 
   However, a mobile node that maintains multiple points of attachment 
   may wish to associate certain flows with specific access interfaces. 
   As these access interfaces vary their (collocated) care-of address a 
   mobile node should be able to perform a Mobile IPv4 (IP-layer) hand-
   off for only a subset of its active flows. 
    
   A functionality similar to the one described earlier can be provided 
   through the routing optimization extension [3] whereby the mobile 
   node is enabled to communicate directly with a correspondent node 
   (CN), bypassing the Home Agent. In that case, it is possible for the 
   mobile node to register a different (collocated) care-of address 
   with each CN, therefore associating all of a Correspondent Node's 
   communications with one of its points of attachment. However, with 
   this approach it is not possible to distribute the communications of 
   a given Correspondent Node between multiple points of attachment. 
   Correspondent Nodes, just like mobility agents, are equally unable 
   to distinguish between individual flows in spite of being their 
   origin. 
    
   An additional problem that arises in routing optimization conditions 
   is caused by the fact that Home Agents may inconsiderately issue 
   Binding Updates to all Correspondent Nodes, thus revealing the 
   mobile nodeÆs position. This process occurs even without some prior 
   security association between the Home Agent and the Correspondent 
   Node. As such, malicious Correspondent Nodes with the ultimate 
   purpose of tracking a mobile node may at arbitrary time periods 
     
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   query its Home Agent about the mobile nodeÆs current position. With 
   the help of filters for Mobile IPv4 bindings it is possible to 
   define a set of criteria matched only by communications for which a 
   mobile node would like to have routing optimization. 
    
   Filters for bindings require that a mobile node includes in its 
   registration requests or binding updates a list of Filters. In this 
   manner, Filtering Agents (Correspondent Nodes, Home or Mobility 
   Agents) become aware of the relationship between certain flows and 
   specific bindings. However, the existence of those Filters does not 
   affect in any way the mobile node's choice on the point of 
   attachment to be utilized for the return path. 
    
   In order to provide simultaneous bindings to Correspondent Nodes 
   with routing optimization support, the 'S' bit is introduced in the 
   binding update message. The consideration presented in this document 
   are collectively referred to as the NOMADv4 Extension. 
    
    
2 Terminology 
    
   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in 
   this document are to be interpreted as described in RFC-2119 [2]. 
    
   This document uses the following terms: 
    
   Domain   A collection of networks sharing a common network  
            administration. 
    
   Home domain 
            As defined in [5]. 
    
   Visited domain 
            The domain where the mobile node has one or more points of 
            attachment. 
    
   Home Agent (HA) 
            As defined in [1]. 
    
   Correspondent Node (CN) 
            As defined in [1]. 
    
   Gateway Foreign Agent (GFA) 
            As defined in [5]. 
    
   Regional Foreign Agent (RFA) 
            As defined in [5]. 
    
   Home Network 
            As defined in [1]. 
    
   Mobile Node (MN) 
            As defined in [1]. 
     
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   Mobility Binding 
            As defined in [1]. 
    
   Filtering Agent (FLA) 
            Mobile IPv4 entities that can maintain Filters for mobility  
            bindings such as the HA, RFA, GFA or CNs when routing  
            optimization is present. 
    
   Filter Module (FLM) 
            The smallest module from which complex Filters are  
            defined. 
    
   Filter (FL) 
            A collection of Filter Modules and control information  
            describing how a flow(s) should be handled. 
    
   Filtering Request (FLRQ) 
            Mobile IPv4 signaling (registration request, binding 
   update)  
            with the purpose of establishing a new mobility binding 
            that contains one or more Filters. 
    
   Filtering Reply (FLRP) 
            Mobile IPv4 signaling (registration reply, binding  
            acknowledgment) for returning the result of a Filtering  
            Request. 
    
   Default Filter (DB) 
            A special Filter applicable for all flows not matching any  
            other Filter. Is either defined by mobile node or  
            automatically allocated from Filtering Agents to the  
            lowest defined Index of 0. 
    
   Idle Mobility Binding (IMB) 
            A mobility binding without Filters. 
    
    
3 NOMADv4 Protocol Overview 
    
   This section provides an overview of how Filters for Mobile IPv4 
   bindings can be realized. 
    
3.1 Protocol Description 
    
   Mobile nodes that wish to associate Filters with an acquired 
   (collocated) care-of address are required to issue a registration 
   request or binding update including a list of Filters that indicate 
   which flows are associated with the registered (collocated) care-of 
   address. Such signaling is termed as Filtering Requests. 
    
   A Filter is consisted of one or more Filter Modules and is 
   terminated by a Filter Target Extension. A Filter Module may contain 
   several predicates. There is an OR relationship between predicates 
     
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   of a Filter Module. Moreover, there is an AND relationship between 
   Filter Modules of the same Filter. Consequently, in order for a flow 
   to match a Filter it is required to qualify for all of the Filter 
   Modules contained in the Filter. 
    
   With the help of the Filter Target Extension, the FilterÆs purpose 
   can be defined. It contains the FilterÆs Index, and a Target. The 
   Index identifies uniquelly a Filter for a given mobile node while 
   the Target indicates how a flow should be handled when it matches 
   the Filter (i.e. drop, forward). 
    
   A mobile node may define more than one Filters for a specific 
   mobility binding. The declaration of these Filters may take place 
   during one or more Filtering Requests. In the case of overlapping 
   Filters, the one with the highest Index is considered applicable.  
    
   Filter management is performed with the help of the Filter Control 
   Extension. One or more such extensions may be included in any 
   Filtering Request interleaving with any Filter declarations. The 
   purpose of the Filter Control Extension is to delete or refresh one 
   or more Filters or to define the Index of the Default Filter. 
    
   Filtering Requests will be processed by one or more Filtering 
   Agents. A Filtering Agent can be any Mobile IPv4 entity that can 
   maintain mobility bindings with Filters, like a HA, RFA, GFA or a CN 
   when routing optimization is supported.  
    
   Flows that fail to match any of the defined Filters are handled as 
   defined by the Default Filter. If a mobile node fails to promptly 
   define a Default Filter or if the associated mobility binding 
   expires then a new one will automatically be configured by each 
   involved Filtering Agent to the lowest possible Index of 0. 
   Different Filtering Agents may apply different Default Filter 
   definitions, however it is recommended that the Default Filter be 
   associated with the mobility binding with the longest outstanding 
   lifetime with the Target set to forward. 
    
   A mobile node may issue Filters corresponding to flows that do not 
   yet exist. When such a flow is initiated it will be handled by the 
   Filtering Agents as indicated by the respective Filter. 
    
   The rules by which a mobile node decides on the set of Filters are 
   considered beyond the scope of this document. The extensions 
   presented in this document do not affect in any way the mobile 
   nodeÆs choice on the point of attachment to be used when returning 
   traffic. 
    
   A Filtering Agent that receives a Filtering Request is required to 
   establish a mobility binding and set up a tunnel as per [1]. Filters 
   and Filter Control Extensions contained in the Filtering Request 
   should be applied with the sequence in which they appear in the 
   Filtering Request. Newly declared Filters should be associated with 
   the registered mobility binding. 
    
     
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   Binding management is performed with the help of the 'S' bit as 
   described in [1]. RFAs and GFAs receiving Filtering Requests 
   containing new Filter definitions or deletion requests are required 
   to handle them as Home Registrations [5] and forward them all the 
   way to the HA. In this manner it is assured that Filtering Agents 
   throughout the registration path maintain a consistent set of 
   Filters for a mobile node. In the case that an RFA or GFA receives a 
   Filtering Request with the purpose of transferring one or more known 
   Filters between two mobility bindings within its hierarchy then it 
   is required to handle it locally and issue a Filtering Reply. 
    
   A Filtering Reply contains one or more Filter Reply Extensions 
   indicating the Index of a Filter along with a Code signifying the 
   result of the respective Filtering Request. The Code is used to 
   relay success or the reason of rejection to the mobile node. If 
   routing optimization is supported then in the case of declined 
   Filters a Binding Acknowledgment with one or more Filter Reply 
   Extensions must be generated independently of whether the 'A' bit 
   was set in the Binding Update or not. 
    
   Successive updates to the Filters of a mobility binding may lead to 
   a mobility binding without any Filters. Such bindings remain idle 
   until either allocated a Filter, expire or deregistered by the 
   mobile node. A mobility binding in that state is termed as an Idle 
   Mobility Binding. When a Filtering Agent maintains exclusively Idle 
   Mobility Bindings for a mobile node then it is required to act as 
   per [1] and to ignore the behavior presented in this document. 
    
   A Filter remains valid for the lifetime of the corresponding 
   mobility binding. If the lifetime of a binding expires or it is 
   cancelled by the registration of another mobility binding then all 
   associated Filters are deleted from record. When renewing a mobility 
   binding a mobile node is not required to include any reference to 
   any requested Filters. If a mobile node wishes to reuse a deleted 
   Filter then it will have to be reissued with the corresponding 
   Filtering Request. 
    
   This document defines five different targets for Filters. These 
   represent different ways to handle flows that match a Filter. As 
   such, all packets of a flow(s) matching a Filter would either be 
   forwarded through the available tunnel or get rejected with or 
   without notification to their source. In addition, a mobile node may 
   request that it does not wish to receive routing optimization 
   services for specific flows. In that case, the Filtering Agent would 
   seize to issue Binding Update messages to CNs. Finally, the 
   Masquerading target option is used to perform remote private address 
   management. As such, one or more mobiles nodes would remain 
   reachable on a single globally routable address while roaming within 
   a private network. 
    
3.2 Model of Operation 
    
   The general model of operation is illustrated in figure 1. It shows 
   a mobile node that maintains multiple points of attachment in 
     
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   several visited domains. A visited domain may consist of several 
   different IP administrative domains (subnetworks). The extensions 
   presented do not provide any restriction as to how many points of 
   attachment a mobile node may maintain within a visited domain as 
   long as each point of attachment belongs to a different subnetwork. 
   When a mobile node registers an acquired point of attachment in the 
   home network then it is required to give up all other points of 
   attachment. 
    
   In figure 1, the mobile node has two separate points of attachment 
   in the Mobile IPv4 hierarchy of visited domain A. In addition, the 
   mobile node maintains two more points of attachment through visited 
   domains B and C. The mobile node maintains five incoming flows from 
   correspondent nodes CN1, CN2 and CN3. Flows associated with CN1 are 
   denoted with 'a' and 'b' while the respective flows for CN2 are 
   denoted with 'c' and 'd'. The flow associated with CN3 is denoted 
   with 'e'. 
    
   For communications with CN1, routing optimization has been assumed. 
   The mobile node maintains two simultaneous mobility bindings at the 
   GFA each associated with a Filter indicating that flows 'a' and 'b' 
   should be delivered to different points of attachment. The Filtering 
   Requests that established these mobility bindings and defined the 
   corresponding Filters where treated by the GRA as Home Registrations 
   and where forwarded to the HA. As such, the GFA as well as the HA 
   maintain a list of Filters requested by the mobile node. Their 
   difference is that the GFA maintains two separate simultaneous 
   mobility bindings with Filters for two different registered 
   (collocated)  care-of addresses while the HA maintains a single 
   mobility binding with two Filters, indicating the GFA as the 
   (collocated) care-of address. In this manner, Filter information is 
   kept in all Filtering Agents in the registration path but filtering 
   occurs at the most appropriate Filtering Agent. That is, flows 
   denoted with 'a' and 'b' are distributed between the available 
   points of attachment at the GFA, as this is the last common 
   Filtering Agent on their path to the mobile node. Similarly, flows 
   denoted with 'c' and 'd' that do not use routing optimization are 
   filtered at the HA and tunneled to different visited domains. In the 
   opposite manner, incoming flow 'e' from CN3 is terminated at the HA 
   as this the first Filtering Agent encountered in the path to the 
   mobile node and there is no need for that traffic to propagate 
   further into the network. This rejection of a flow can take place 
   either with or without notification to the sender on request by the 
   mobile node. 
    
   To return traffic a mobile node may choose any of the available 
   points of attachment. 
    
    
    
    
    
    
    
     
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              +---------------------+      +-------+                    
              |  Visited Domain  A  |      |  CN1  |                    
              |                     |      +-------+                    
              |                     |          |a                       
     a a a a a a +------+ a a a     |          |b                       
      -----------|  FA  |-----      |   +------|a-----+                 
    a|        |  +------+     |a        |      |b     |                 
     |        |           +-------+     |      |a     |                 
    a|        |           |  GFA  |------------ b     |                 
     |        |           +-------+ babababababa      |                 
    a|        |  +------+     |b    |   |             |                 
     |   --------|  FA  |-----      |   |             |                 
    a|  |b b b b +------+b b b b    |   |             |                 
     |  |     |                     |   |             |                 
    a|  |b    +---------------------+   |   Public    |   +-----------+ 
   +------+                             |   Network   |   |           | 
   |  MN  |   +---------------------+   |             |   |   Home    | 
   +------+   |  Visited Domain  B  |   |             |   |  Network  | 
     |d |c    |                     |   |             |   |           | 
     |  |  c c c +------+ c c c c c c c c c c c c c c c c c c c c c   | 
     |d  --------|  FA  |-----------------------------------------    | 
     |        |  +------+           |   |    d d d d d d d d d d  |c  | 
     |d       |                     |   |  d ------------------   |   | 
     |        |                     |   |   |         |   |    |d |c  | 
     |d       |                     |   |  d|   dcdcdcdcdcdc +------+ | 
     |        +---------------------+   |   |  c ------------|  HA  | | 
     |d                                 |  d|  d|     |   |  +------+ | 
     |        +---------------------+   +-- |--c|-----+   |     e|    | 
     |d       |                     |      d|  d|         +------|----+ 
     | d d d d d d d d d d d d d d d d d d  |  c|               e|      
      --------------------------------------   d|                |      
              |                     |          c|               e|      
              |  Visited Domain C   |       +-------+       +-------+   
              |                     |       |  CN2  |       |  CN3  |   
              +---------------------+       +-------+       +-------+   
    
   Figure 1: A mobile node with multiple points of attachment in 
             different visited domains. Incoming flows are redirected  
             by the respective Filtering Agents to a different care-of  
             address. In addition, mobile node chooses to have its HA  
             block flow 'e' . Blocking a flow may occur with or without  
             notification to the sender. 
    
    
4 Backwards compatibility with RFC3344 
    
   A domain that supports Filters for Mobile IPv4 Bindings should also 
   be backwards compatible. In Mobile IPv4, mobile nodes issue 
   registration requests without any Filters. Such registration 
   requests establish mobility bindings without Filters, considered in 
   this document as Idle Mobility Bindings. Such are mobility bindings 
   not in use, waiting to be allocated a Filter, expire or be 
   deregistered by a mobile node. In order to preserve backwards 
   compatibility with the basic protocol [1] it is stated in (section 
     
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   3.1) that a Filtering Agent maintaining only Idle Mobility Bindings 
   for a mobile is required to act as per [1] and to ignore the 
   behavior presented in this document. 
    
5 Associating Filters with Mobility Bindings 
    
   This section gives a detailed description of the steps taken by a 
   mobile node that wishes to associate Filters with its mobility 
   bindings. Furthermore, it is presented how a Filtering Agent reacts 
   to the receipt of a Filtering Request. 
    
5.1 Mobile Node Considerations 
    
   A mobile node that acquires a (collocated) care-of address within a 
   visited domain may issue a Filtering Request containing a list of 
   Filters. All included Filters will be associated with the registered 
   (collocated) care-of address at all Filtering Agents encountered on 
   the path to the HA. A mobile node that maintains multiple points of 
   attachment may request for simultaneous mobility bindings by setting 
   the 'S' bit on in its Filtering Requests. However, each of the 
   Filtering Requests must contain its own list of filters. Should the 
   Filtering Request be rejected then the mobile node will receive a 
   Filtering Reply with a Filter Reply Extension indicating the Index 
   of the Filter that was rejected along with the resulting for 
   rejection. If routing optimization is supported then a Binding 
   Acknowledgment with the failed Filters will be received 
   independently of whether the 'A' bit was set in the Binding Update. 
    
   It is important for a mobile node to keep a record of the Filters 
   and their corresponding Index numbers. 
    
   For the management of Filters six scenarios are identified. These 
   are presented along with the actions to be undertaken by the mobile 
   node. 
    
 Creating a new mobility binding with Filters 
    
   In order to create a new mobility binding with associated Filters 
   the mobile node must issue a Filtering Request including one or more 
   full Filter definitions (one or more Filter modules with Filter 
   Target Extension). Each of the Filters must be allocated a different 
   Index number. A higher Index indicates a Filter with a higher 
   priority. In the case of overlapping Filters, the one with the 
   highest Index is applicable. 
    
   The destination of the Filtering Request is identified as described 
   in [1] or [5]. If the mobile node already maintains a mobility 
   binding that it wishes to keep then it should set the 'S' bit in the 
   Filtering Request. 
    
 Replacing a Filter of a mobility binding by Index 
    
   In order for a mobile node to replace an existing Filter it is 
   required to issue a Filtering Request with a full definition of the 
     
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   new Filter. The Filter Target Extension of the Filter must indicate 
   the Index of the Filter to be replaced. The Target of the new Filter 
   may be different then the Target of the previous Filter definition. 
    
 Adding new Filters to an existing mobility binding 
    
   In order for a mobile node to add new Filters to an existing 
   mobility binding it is required to act as if creating a new mobility 
   binding with Filters. It is necessary for the new Filter to adopt an 
   unallocated Index number otherwise it would be replacing an existing 
   Filter with that Index. 
    
 Renewing a mobility binding with Filters 
    
   Periodically, a mobile node is required to renew its mobility 
   bindings in order to extend their lifetime. Renewing a mobility 
   binding may occur as described in [1] or [5]. Filtering Requests 
   with the purpose of renewing Filters and mobility binding are 
   required to include a Filter Control Extension indicating the mobile 
   nodeÆs intention to either renew all Filters or include a list of 
   Filter Indexes that need to be renewed. Filters associated with the 
   mobility binding whose Indexes are not included in the Filter 
   Control Extension will be automatically deleted. 
    
 Flushing all Filters or deleting a Filter from a mobility binding 
    
   In order for a mobile node to delete an existing Filter it is 
   required to issue a Filtering Request with one or more Filter 
   Control Extensions indicating the mobile nodeÆs intention to either 
   flush all Filters associated with the mobility binding or include a 
   list of Filter Indexes that need to be deleted. 
    
 Transferring a Filter between mobility bindings 
    
   In order for a mobile node to transfer an existing Filter between 
   two mobility bindings it is required to act as if creating a new 
   mobility binding with Filters and send out a Filtering Request from 
   the point of attachment to which it wants to have the Filter 
   transferred. The Filtering Request must contain the full Filter. 
   RFAs and GFAs receiving Filtering Requests with the aim of 
   transferring known Filters between mobility bindings must issue a 
   Filtering Reply and avoid forwarding to the HA. 
    
5.2 Filtering Agent Considerations 
    
   This section contains considerations for Filtering Agents. These are 
   Mobile IPv4 entities that can maintain mobility bindings such as 
   HA,s GFAs, RFAs or CNs when routing optimization is supported. 
    
   Filtering Agents that receive a Filtering Request containing one or 
   more previously unknown Filters are required to make a record of the 
   Filters and forward it to the next Filtering Agent until it reaches 
   the HA. In this manner it is ensured that all Filtering Agents in 
   the registration path maintain the same record of Filters for a 
     
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   mobile node. The address of the next Filtering Agent is determined 
   with the mechanisms described in [5]. 
    
   Upon receiving a Filtering Reply indicating that another Filtering 
   Agent has accepted the Filtering Request, Filtering Agents are 
   required to either establish a new mobility binding associated with 
   the corresponding Filters or update the one referred to by the 
   Filtering Request. Mobility binding management is performed with the 
   help of the 'S' bit as described in [1]. 
    
   Should the Filtering Agent fail to apply any of the Filters then for 
   each such Filter a Filter Reply Extension must be included in the 
   Filtering Reply indicating the Index of the rejected Filter along 
   with the reason of rejection. If authentication of the Filtering 
   Request fails then none of the Filters must be applied. 
    
   Filtering Agents that receive a Filtering Request containing one or 
   more Filter Control Extensions are required to renew, delete or set 
   a Default Filter as indicated by the Action field of the Filter 
   Control Extension and the list of Filter Indexes. If the Filtering 
   Agent does not maintain a record of any of the defined Filter 
   Indexes then it is required to ignore the Filter Control Extension, 
   flush all Filters for the mobile node and return a Filtering Request 
   with a Filter Reply Extension indicating an error message of UNKNOWN 
   FILTER (section 5.12). Filtering Agents receiving a Filtering Reply 
   containing a Filter Reply Extension with an error code of UNKNOWN 
   FILTER should flush all Filters for the mobile node and forward the 
   Filtering Reply. 
    
   When a Filtering Agent intercepts a packet for a mobile node for 
   which it maintains a mobility binding it is required to identify 
   whether the packet matches any of the Filters associated with the 
   mobility binding. If so, then the packet is handled as described by 
   the target of the corresponding Filter. If no matching Filter is 
   found then the packet is handled as indicated by the Default Filter. 
    
   When a mobility binding expires or is deregistered by a mobile node 
   then all associated Filters are deleted with it. Whenever a 
   Filtering Agent received a Filtering Request without any Filters 
   then it is required to establish an Idle Mobility Binding. If a 
   Filtering Agent maintains only Idle Mobility Bindings for a mobile 
   node then it is required to ignore the behavior described in this 
   document and to act as per [1]. 
    
 Home Agent Considerations 
    
   When an HA receives a Filtering Request that does not contain any 
   Filter declarations then it is required to process it as defined in 
   [1]. If the Filtering Request contains any Filter declarations then 
   these Filters must be associated with the registered (collocated) 
   care-of address. If these Filters can not be applied then the HA 
   must issue a Filtering Request including one or more Filter Reply 
   Extensions indicating the Index of the Filter that it failed to 
   apply along with the reason of rejection. 
     
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 Filters For Mobile IPv4 Bindings Registration Flag 
    
   The only change to the Mobility Agent Advertisement Extension 
   defined in [1] is a flag indicating that the HA supports Filters for 
   Mobile IPv4 Bindings. The flag is inserted after the flag defined in 
   [5]. 
    
      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      |    Length     |        Sequence Number        | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |           Lifetime            |R|B|H|F|M|G|V|T|S|I|N|reserved | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |     zero or more (collocated) care-of addresses               | 
      |                              ...                              | 
    
   The flag is defined as follows: 
    
        N   NOMADv4 Extension. This domain supports Filters for Mobile  
            IPv4 Bindings as specified in this document. 
    
Regional Registration Considerations 
    
 GFA/RFA Considerations 
 
   All Filtering Requests with the aim of defining, updating or 
   deleting Filters must be handled as Home Registrations and be 
   forwarded all the way to the HA. RFAs and GFAs receiving Filtering 
   Requests with the aim of transferring known Filters between mobility 
   bindings must issue a Filtering Reply and avoid forwarding to the 
   HA. 
    
    
6 NOMADv4 Extensions to RFC3344 Registration Messages 
    
   In this section the new Mobile IPv4 registration extensions required 
   for the support of Filters for Mobile IPv4 bindings are specified. 
    
   In NOMADv4, eleven types of registration extensions are defined. To 
   form a valid Filter, at least one of the extensions 1 to 9, termed 
   as Filter Modules, must be included. Extension 10 must appear once 
   in every Filter following all Filter Modules. Extension 11 is used 
   for Filter control and may appear more then once in a registration 
   request interleaving with Filter declarations. 
    
   Filter Modules of the same type may not appear in a Filter more than 
   once. A Filter Module may include one or more predicates. There is 
   an OR relationship between Filter Module predicates. That is, in 
   order for a flow to match a Filter Module it is required to qualify 
   for any of the predicates in it. In addition, there is an AND 
   relationship between Filter Modules of a Filter. As such, in order 
     
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   for a flow to match a Filter it is required to qualify for all its 
   Filter Modules.  
    
   All registration extensions defined in this document follow the 
   short extension format defined in [1]. In Filter Modules, the first 
   bit of the Sub-Type field is used to determine whether the rules 
   included in the Filter Module are positive or negative. In the first 
   case a flow is required to match exactly the predicates included in 
   the Filter Module while in the second the inverted (NOT) rule. 
    
   1. Behavior Aggregate Filters Extension (BAF) 
      Specifies to Filters data packets dependent of the content of the 
      DSCP field. 
    
   2. Protocol Extension 
      Specifies one or more protocols to be filtered. 
    
   3. Source Address Extension 
      Specifies one or more source adresses to be filtered. 
    
   4. Source Network Extension 
      Specifies one or more source networks (i.e. a interval of 
      IP addresses) to be filtered. 
    
   5. Source Port Extension 
      Specifies one or more source ports to be filtered. 
    
   6. Source Port Range Extension 
      Specifies one or more ranges of source ports to be filtered. 
    
   7. Destination Port Extension 
      Specifies one or more destination ports to be filtered. 
    
   8. Destination Port Range Extension 
      Specifies one or more ranges of destination ports to be filtered. 
    
   9. Free-Form Extension 
      It allows for the definition of complex Filters based on the 
      value of an area anywhere within a packet. The mobile node 
      is required to provide the packet offset, the qualifying 
      value as well as a mask. 
    
   10. Filter Target Extension 
       It contains a FilterÆs unique identifier, called the Index along  
       with the FilterÆs Target. 
    
   11. Filter Control Extension 
       It allows for the management of existing Filters. It contains a  
       list of Filter Indexes along and an indication of an action to  
       be taken on the respective Filters. 
    
   If a Filter contains a Protocol Extension with the Protocol field 
   set to the corresponding value for ICMP then the Filter may not 
   include any of the Filter Modules from 5-8 as they refer to sender 
     
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   and receiver port numbers that are not applicable for ICMP. Should a 
   Filtering Agent receive a Filtering Request with that configuration 
   of Filtering Modules, it is required to issue a Filtering Reply with 
   a Filter Control Extension indicating the FilterÆs Index and the 
   error code INVALID SYNTAX (section 5.12). 
    
6.1 Behavior Aggregate Filters (BAF) Extension 
    
      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      |    Length     |I|  Sub-Type   |    DSCP   |RSV| 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
         Type      The type, which describes a collection of extensions 
                   having a common data type. (To Be Defined). 
    
         Length    (N), where N is the number of DSCP entries 
    
         Sub-Type  0 for given predicates, 128 for inverted predicates. 
    
         I         Invert. A single bit at the end of the Sub-Type  
                   field used to invert predicates of Filter Module.  
                   Due to this bit two different Sub-Type values are  
                   given. 
    
         DSCP      Differentiated Services CodePoint 
    
   In Differentiated Services (DS) [7] the DS header field is defined 
   as a replacement for the IPv4 TOS [6] octets. Six bits of the DS 
   field are used as a codepoint (DSCP) to select the per-hop-behavior 
   that a packet receives at each node. For the purposes of NOMADv4 the 
   DSCP along with other header fields is used to construct Filters 
   that identify a specific flow or groups of them. 
    
   This Filter Module does not in any way alter or affect the DSCP 
   value of intercepted packets. 
    
6.2 Protocol Extension 
    
      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      |    Length     |I|  Sub-Type   |   Protocol    | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
         Type      The type, which describes a collection of extensions 
                   having a common data type. (To Be Defined). 
    
         Length    (N), where N is the number of Protocol fields 
    
         Sub-Type  1 for given predicates, 129 for inverted predicates 
    
         I (INVERT)A single bit at the end of the Sub-Type  
     
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                   field used to invert predicates of Filter Module.  
                   Due to this bit two different Sub-Type values are  
                   given. 
    
         Protocol  Identifies the next level protocol used in the data 
                   portion of the internet datagram. The values for  
                   various protocols are specified in [4]. 
    
6.3 Source Address Extension 
    
   The Source Address Extension is defined for IPv4 and IPv6. 
    
      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      |I|  Sub-Type   |             Length            | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                       Source IP Address                       | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
         Type      The type, which describes a collection of extensions 
                   having a common data type. (To Be Defined). 
    
         Length    (4*N), where N is the number of source IP address  
                   Fields. 
    
         Sub-Type  2 for given predicates, 130 for inverted predicates. 
    
         I         Invert. A single bit at the end of the Sub-Type  
                   field used to invert predicates of Filter Module.  
                   Due to this bit two different Sub-Type values are  
                   given. 
    
   Source IP Address 
                   Identifies the source IP address contained in the IP  
                   header of an incoming flow. 
    
6.4 Source Network Extension 
    
      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      |I|  Sub-Type   |             Length            | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                       Source IP Address                       | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                     Source IP Address Mask                    | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
         Type      The type, which describes a collection of extensions 
                   having a common data type. (To Be Defined). 
    
         Sub-Type  3 for given predicates, 131 for inverted predicates. 
    
     
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         I (INVERT)A single bit at the end of the Sub-Type  
                   field used to invert predicates of Filter Module.  
                   Due to this bit two different Sub-Type values are  
                   given. 
    
         Length   (8*N), where N is the number of pairs of a 
                   source IP address and a corresponding source 
                   IP address mask entry. 
    
   Source IP Address 
                   Identifies the base network IP address of a range of  
                   source IP addresses. 
    
   Source IP Address Mask 
                   Based on the source IP address field, identifies the  
                   range of source IP addresses. 
    
6.5 Source Port Extension 
    
      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      |I|  Sub-Type   |             Length            | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |          Source Port          | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
         Type      The type, which describes a collection of extensions 
                   having a common data type. (To Be Defined). 
    
         Sub-Type  4 for given predicates, 132 for inverted predicates. 
    
         I         Invert. A single bit at the end of the Sub-Type  
                   field used to invert predicates of Filter Module.  
                   Due to this bit two different Sub-Type values are  
                   given. 
    
         Length    (2*N), where N is the number of port entries. 
    
         Source Port 
                   Identifies the source port number contained in the 
                   IP header of an incoming flow. 
    
6.6 Source Port Range Extension  
    
      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      |I|  Sub-Type   |             Length            | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |        Source Port Min        |        Source Port Max        | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
         Type      The type, which describes a collection of extensions 
     
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                   having a common data type. (To Be Defined). 
    
         Sub-Type  5 for given predicates, 133 for inverted predicates. 
    
         I         Invert. A single bit at the end of the Sub-Type  
                   field used to invert predicates of Filter Module.  
                   Due to this bit two different Sub-Type values are  
                   given. 
    
         Length    (4*N), where N is the number of port range entries. 
    
         Source Port Number Min 
                   Defines the start point of a range of source port 
                   numbers. 
    
         Source Port Number Max 
                  Defines the end point of a range of source port  
                  Numbers. 
    
6.7 Destination Port Extension 
    
      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      |I|  Sub-Type   |             Length            | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |        Destination Port       | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
         Type      The type, which describes a collection of extensions 
                   having a common data type. (To Be Defined). 
    
         Sub-Type  6 for given predicates, 133 for inverted predicates. 
    
         I         Invert. A single bit at the end of the Sub-Type  
                   field used to invert predicates of Filter Module.  
                   Due to this bit two different Sub-Type values are  
                   given. 
    
         Length    (2*N), where N is the number of port entries 
    
         Destination Port 
                   Identifies the destination port number contained in  
                   the IP header of an incoming flow. 
    
6.8 Destination Port Range Extension  
    
      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      |I|  Sub-Type   |             Length            | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |     Destionation Port Min     |     Destionation Port Max     | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     
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         Type      The type, which describes a collection of extensions 
                   having a common data type. (To Be Defined). 
    
         Sub-Type  7 for given predicates, 134 for inverted predicates. 
    
         I         Invert. A single bit at the end of the Sub-Type  
                   field used to invert predicates of Filter Module.  
                   Due to this bit two different Sub-Type values are  
                   given. 
    
         Length    (4*N), where N is the number of port range entries 
    
         Destination Port Number Min 
                   Defines the start point of a range of destination  
                   port numbers 
    
         Destination Port Number Max 
                   Defines the end point of a range of destination port 
                   numbers 
    
6.9 Free-Form Extension 
    
      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      |I|  Sub-Type   |             Length            | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |             Offset            |              Value              
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
                                   .... 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                              Mask                               
                                   .... 
    
         Type      The type, which describes a collection of extensions 
                   having a common data type. (To Be Defined). 
    
         Sub-Type  7 for given predicates, 134 for inverted predicates. 
    
         I         Invert. A single bit at the end of the Sub-Type  
                   field used to invert predicates of Filter Module.  
                   Due to this bit two different Sub-Type values are  
                   given. 
    
         Length    Is variable, depends on the length of Value and  
                   Mask. 
    
         Offset    Indicates a location within a packet to be filtered 
                   in bytes. 
    
   The area indicated by the offset and for a length equivalent to that 
   of Mask is compared against Mask with the bitwise operator AND. The 
     
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   result of this operation is compared against Value. A match would 
   indicate that the packet qualifies the filter. 
    
   Value and Mask fields MUST have exactly the same size. However, this 
   size may vary with every free-form filter. For the sizes of Value 
   and Mask the following condition holds: 
    
   Value = Mask = (Length - 2) / 2 
    
6.10 Filter Target Extension 
    
      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      |    Sub-Type   |    Length     |     Target    | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |     Index     | 
     +-+-+-+-+-+-+-+-+ 
    
         Type      The type, which describes a collection of extensions 
                   having a common data type. (To Be Defined). 
    
         Sub-Type  125. 
    
         Length    2. 
    
         Target    Target of the filter 
    
         Index     FilterÆs index number 
    
   Admissible values for the Target field are as follows: 
         Value      FilterÆs Target 
         0          Reject incoming packets without notification 
         1          Reject incoming packets with notification 
         2          Accept incoming packets 
         3          Accept incoming packets but avoid route  
                    optimization 
         4          Masquerade 
    
6.11 Filter Control Extension 
    
      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      |    Sub-Type   |    Length     |     Action    | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |     Index     | 
     +-+-+-+-+-+-+-+-+ 
    
         Type      The type, which describes a collection of extensions 
                   having a common data type. (To Be Defined). 
    
         Sub-Type  126. 
    
     
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         Length    (N+1), where N is the number of Index entries 
    
         Action    Action to be undertaken to the listed Filter(s) 
    
         Index     A list of one or more FiltersÆ index numbers 
    
   Admissible values for the Action field are as follows: 
         Value      Filter Control Action 
         0          Delete Filter 
         1          Flush all Filters 
         2          Refresh Filter 
         3          Refresh all Filters 
         4          Make default Filter 
    
6.12 Filter Reply Extension 
    
      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      |    Sub-Type   |    Length     |      Code     | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |     Index     | 
     +-+-+-+-+-+-+-+-+ 
    
         Type      The type, which describes a collection of extensions 
                   having a common data type. (To Be Defined). 
    
         Sub-Type  127. 
    
         Length    2. 
    
         Index     A FilterÆs index number. 
    
    
Code Values for Filter Reply Extension 
    
   In this section the values to use within the Code field of the 
   Filter Control Extension are defined: 
    
   Successful Filtering Request Codes: 
    
         Code Name                Value   Section of Document 
         ----------------------   -----   ------------------- 
         REQUEST ACCEPTED         TBD 
    
   Failed Filtering Request Codes: 
    
         Error Name               Value   Section of Document 
         ----------------------   -----   ------------------- 
         TOO MANY FILTERS         TBD 
         INVALID FILTER SYNTAX    TBD 
         UNKNOWN FILTER           TBD 
         CAN NOT DROP MIP SIG     TBD 
    
     
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   The Error Code CAN NOT DROP MIP SIG is used when the mobile node 
   issues a Filtering Request requesting the drop of flows 
   corresponding to Mobile IPv4 signaling such as Agent Advertisements 
   or Registration Requests and Replies. 
    
    
7 Routing Optimization Extensions 
 
   Due to the lack of support for simultaneous bindings in routing 
   optimization for CNs requires the introduction of the 'S' bit to 
   binding update messages. 
    
7.1. Routing Optimization Extension for Simultaneous Bindings 
    
   The Binding Update message is defined in [3]. With this message it 
   is possible for a mobile node to establish a mobility binding at a 
   CN with routing optimization support. However, with every subsequent 
   Binding Update the CN is required to cancel the older mobility 
   binding and to establish a new one. In order to enable simultaneous 
   binding support the 'S' bit is introduced in the Binding Update 
   message. 
    
      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      |A|I|M|G|S| Rsv |            Lifetime           | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                    Mobile Node Home Address                   | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                       care-of address                         | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                                                               | 
     +                         Identification                        + 
     |                                                               | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     | Extensions ... 
     +-+-+-+-+-+-+-+- 
    
         S         Simultaneous bindings. If the 'S' bit is set on, the  
                   mobile node is requesting that the correspondent  
                   node retains its prior mobility bindings. 
    
   All other fields are defined in [3]. 
    
    
8 Intellectual Property Considerations 
    
   This proposal is in full conformity with [9]. 
    
   Siemens may have patent rights on technology described in this 
   document which employees of Siemens contribute for use in IETF 
   standard discussions. In relation to any IETF standard incorporating 
   any such technology, Siemens hereby agrees to license on fair, 
   reasonable and non-discriminatory terms, based on reciprocity, any 
     
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   patent claims it owns covering such technology, to the extent such 
   technology is essential to comply with such standard. 
    
    
9 Acknowledgements 
    
   The editor of this document would like to thank Mrs. Koojana 
   Kuladinithi for her precious input to this version of the draft. In 
   addition, the authors would like to thank all reviewers for their 
   help. 
    
    
References 
    
[1]     C. Perkins. IP Mobility Support. RFC (Proposed Standard) 3344,  
        IETF, August 2002. 
[2]     S. Bradner. Key words for use in RFCs to Indicate Requirement  
        Levels. RFC 2119, IETF, March 1997. 
[3]     C. Perkins and D. Johnson. Route Optimization in Mobile IP. 
        (work in progress). draft-ietf-mobileip-optim-11.txt, 
        IETF, September 2001. (expired; not updated) 
[4]     J. Reynolds and J. Postel. Assigned Numbers. Request for 
        Comments 1700, STD 2, IETF, October 1994. 
[5]     E. Gustafsson, A. Jonsson and C. Perkins. Mobile IP Regional  
        Registration. (work in progress). 
        draft-ietf-mobileip-reg-tunnel-07.txt, IETF, October 2002. 
[6]     Postel, J. Internet Protocol. STD 5, RFC 791, IETF, 
        September 1981. 
[7]     K. Nichols, S. Blake, F. Baker, and D. Black. Definition of 
        the Differentiated Services Field (DS Field) in the IPv4 and 
        IPv6 Headers. RFC 2474, IETF, December 1998. 
[8]     S. Deering and R. Hinden, Internet Protocol, Version 6 (IPv6)  
        Specification. RFC 2460, IETF, December 1998. 
[9]     S. Brander. The Internet Standards Process -- Revision 3. RFC  
        2026, IETF, October 1996 
 
 
A. Changes from Previous Versions 
    
   The following updates and changes were made in this version of the 
   Filters for Mobile IPv4 Bindings draft, compared to earlier 
   versions. 
    
   A.1. Updates from version 02 
    
   Version 3 is almost a complete rewrite of version 2, based on 
   experience acquired from the implementation of version 2. 
    
   Renamed Binding Agents to Filter Agents and Binding Requests & 
   Replies to Filtering Requests & Replies. 
     
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   Defined in section 3.2 Model of operation that a mobile node may not 
   maintain more then one points of attachment in a single subnetwork. 
   Should the mobile node acquire one point of attachment in the home 
   network then all other must be given up. 
    
   Defined in section 3.1 Protocol Description and in the beginning of 
   section 5 NOMADv4 Extensions to RFC3344 Registration Messages the 
   structure of a Filter and the relation between Filter Module 
   predicates, Filter Modules and Filters. In addition, the Filter 
   Control Extension was renamed as Filter Target Extension while a new 
   extension by the name Filter Control Extension was defined. Removed 
   Action field from Filter Target Extension and increased Target and 
   Index fields to occupy 8 bits. 
    
   Removed P and A bits from Free Form Filter. 
    
   Added section 4 Backwards compatibility with RFC3344 
    
   Extended section on Mobile Node Considerations and Filtering Agent 
   Considerations in section 5 Associating Filters with Mobility 
   Bindings. Described specific actions undertaken by mobile node. 
    
   Renamed Default Binding to Default Filter and redefined it. Now 
   Fitlerless mobility bindings may not be Default Bindings. 
    
   Clarified that Index number denotes priority. 0 is lowest priority. 
   Index 0 is reserved for Default Filter. 
    
   Introduced the Filter Reply Extension for the relay of success and 
   error codes from Filtering Agents to mobile nodes. Defined success 
   and error codes. 
    
   Included INVERT flag in Filter Modules. 
    
   Introduced destination port and destination port range Filter 
   Modules. 
    
   Remove all reference to Filters for Mobile Ipv6 bindings as this be 
   the purpose of a separate Internet draft. 
    
    
Authors' Addresses 
    
   Niko A. Fikouras 
   Department of Communication Networks (ComNets) 
   Center for Information and Communication Technology (ikom) 
   University of Bremen         Phone:  +49-421-218-3339 
   D-28219 Bremen, Germany      Email:  niko@comnets.uni-bremen.de 
    
   Asanga Udugama 
   Department of Communication Networks (ComNets) 
   Center for Information and Communication Technology (ikom) 
   University of Bremen         Phone:  +49-421-218-8665 
     
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   Internet Draft     Filters for Mobile IPv4 Bindings      April 2003 
    
   D-28219 Bremen, Germany      Email:  adu@comnets.uni-bremen.de 
    
   Andreas J. Koensgen 
   Department of Communication Networks (ComNets) 
   Center for Information and Communication Technology (ikom) 
   University of Bremen         Phone:  +49-421-218-3339 
   D-28219 Bremen, Germany      Email:  ajk@comnets.uni-bremen.de 
    
   Carmelita Goerg 
   Department of Communication Networks (ComNets) 
   Center for Information and Communication Technology (ikom) 
   University of Bremen         Phone:  +49-421-218-2277 
   28219, Bremen, Germany       Email:  cg@comnets.uni-bremen.de 
    
   Wolfgang Zirwas 
   Siemens AG 
   ICM N MR-ST 8 
   Werner-von-Siemens Ring 20 
   D-85630 Grasbrunn            Phone:  +49-89-722-34369 
   Germany                      Email:  wolfgang.zirwas@icn.siemens.de 
    
   Josef Martin Eichinger 
   Siemens AG 
   ICM N PG SP RC FR 
   Gustav-Heinemann Ring 11 
   D-81730 M’nchen              Phone:  +49-89-636 44838 
   Germany                      Email:  josef-m.eichinger@siemens.com 
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
     
   NOMADv4               Expires October 2003                       25 

PAFTECH AB 2003-20262026-04-22 23:21:29