]> CEA, LIST

Communicating Systems Laboratory, Point Courrier 173 Gif-sur-Yvette F-91191 France +33 169083976 michael.boc@cea.fr

CEA, LIST

Communicating Systems Laboratory, Point Courrier 173 Gif-sur-Yvette F-91191 France +33 (0) 169089182 christophe.janneteau@cea.fr

CEA, LIST

Communicating Systems Laboratory, Point Courrier 173 Gif-sur-Yvette F-91191 France +33 (0) 169089223 alexandru.petrescu@cea.fr

The communication path between two Hosts within a Proxy Mobile IPv6 domain is artificially long - it involves the LMA, even if straight paths exist (under same MAG, or MAG-to-MAG). Localized Routing PMIPv6-LR concepts developped by NETEXT WG make use of LRI/LRA messages to achieve optimized MAG-to-MAG straight paths. This may prove inconvenient for the network operator, in that it may loose ability to control traffic (LMA control point is skipped). In this draft we present a middle-ground solution. It employs new Intermediary Anchors (IAs) in the paths between MAGs and offers points of control of traffic useful for QoS and lawful interception.

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 .

The work presented in this draft is developped in the context of Proxy Mobile IPv6 and uses LRI/LRA messages used by Localized Routing . The relevant scenarios are represented by communication between two Hosts typically situated each under a different MAG.

In this figure, on the left side, the established tunnels T1 and T2 for communication between Host1 and Host2 are shown, after the Proxy Mobile IPv6 protocol has executed. Each tunnel is established between LMA and the MAG under which a Host is attached. This illustration is typically used to express a problem of too long communication paths. In the right part of the same figure, the Direct Tunnel between two MAGs is illustrated as a solution to the problem of artificially long paths through LMA. This is achieved by using Localized Routing concepts of Proxy Mobile IPv6. The diagonal lines represent signalling (not wires). There may exist situations when MAG-LMA-MAG communication paths are too long and yet the straight MAG-MAG paths may prove disadvantageous in terms of loss of operator control on various aspects of the traffic. A middle ground solution as a bent arch path (not fully triangular, not fully straight) may be needed.

In this figure a new entity is added between MAGs - the Intermediate Anchor (IA). The tunnels T1 and T2 are established between the IA and the two MAGs respectively (instead of LMA). The IA serves purposes such as ensuring a certain level of control over the route optimized traffic, such as providing a certain level of Quality-of-Service, or, potentially, enabling data traffic enforcement for lawful interception. Several such IAs may be placed at strategic points within the Proxy Mobile IPv6 domain. The LMA is pre-configured statically with information about the IP addresses of all MAGs, and, new, IAs in the Proxy Mobile IPv6 domain. To illustrate this procedure in a generic manner, we consider two IAs instead of one. In the following figure, we assume that IA1 and IA2 are positioned in a "sequential" manner between the MAG1 and MAG2. This is to illustrate that the mechanism pertains to situations where more IAs are used, and not only one. Initially, H1 and H2 exchange Data through the tunnels setup by Proxy Mobile IPv6, via LMA and the respective MAGs (the first 4 double-arrowed lines at the top of the illustration) .

| | | | Data | | | |<--------------------------------->| | | | | | | Data | via LMA | | | Data |<----------------------->| and MAG | |<----------------->| | | | | | | | | | | | | |[Trigger RO procedure] |LRI_IA1 | | | | | |<---------------| | | | | |LRA_IA1| | | | | | |--------------->| | | | | | |LRI_IA2 | RO | | | | | |<-------| configure | | | | | |LRA_IA2 | | | | | | |------->| | | | LRI_MAG1 | | | | | |<--------------------------------- | | | | LRA_MAG1 | | | | | |---------------------------------->| | | | | LRI_MAG2 | | | | | |<------------------------| | | | | LRA_MAG2 | | | | | |------------------------>| | Data | | | | | |<---------------->| Data | | | | | | |<---------------->| | | | | | | | Data | | | | | | |<----->| | | | | | Data | | | via IA | | | |<-------------->| | and MAG | | Data | | | | | | |<----------------->| | | | ]]>

Subsequently, a certain trigger (to be defined) starts the Route Optimization procedure. The procedure consists in LRI and LRA messages. The LMA sends an LRI to IA1 and to IA2 respectively. In a same centralized manner, LMA sends the same type of messages to MAG1 and MAG2 respectively. There are as many LRI messages as there are IAs plus (always) two MAGs. The LRI messages instruct the receivers about the IP addresses of the entities in question. For example, LRI_IA1 informs IA1 about the IP address of IA2. When the last LRA has been received from a second MAG, it can be considered that the paths have been "route optimized", i.e. LMA is no longer in the path. The Data traffic between H1 and H2 is exchanged via IAs and MAGs exclusively (LMA is skipped). The following diagram shows a modified LRI message.

'I' flag: if set to 1 it indicates that this message is for an Intermediate Anchor. The following diagram shows a modified LRA message.

'I' flag: if set to 1 it indicates that this message is is sent by an Intermediate Anchor.

LMA is pre-configured with each address of each MAG and of each IA in the Proxy Mobile IPv6 domain. In addition, it has topology information about the placement of these entities (IA, MAG) with respect to each other, and can know the IP distances (hopcount) between each to each other. For example, for two given MAGs, it knows the shortest path and the IP addresses of the intervening IAs. LMA is expecting a trigger indicating that the Route Optimization procedure should start. This trigger is to be defined. In one sense, LMA could deduce this trigger when its Binding Cache is updated. Speculatively, the addresses stored in the Binding Cache could indicate that two Hosts are under MAGs of same LMA, and that their tunnels are using LMA. The LMA emits LRI messages and, for each LRI sent it waits for an LRA. It sends the following LRI only when the preceding LRI has been arcknowledged by an LRA.

MAG receives LRI messages, and does not generate such. When LRI is received, it executes indications contained in it. Upon completion, it sends LRA to the originator of the LRI (the LMA) explaining the success or error of execution. MAG does not receive LRA.

IA behaviour is similar to that of MAG.

Lawful interception is probably the single most unique kind of requirement difficult to fit within the otherwise very powerful security architecture of Internet. It is not immediately obvious whether techniques addressing this particular requirement effectively influence or are influenced by Internet security. LRI and LRA messages should be protected by using IPsec.

Other than Authors, a number of persons are involved with implementation and protection of this technique. For example, Sofiane Imadali is designing and implementing a testbed prototype with C, linux and Ethernet, under wise guidance of advisor. Administratively, this work has been performed in the framework of CELTIC project CP7-011 MEVICO. The authors would like to acknowledge the contributions of their colleagues, although the views expressed are those of the authors and do not necessarily represent the project.

&rfc2119;

The changes are listed in reverse chronological order, most recent changes appearing at the top of the list. From draft-boc-netext-lr-roext-03.txt to draft-boc-netext-lr-roext-04.txt: Date change, no content change. From draft-boc-netext-lr-roext-01.txt to draft-boc-netext-lr-roext-02.txt: Changed affiliation from "CEA LIST" to "CEA, LIST" to respect local guidelines. From draft-boc-netext-lr-roext-00.txt to draft-boc-netext-lr-roext-01.txt: The -00 version was mostly a placeholder. Now with -01 we updated the message exchange diagram and added its respective explanatory text. Added new sections intended to describe behaviour per entity (LMA, IA, MAG).