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Is this intentional? -- Found something which looks like a code comment -- if you have code sections in the document, please surround them with '' and '' lines. Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-26) exists of draft-ietf-p2psip-base-19 == Outdated reference: A later version (-09) exists of draft-ietf-p2psip-concepts-04 Summary: 0 errors (**), 0 flaws (~~), 4 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 P2PSIP Working Group J. Maenpaa 3 Internet-Draft G. Camarillo 4 Intended status: Standards Track Ericsson 5 Expires: July 9, 2012 January 6, 2012 7 Service Discovery Usage for REsource LOcation And Discovery (RELOAD) 8 draft-ietf-p2psip-service-discovery-04.txt 10 Abstract 12 REsource LOcation and Discovery (RELOAD) does not define a generic 13 service discovery mechanism as part of the base protocol. This 14 document defines how the Recursive Distributed Rendezvous (ReDiR) 15 service discovery mechanism used in OpenDHT can be applied to RELOAD 16 overlays to provide a generic service discovery mechanism. 18 Status of this Memo 20 This Internet-Draft is submitted to IETF in full conformance with the 21 provisions of BCP 78 and BCP 79. 23 Internet-Drafts are working documents of the Internet Engineering 24 Task Force (IETF). Note that other groups may also distribute 25 working documents as Internet-Drafts. The list of current Internet- 26 Drafts is at http://datatracker.ietf.org/drafts/current/. 28 Internet-Drafts are draft documents valid for a maximum of six months 29 and may be updated, replaced, or obsoleted by other documents at any 30 time. It is inappropriate to use Internet-Drafts as reference 31 material or to cite them other than as "work in progress." 33 This Internet-Draft will expire on July 9, 2012. 35 Copyright Notice 37 Copyright (c) 2012 IETF Trust and the persons identified as the 38 document authors. All rights reserved. 40 This document is subject to BCP 78 and the IETF Trust's Legal 41 Provisions Relating to IETF Documents 42 (http://trustee.ietf.org/license-info) in effect on the date of 43 publication of this document. Please review these documents 44 carefully, as they describe your rights and restrictions with respect 45 to this document. Code Components extracted from this document must 46 include Simplified BSD License text as described in Section 4.e of 47 the Trust Legal Provisions and are provided without warranty as 48 described in the Simplified BSD License. 50 Table of Contents 52 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 53 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 54 3. Introduction to ReDiR . . . . . . . . . . . . . . . . . . . . 4 55 4. Using ReDiR in a RELOAD Overlay Instance . . . . . . . . . . . 6 56 4.1. Data Structure . . . . . . . . . . . . . . . . . . . . . . 6 57 4.2. Selecting the Starting Level . . . . . . . . . . . . . . . 7 58 4.3. Service Provider Registration . . . . . . . . . . . . . . 7 59 4.4. Refreshing Registrations . . . . . . . . . . . . . . . . . 8 60 4.5. Service Lookups . . . . . . . . . . . . . . . . . . . . . 8 61 4.6. Removing Registrations . . . . . . . . . . . . . . . . . . 9 62 5. Access Control Rules . . . . . . . . . . . . . . . . . . . . . 9 63 6. REDIR Kind Definition . . . . . . . . . . . . . . . . . . . . 10 64 7. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 65 8. Overlay Configuration Document Extension . . . . . . . . . . . 12 66 9. Security Considerations . . . . . . . . . . . . . . . . . . . 12 67 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 68 10.1. Access Control Policies . . . . . . . . . . . . . . . . . 13 69 10.2. Data Kind-ID . . . . . . . . . . . . . . . . . . . . . . . 13 70 10.3. ReDiR Namespaces . . . . . . . . . . . . . . . . . . . . . 13 71 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 72 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 73 12.1. Normative References . . . . . . . . . . . . . . . . . . . 14 74 12.2. Informative References . . . . . . . . . . . . . . . . . . 14 75 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 77 1. Introduction 79 REsource LOcation And Discovery (RELOAD) [I-D.ietf-p2psip-base] is a 80 peer-to-peer signaling protocol that can be used to maintain an 81 overlay network, and to store data in and retrieve data from the 82 overlay. Although RELOAD defines a Traversal Using Relays around 83 Network Address Translation (TURN) specific service discovery 84 mechanism, it does not define a generic service discovery mechanism 85 as part of the base protocol. This document defines how the 86 Recursive Distributed Rendezvous (ReDiR) service discovery mechanism 87 [Redir] used in OpenDHT can be applied to RELOAD overlays. 89 In a Peer-to-Peer (P2P) overlay network such as a RELOAD Overlay 90 Instance, the peers forming the overlay share their resources in 91 order to provide the service the system has been designed to provide. 92 The peers in the overlay both provide services to other peers and 93 request services from other peers. Examples of possible services 94 peers in a RELOAD Overlay Instance can offer to each other include a 95 TURN relay service, a voice mail service, a gateway location service, 96 and a transcoding service. Typically, only a small subset of the 97 peers participating in the system are providers of a given service. 98 A peer that wishes to use a particular service faces the problem of 99 finding peers that are providing that service from the Overlay 100 Instance. 102 A naive way to perform service discovery is to store the Node-IDs of 103 all nodes providing a particular service under a well-known key k. 104 The limitation of this approach is that it scales linearly in the 105 number of nodes that provide the service. The problem is two-fold: 106 the node n that is responsible for service s identified by key k may 107 end up storing a large number of Node-IDs and most importantly, may 108 also become overloaded since all service lookup requests for service 109 s will need to be answered by node n. An efficient service discovery 110 mechanism does not overload the nodes storing pointers to service 111 providers. In addition, the mechanism must ensure that the load of 112 providing a given service is distributed evenly among the nodes 113 providing the service. 115 ReDiR implements service discovery by building a tree structure of 116 the nodes that provide a particular service and embedding it into the 117 RELOAD Overlay Instance using RELOAD Store and Fetch requests. Each 118 service provided in the Overlay Instance has its own tree. The nodes 119 in a ReDiR tree contain pointers to service providers. During 120 service discovery, a peer wishing to use a given service fetches 121 ReDiR tree nodes one-by-one from the RELOAD Overlay Instance until it 122 finds a service provider responsible for its Node-ID. It has been 123 proved that ReDiR can find a service provider using only a constant 124 number of Fetch operations [Redir]. 126 2. Terminology 128 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 129 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 130 document are to be interpreted as described in RFC 2119 [RFC2119]. 132 This document uses the terminology and definitions from the Concepts 133 and Terminology for Peer to Peer SIP [I-D.ietf-p2psip-concepts] 134 draft. 136 DHT: Distributed Hash Tables (DHTs) are a class of decentralized 137 distributed systems that provide a lookup service similar to a 138 hash table. Given a key, any participating peer can retrieve the 139 value associated with that key. The responsibility for 140 maintaining the mapping from keys to values is distributed among 141 the peers. 143 H(x): Hash calculated over x. 145 I(l,k): The unique interval at level l in the ReDiR tree that 146 encloses key k. 148 n.id: Node-ID of node n. 150 Namespace: An arbitrary identifier that identifies a service 151 provided in the RELOAD Overlay Instance. An example of a 152 namespace is "voice-mail". The namespace is an UTF-8 text string. 154 numBitsInNodeId: Number of bits in a Node-ID. 156 ReDiR tree: A tree structure of the nodes that provide a particular 157 service. The nodes embed the ReDiR tree into the RELOAD Overlay 158 Instance using RELOAD Store and Fetch requests. 160 Successor: The successor of identifier k in namespace ns is the node 161 that has joined ns whose identifier most immediately follows k. 163 3. Introduction to ReDiR 165 Recursive Distributed Rendezvous (ReDiR) [Redir] does not require new 166 functionality from the RELOAD base protocol. This is possible since 167 ReDiR interacts with the RELOAD overlay through a put/get API using 168 RELOAD Store and Fetch requests. ReDiR builds a tree structure of 169 the nodes that provide a particular service and embeds it into the 170 RELOAD Overlay Instance using the Store and Fetch requests. ReDiR 171 performs lookup in a logarithmic number of Fetch operations with high 172 probability. Further, if the tree's height is estimated based on 173 past lookups, the average lookup can be reduced to a constant number 174 of Fetch operations assuming that Node-IDs are distributed uniformly 175 at random. 177 In ReDiR, each service provided in the overlay is identified by an 178 arbitrary identifier, called its namespace. All service providers 179 join a namespace and peers wishing to use a service perform lookups 180 within the namespace of the service. A ReDiR lookup for identifier k 181 in namespace ns returns a node that has joined ns whose identifier is 182 the closest successor of k. 184 Each tree node in the ReDiR tree contains a list of Node-IDs of peers 185 providing a particular service. Each node in the tree has a level. 186 The root is at level 0, the immediate children of the root are at 187 level 1, and so forth. The ReDiR tree has a branching factor, whose 188 value is determined by a new element in the RELOAD overlay 189 configuration document, called branching-factor. At every level i in 190 the tree, there are at most branching-factor^i nodes. The nodes at 191 any level are labeled from left to right, such that a pair (i,j) 192 uniquely identifies the jth node from the left at level i. This tree 193 is embedded into the RELOAD Overlay Instance node by node, by storing 194 the values of node (i,j) at key H(namespace,i,j). As an example, the 195 root of the tree for a voice mail service is stored at H("voice- 196 mail",0,0). Each node (i,j) in the tree is associated with 197 branching-factor intervals of the DHT keyspace as follows: 199 [2^numBitsInNodeID*b^(-i)*(j+(b'/b)), 200 2^numBitsInNodeID*b^(-i)*(j+((b'+1)/b))), for 0<=b'; 241 uint16 level; 242 uint16 node; 243 uint16 length; 245 select (type) { 246 /* This type may be extended */ 247 } extension; 249 } RedirServiceProvider; 251 The contents of the RedirServiceProvider Resource Record are as 252 follows: 254 type 255 The type of an extension to the RedirServiceProvider Resource 256 Record. Unknown types are allowed. 258 serviceProvider 259 The Node-ID of a service provider. 261 namespace 262 An opaque string containing the namespace. 264 level 265 The level in the ReDiR tree. 267 node 268 The position of the node storing this RedirServiceProvider record 269 at the current level in the ReDiR tree. 271 length 272 The length of the rest of the Resource Record. 274 extension 275 An extension value. The RedirServiceProvider Resource Record can 276 be extended to include for instance service or service provider 277 specific information. 279 4.2. Selecting the Starting Level 281 Before registering as a service provider or performing a service 282 lookup, a peer needs to determine the starting level Lstart for the 283 registration or lookup operation in the ReDiR tree. It is 284 RECOMMENDED that Lstart is initially set to 2. In subsequent 285 registrations, Lstart MUST be set to the lowest level at which 286 registration last completed. 288 In the case of service lookups, nodes MUST record the levels at which 289 the last 16 service lookups completed and take Lstart to be the mode 290 of those depths. 292 4.3. Service Provider Registration 294 A node MUST use the following procedure to register as a service 295 provider in the RELOAD Overlay Instance: 297 1. A node n with Node-ID n.id wishing to register as a service 298 provider starts from level Lstart (see Section 4.2 for the 299 details on selecting the starting level). Therefore, node n sets 300 level=Lstart. 302 2. Node n MUST send a RELOAD Fetch request to fetch the contents of 303 the tree node associated with I(level,n.id). An interval I(l,k) 304 is defined as the unique interval at level l in the ReDiR tree 305 that encloses key k. The fetch MUST be a wildcard fetch. 306 3. Node n MUST send a RELOAD Store request to add its 307 RedirServiceProvider entry to the dictionary stored in the tree 308 node associated with I(level,n.id) 309 4. If node n's Node-ID is the numerically lowest or highest among 310 the Node-IDs stored in the tree node associated with 311 I(Lstart,n.id), node n MUST continue up the tree towards the root 312 (level 0), repeating steps 2 and 3. Node n MUST continue this 313 until it reaches either the root or a level at which n.id is not 314 the lowest or highest Node-ID in the interval I(level,n.id). 315 5. Node n MUST also walk down the tree through tree nodes associated 316 with the intervals I(Lstart,n.id),I(Lstart+1,n.id),..., at each 317 step fetching the current contents of the tree node, and storing 318 its RedirServiceProvider record if n.id is the lowest or highest 319 Node-ID in the interval. Node n MUST end this downward walk when 320 it reaches a level at which it is the only service provider in 321 the interval. 323 Note that above, when we refer to 'the tree node associated with 324 I(l,k)', we mean the entire tree node (that is, all the intervals 325 within the tree node) responsible for interval I(l,k). In contrast, 326 I(l,k) refers to a specific interval within a tree node. 328 4.4. Refreshing Registrations 330 All state in the ReDiR tree is soft. Therefore, a service provider 331 needs to periodically repeat the registration process to refresh its 332 RedirServiceProvider Resource Record. If a record expires, it MUST 333 be dropped from the dictionary by the peer storing the tree node. 334 Deciding an appropriate lifetime for the RedirServiceProvider 335 Resource Records is up to each service provider. Every service 336 provider MUST repeat the entire registration process periodically 337 until it leaves the RELOAD Overlay Instance. 339 Note that no new mechanisms are needed to keep track of the remaining 340 lifetime of RedirServiceProvider records. The 'storage_time' and 341 'lifetime' fields of RELOAD's StoredData structure can be used for 342 this purpose in the usual way. 344 4.5. Service Lookups 346 The purpose of a service lookup on identifier k in namespace ns is to 347 find the node that has joined ns whose identifier most immediately 348 follows identifier k. 350 A service lookup is similar to the registration operation. The 351 service lookup starts from some level level=Lstart (see Section 4.2 352 for the details on selecting the starting level). At each step, the 353 node n wishing to discover a service provider MUST fetch the tree 354 node associated with the current interval I(level,n.id) using a 355 RELOAD Fetch request and MUST determine where to look next as 356 follows: 358 1. If the successor of node n is not present in the tree node 359 associated with I(level,n.id), then its successor must occur in a 360 larger range of the keyspace. Node n MUST set level=level-1 and 361 try again. 362 2. If n.id is sandwiched between two Node-IDs in I(level,n.id), the 363 successor must lie somewhere in I(level,n.id). Node n MUST set 364 level=level+1 and repeat. 365 3. Otherwise, there is a Node-ID s stored in the node associated 366 with I(level,n.id) whose identifier succeeds n.id, and there are 367 no Node-IDs between n.id and s. Thus, s must be the closest 368 successor of n.id, and the lookup is done. 370 Note that above, when we refer to 'the tree node associated with 371 I(l,k)', we mean the entire tree node (that is, all the intervals 372 within the tree node) responsible for interval I(l,k). In contrast, 373 I(l,k) refers to a specific interval within a tree node. 375 4.6. Removing Registrations 377 Before leaving the RELOAD Overlay Instance, a service provider MUST 378 remove the RedirServiceProvider records it has stored by storing 379 exists=False values in their place, as described in 380 [I-D.ietf-p2psip-base]. 382 5. Access Control Rules 384 As specified in RELOAD base [I-D.ietf-p2psip-base], every kind which 385 is storable in an overlay must be associated with an access control 386 policy. This policy defines whether a request from a given node to 387 operate on a given value should succeed or fail. Usages can define 388 any access control rules they choose, including publicly writable 389 values. 391 ReDiR requires an access control policy that allows multiple nodes in 392 the overlay read and write access to the ReDiR tree nodes stored in 393 the overlay. Therefore, none of the access control policies 394 specified in RELOAD base [I-D.ietf-p2psip-base] is sufficient. 396 This document defines a new access control policy, called NODE-ID- 397 MATCH. In this policy, a given value MUST be written and overwritten 398 only if the the request is signed with a key associated with a 399 certificate whose Node-ID is equal to the dictionary key. In 400 addition, provided that exists=TRUE, the Node-ID MUST belong to one 401 of the intervals associated with the tree node (the number of 402 intervals each tree node has is determined by the branching-factor 403 parameter). Finally, provided that exists=TRUE, 404 H(namespace,level,node), where namespace, level, and node are taken 405 from the RedirServiceProvider structure being stored, MUST be equal 406 to the Resource-ID for the resource. The NODE-ID-MATCH policy may 407 only be used with dictionary types. 409 6. REDIR Kind Definition 411 This section defines the REDIR kind. 413 Name 414 REDIR 416 Kind IDs 417 The Resource Name for the REDIR Kind-ID is created by 418 concatenating three pieces of information: namespace, level, and 419 node number. Namespace is a string identifying a service, such as 420 "voice-mail". Level is an integer specifying a level in the ReDiR 421 tree. Node number is an integer identifying a ReDiR tree node at 422 a specific level. The data stored is a RedirServiceProvider 423 structure that was defined in Section 4.1. 425 Data Model 426 The data model for the REDIR Kind-ID is dictionary. The 427 dictionary key is the Node-ID of the service provider. 429 Access Control 430 The access control policy for the REDIR kind is the NODE-ID-MATCH 431 policy that was defined in Section 5. 433 7. Example 435 Figure 2 shows an example of a ReDiR tree containing information 436 about four different service providers whose Node-IDs are 2, 3, 4, 437 and 7. In the example, numBitsInNodeID=4. Initially, the ReDiR tree 438 is empty. 440 Level 0 ____2_3___4_____7_|__________________ 441 | | 442 Level 1 ____2_3_|_4_____7 ________|________ 443 | | | | 444 Level 2 ___|2_3 4__|__7 ___|___ ___|___ 445 | | | | | | | | 446 Level 3 _|_ _|3 _|_ _|_ _|_ _|_ _|_ _|_ 448 Figure 2: Example of a ReDiR tree 450 First, peer 2 whose Node-ID is 2 joins the namespace. Since this is 451 the first registration peer 2 performs, peer 2 sets the starting 452 level Lstart to 2, as was described in Section 4.2. Also all other 453 peers in this example will start from level 2. First, peer 2 fetches 454 the contents of the tree node associated with interval I(2,2) from 455 the overlay. Peer 2 also stores its RedirServiceProvider record in 456 that tree node. Since peer 2's Node-ID is the only Node-ID stored in 457 the tree node (i.e., peer 2's Node-ID fulfills the condition that it 458 is the numerically lowest or highest among the keys stored in the 459 node), peer 2 continues up the tree. In fact, peer 2 continues up in 460 the tree all the way to the root inserting its own Node-ID in all 461 levels since the tree is empty (which means that peer 2's Node-ID 462 always fulfills the condition that it is the numerically lowest or 463 highest Node-ID in the interval I(level, 2) during the upward walk). 464 As described in Section 4.3, peer 2 also walks down the tree. The 465 downward walk peer 2 does ends at level 2 since peer 2 is the only 466 node in its interval at that level. 468 The next peer to join the namespace is peer 3, whose Node-ID is 3. 469 Peer 3 starts from level 2. At that level, peer 3 stores its 470 RedirServiceProvider record in the same interval I(2,3) that already 471 contains the Node-ID of peer 2. Since peer 3 has the numerically 472 highest Node-ID in the tree node associated with I(2,3), peer 3 473 continues up the tree. Peer 3 stores its RedirServiceProvider record 474 also at levels 1 and 0 since its Node-ID is numerically highest among 475 the Node-IDs stored in the intervals to which its own Node-ID 476 belongs. Peer 3 also does a downward walk which starts from level 2 477 (i.e., the starting level). Since peer 3 is not the only node in 478 interval I(2,3), it continues down the tree to level 3. The downward 479 walk ends at this level since peer 3 is the only service provider in 480 the interval I(3,3). 482 The third peer to join the namespace is peer 7, whose Node-ID is 7. 483 Like the two earlier peers, also peer 7 starts from level 2 because 484 this is the first registration it performs. Peer 7 stores its 485 RedirServiceProvider record at level 2. At level 1, peer 7 has the 486 numerically highest (and lowest) Node-ID in its interval I(1,7) 487 (because it is the only node in interval I(1,7); peers 2 and 3 are 488 stored in the same tree node but in a different interval) and 489 therefore it stores its Node-ID in the tree node associated with that 490 interval. Peer 7 also has the numerically highest Node-ID in the 491 interval I(0,7) associated with its Node-ID at level 0. Finally, 492 peer 7 performs a downward walk, which ends at level 2 because peer 7 493 is the only node in its interval at that level. 495 The final peer to join the ReDiR tree is peer 4, whose Node-ID is 4. 496 Peer 4 starts by storing its RedirServiceProvider record at level 2. 497 Since it has the numerically lowest Node-ID in the tree node 498 associated with interval I(2,4), it continues up in the tree to level 499 1. At level 1, peer 4 stores its record in the tree node associated 500 with interval I(1,4) because it has the numerically lowest Node-ID in 501 that interval. Next, peer 4 continues to the root level, at which it 502 stores its RedirServiceProvider record and finishes the upward walk 503 since the root level was reached. Peer 4 also does a downward walk 504 starting from level 2. The downward walk stops at level 2 because 505 peer 4 is the only peer in the interval I(2,4). 507 8. Overlay Configuration Document Extension 509 This document extends the RELOAD overlay configuration document by 510 adding a new element "branching-factor" inside the new "REDIR" kind 511 element: 513 redir:branching-factor: The branching factor of the ReDir tree. The 514 default value is 10. 516 This new element is formally defined as follows: 518 namespace redir = "urn:ietf:params:xml:ns:p2p:service-discovery" 520 parameter &= element redir:branching-factor { xsd:unsignedInt } 522 The 'redir' namespace is added into the element 523 in the overlay configuration file. 525 9. Security Considerations 527 There are no new security considerations introduced in this document. 528 The security considerations of RELOAD [I-D.ietf-p2psip-base] apply. 530 10. IANA Considerations 532 10.1. Access Control Policies 534 This document introduces one additional access control policy to the 535 "RELOAD Access Control Policy" Registry: 537 NODE-ID-MATCH 539 This access control policy was described in Section 5. 541 10.2. Data Kind-ID 543 This document introduces one additional data Kind-ID to the "RELOAD 544 Data Kind-ID" Registry: 546 +--------------+------------+----------+ 547 | Kind | Kind-ID | RFC | 548 +--------------+------------+----------+ 549 | REDIR | 104 | RFC-AAAA | 550 +--------------+------------+----------+ 552 This Kind-ID was defined in Section 6. 554 10.3. ReDiR Namespaces 556 IANA SHALL create a "ReDiR Namespaces" Registry. Entries in this 557 registry are strings denoting ReDiR namespace values. The initial 558 contents of this registry are: 560 +----------------+----------+ 561 | Namespace | RFC | 562 +----------------+----------+ 563 | turn-server | RFC-AAAA | 564 +----------------+----------+ 565 | voice-mail | RFC-AAAA | 566 +----------------+----------+ 568 11. Acknowledgments 570 The authors would like to thank Marc Petit-Huguenin for his comments 571 on the draft. 573 12. References 575 12.1. Normative References 577 [I-D.ietf-p2psip-base] 578 Jennings, C., Lowekamp, B., Rescorla, E., Baset, S., and 579 H. Schulzrinne, "REsource LOcation And Discovery (RELOAD) 580 Base Protocol", draft-ietf-p2psip-base-19 (work in 581 progress), October 2011. 583 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 584 Requirement Levels", BCP 14, RFC 2119, March 1997. 586 12.2. Informative References 588 [I-D.ietf-p2psip-concepts] 589 Bryan, D., Matthews, P., Shim, E., Willis, D., and S. 590 Dawkins, "Concepts and Terminology for Peer to Peer SIP", 591 draft-ietf-p2psip-concepts-04 (work in progress), 592 October 2011. 594 [Redir] Rhea, S., Godfrey, P., Karp, B., Kubiatowicz, J., 595 Ratnasamy, S., Shenker, S., Stoica, I., and H. Yu, "Open 596 DHT: A Public DHT Service and Its Uses". 598 Authors' Addresses 600 Jouni Maenpaa 601 Ericsson 602 Hirsalantie 11 603 Jorvas 02420 604 Finland 606 Email: Jouni.Maenpaa@ericsson.com 608 Gonzalo Camarillo 609 Ericsson 610 Hirsalantie 11 611 Jorvas 02420 612 Finland 614 Email: Gonzalo.Camarillo@ericsson.com