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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 QIRG K. Kompella 3 Internet-Draft M. Aelmans 4 Intended status: Standards Track Juniper Networks, Inc. 5 Expires: September 27, 2019 S. Wehner 6 QuTech 7 C. Sirbu 8 Redbit Networks 9 March 26, 2019 11 Advertising Entanglement Capabilities in Quantum Networks 12 draft-kaws-qirg-advent-02 14 Abstract 16 This document describes the use of link-state routing protocols on 17 classical links in Quantum Networks. It contains proposals for 18 additions to the IS-IS and OSPF protocols in order for them to 19 transport relevant information for a Quantum Network, specifically, 20 for the creation and manipulation of entangled pairs. The document 21 will describe some of the necessary attributes and some suggestions 22 of how this information may be used. 24 No Schrodinger's cats were harmed in the creation of this document. 26 Requirements Language 28 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 29 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 30 document are to be interpreted as described in RFC2119 [2]. 32 Status of This Memo 34 This Internet-Draft is submitted in full conformance with the 35 provisions of BCP 78 and BCP 79. 37 Internet-Drafts are working documents of the Internet Engineering 38 Task Force (IETF). Note that other groups may also distribute 39 working documents as Internet-Drafts. The list of current Internet- 40 Drafts is at https://datatracker.ietf.org/drafts/current/. 42 Internet-Drafts are draft documents valid for a maximum of six months 43 and may be updated, replaced, or obsoleted by other documents at any 44 time. It is inappropriate to use Internet-Drafts as reference 45 material or to cite them other than as "work in progress." 47 This Internet-Draft will expire on September 27, 2019. 49 Copyright Notice 51 Copyright (c) 2019 IETF Trust and the persons identified as the 52 document authors. All rights reserved. 54 This document is subject to BCP 78 and the IETF Trust's Legal 55 Provisions Relating to IETF Documents 56 (https://trustee.ietf.org/license-info) in effect on the date of 57 publication of this document. Please review these documents 58 carefully, as they describe your rights and restrictions with respect 59 to this document. Code Components extracted from this document must 60 include Simplified BSD License text as described in Section 4.e of 61 the Trust Legal Provisions and are provided without warranty as 62 described in the Simplified BSD License. 64 Table of Contents 66 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 67 1.1. Definitions and Notation . . . . . . . . . . . . . . . . 4 68 2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 6 69 3. Theory of Operation . . . . . . . . . . . . . . . . . . . . . 7 70 3.1. Multihop Entanglement . . . . . . . . . . . . . . . . . . 8 71 3.2. Distillation . . . . . . . . . . . . . . . . . . . . . . 9 72 3.3. Node Properties . . . . . . . . . . . . . . . . . . . . . 9 73 3.4. Link Properties . . . . . . . . . . . . . . . . . . . . . 10 74 4. The (Ab)use of Protocols . . . . . . . . . . . . . . . . . . 10 75 4.1. A Brief Primer on Link-state Protocols . . . . . . . . . 10 76 4.2. Node Properties . . . . . . . . . . . . . . . . . . . . . 12 77 4.3. Link Properties . . . . . . . . . . . . . . . . . . . . . 12 78 5. Security Considerations . . . . . . . . . . . . . . . . . . . 13 79 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 80 7. Editorial Comments . . . . . . . . . . . . . . . . . . . . . 13 81 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 82 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 83 9.1. Normative References . . . . . . . . . . . . . . . . . . 14 84 9.2. Informative References . . . . . . . . . . . . . . . . . 14 85 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 87 1. Introduction 89 Quantum networking is an emerging field using the strange (even 90 counterintuitive) properties of quantum mechanics to bring new, 91 useful capabilities to computing and networking. One of these is 92 "entanglement" [8], where the state of a group of particles must be 93 described as a unit -- it cannot be decomposed to the state of each 94 particle independently. Entangled pairs (often called EPR pairs, 95 abbreviated here as EP) of particles can be used for quantum 96 teleportation [10] and for quantum key distribution (QKD) [14]. 98 A Quantum Network consists of quantum nodes and links. Here, we will 99 be concerned with controllable quantum nodes (CQN) that allow control 100 decisions. We posit a classical network parallel to the quantum 101 network, with classical nodes (CN) and links. A classical node is 102 colocated with a quantum node; a classical link may be a fiber or 103 wavelength parallel to the corresponding quantum link. The existence 104 of such a classical link is required by most quantum methods to 105 create EPs deterministically or in a heralded fashion, where the 106 creation of EPs is conditioned on a specific signal. To make useful 107 decisions, it is desirable to augment this data to describe the 108 capabilities and states of quantum nodes and links. At current time 109 there is a need for classical links besides quantum links. In the 110 future this might change into a situation where classical links will 111 perhaps become obsolete. 113 This document proposes to carry entanglement capability data as Type 114 Length Values (TLVs) over IS-IS or OSPF link-state advertisements 115 over the corresponding classical network. A subset of the CQNs may 116 run quantum applications such as QKD; these nodes may want to 117 initiate multihop EPs. 119 Once an EP is created, the state of one particle ("quantum bit" or 120 qubit) of an EP can be transferred to another qubit within the same 121 QN by a process known as swapping or a SWAP gate ([12]). Also, 122 several pairs of imperfectly entangled qubits can be "distilled" 123 ([13]) to fewer but "better entangled" qubits. 125 Long distance entanglement can be produced from piecewise short 126 distance entanglement: Given an EP between CQN A and CQN B, and 127 another EP between CQN B and CQN C, one can create an EP between CQN 128 A and CQN C by a process known as an "entanglement swap". These 129 operations can be used to manipulate EPs to improve their lifetimes 130 or their quality, or to create multihop EPs. Physically, qubits can 131 be realized in many ways. For example, they can be represented by 132 the energy levels of Nitrogen Vacancy (NV) Centers in diamond ([16], 133 [17]). Logically, a qubit can be classified as a "communication 134 qubit", a "traveling qubit" or a "storage qubit". 136 This document primarily discusses the exchange of quantum 137 capabilities over a classical network. Some illustrative examples of 138 how these capabilities can be used in a quantum network may be given, 139 but this document should not be considered authoritative on these 140 procedures. 142 1.1. Definitions and Notation 144 The following terms are used in this document: 146 Quantum link: A quantum link is a connection transporting traveling 147 qubits, typically photons. This could be a physical link, or by 148 means of teleportation over pre-established entanglement amongst 149 distant network nodes. Such pre-shared entanglement effectively 150 forms a shortcut - a virtual quantum link - which can be used 151 exactly once. This document does not describe the usage of these 152 links itself. 154 Classical link: A classical link is a connection transporting 155 packets. This could be a physical or virtual link carried over a 156 (MPLS) network. The proposed extensions in this document use 157 these links to exchange capabilities. 159 Controllable Quantum Node (CQN): A controllable quantum node is a 160 quantum device consisting of at least one qubit, capable of 161 performing (a subset of) the following operations described in 162 detail below: storing qubits for some amount of time, performing 163 quantum operations such as entanglement distillation and 164 entanglement swapping, and producing entanglement between the 165 nodes and traveling qubits. The latter are generally realized 166 using photons over fibers or through free space. 168 The term controllable refers to the fact that external control in 169 software is capable of selecting the desired operations and qubits 170 to use. Such nodes can be quantum repeaters that allow choices of 171 operations to be made, as well as quantum end nodes capable of 172 executing complex application protocols [14]. Quantum repeaters 173 that merely allow timing control, such as automatic entanglement 174 swapping whenever qubits arrive in a specific timing interval, 175 will not be referred to as CQN. Such automated repeaters can be 176 seen as lying at the quantum physical layer and do not enter 177 routing or other decision making, apart from being switched on or 178 off, and hence are not relevant to advertisement protocols like 179 the ones considered here. 181 Quantum end node (QEN): In this document, a quantum end node [14] is 182 one of a pair of quantum nodes forming a entanglement via a 183 sequence of zero or more CQNs. Quantum end nodes typically run a 184 higher-layer quantum application such as QKD. 186 Entangled Pair (EP): An entangled pair is a special state of two 187 qubits, known as an EPR pair [8]. An entangled pair of qubits c@A 188 and c@B is denoted [[c@A, c@B]]. 190 The process of entangling two particles c@A and c@B is denoted as 191 follows: 193 ent(c@A, c@B) -> [[c@A, c@B]] 195 ent(c@A, c@B) may take time T and succeed with probability P, and 196 yield an entangled pair [[c@A, c@B]] of fidelity F. 198 Fidelity: A measure of the quality of the entanglement of an EP QFid 199 [11]). Fidelity lies in the interval [0, 1] where a higher value 200 indicates better quality; usable fidelity values lie in the half- 201 open interval (0.5, 1]. 203 Communication qubit: A qubit is called a communication qubit if it 204 is possible to produce entanglement between this qubit and a 205 traveling photon. This can be done by emission from the quantum 206 node, that is, entanglement is produced between the qubit and the 207 photon which is emitted from the quantum node. This process has 208 been demonstrated in a number of physical systems that can be used 209 as quantum nodes such as NV in diamond ([16], [17]), Ion Traps 210 ([18]) and Neutral Atoms ([19]). An example of a communication 211 qubit is the electron spin of the NV in diamond system ([15]). 212 Entanglement between a communication qubit and traveling photons 213 can also be produced by absorption. Examples include atomic 214 ensemble memories ([20]). 216 A communication qubit c at CQN A is denoted by c@A, or simply c 217 (if the node A is understood). 219 Storage qubit: A qubit is called a storage qubit if the node has the 220 capability to use this qubit as a (temporary) quantum memory, but 221 the qubit cannot serve as a communication qubit. To make storage 222 qubits useful a node is required to possess the ability to 223 transfer the state of a communication qubit to a storage qubit. 224 An example of a storage qubit is the nuclear spin in the NV in 225 diamond system [16]. 227 A storage qubit s at node B is denoted s@B. 229 Swap: Two qubits located in the same CQN can interchange states 230 ([13]). For example, the states of a communication qubit and a 231 storage qubit at A can be swapped as follows: 233 swap(c@A, s@A) 235 If c@A was entangled with c@B, the result is that s@A is now 236 entangled with c@B. 238 Distillation: Distillation is the process of turning a large number 239 of weakly entangled states into a smaller number of highly 240 entangled states ([13]). 242 For example, EPs [[c1@A, c1@B]] and [[c2@A, c2@B]] of fidelities 243 F1 and F2 respectively may be distilled as follows: 245 dist([[c1@A, c1@B]], [[c2@A, c2@B]]) -> [[c3@A, c3@B]] 247 If distillation is successful, the fidelity F3 of [[c3@A, c3@B]] 248 will be higher than F1 and F2. 250 Entanglement Swap: Given two EPs [[c@A, c1@B]] and [[c2@B, c@C]], 251 one can perform an entanglement swap: 253 entSwap([[c@A, c1@B]], [[c2@B, c@C]]) -> [[c@A, c@C]] 255 to create a new EP between c@A and c@C. This is how "multihop" 256 EPs are created from a sequence of "single-hop" EPs. 258 The swap operation can also be used within a CQN. A possible use 259 case is when there aren't enough communication qubits to create 260 the needed EPs. If, in the above example, B doesn't have two 261 communication qubits c1 and c2, the following can be done: 263 ent(c@A, c@B) -> [[c@A, c@B]] # entangle 264 swap(c@B, s@B) -> [[c@A, s@B]] # swap EP to storage qubit 265 ent(c@B, c@C) -> [[c@B, c@C]] # use freed up qubit c@B 266 entSwap(c@A, c@B) -> [[s@B, c@C]] # create multihop EP 268 2. Motivation 270 Consider the following (very simple) quantum network consisting of 271 QENs A and B, and CQNs X, Y, Z, U, V. The goal is to create an EP 272 between qubits at A and at B, perhaps for the high-level task of QKD 273 between A and B. 275 X - Y - Z 276 . . 277 A B A, B: QEN 278 . . 279 U --- V X, Y, Z, U, V: CQNs 281 From A's point of view, here are a number of questions: 283 1. Is B reachable from A via quantum links that allow EP creation? 285 2. If so, along what sequence(s) of quantum nodes? 286 3. Can each pair of adjacent CQNs in this sequence form EPs? If so, 287 how long will it take, and what fidelity can be expected? 289 4. If each pair of adjacent CQNs successfully forms EPs of 290 sufficient fidelity, can these be swapped to form a multihop EP 291 between A and B? 293 5. If a multihop EP between A and B were to be formed, would it be 294 of good enough fidelity, or should a second multihop EP be formed 295 and the two EPs distilled into one high fidelity EP? How many 296 times should this process be repeated? 298 6. If the overall answer is Yes, should A proceed via sequence A, X, 299 Y, Z, B, or sequence A, U, V, B? 301 This document aims to provide all CQNs in a quantum network with the 302 information they need to answer such questions, and to create EPs at 303 their desired fidelity and speed. 305 3. Theory of Operation 307 A CQN contains one or more communication qubits and one or more 308 storage qubits. Many proposals exist for producing EPs between 309 remote quantum nodes (see for example [16], [17], [18], [20]). 310 Abstractly, these result in the generation of EPs with fidelity F 311 after an expected time t. To give an example, we describe the 312 generation of EPs that has been implemented in NV in diamond ([16]), 313 and Ion Traps ([18]). The largest distance for producing long-lived 314 entanglement is presently 1.3kms ([17]). To entangle a pair of 315 communication qubits, the QNs send carefully timed photons towards 316 the HS. If the process is successful, HS sends an OK message to both 317 QNs. 319 +----------+ +----------+ 320 | | c-chan +------------+ c-chan | | 321 | Control- | <-------> | Heralding | <-------> | Control-| 322 | lable | | Station | | lable | 323 | Quantum | *~~~~~~~> | | <~~~~~~~* | Quantum | 324 | Node | q-chan +------------+ q-chan | Node | 325 | A | | B | 326 | | <----------------------------------> | | 327 +----------+ classical network control plane +----------+ 329 The classical network control plane is of particular interest here as 330 it would be used by the proposed protocol to advertise and exchange 331 information about the capabilities of the CQNs to generate 332 entanglement. This classical channel exists between all CQNs and is 333 shared with other application specific control and data plane 334 traffic. 336 3.1. Multihop Entanglement 338 resulting entanglement 339 *~~~~~~~~~~~~~~~~~~~~~~~~~~~~* 340 +-+ +-+ +-+ 341 |A+----------------------------+B+----------------------------+C| 342 +-+ A-B Link properties +-+ +-+ 343 [(F1,t1), (F2,t2)] Node B properties: 344 - Number of Communication Qubits 345 - Number of Storage Qubits 346 Node capabilities (operations): 347 - Swap comm <-> storage 348 - Entanglement swap 349 - [(Distillation scheme, time)...] 351 In the figure above, an example request for an entangled pair between 352 nodes A and B will be affected by the following properties: 354 o A chosen combination of F(idelity) and t(ime) duration to produce 355 an entanglement at the respective Fidelity. These parameters 356 roughly equate to the quality of the link, the accuracy with which 357 the nodes can use the link, and the delay in classical networking. 359 o The actual capability of nodes A and B to make use of the 360 communication qubits. 362 A new EP creation between CQNs B and C will similarly be affected by 363 the same parameters as above. 365 resulting entanglement 366 *~~~~~~~~~~~~~~~~~~~~~~~~~~~~* *~~~~~~~~~~~~~~~~~~~~~~~~~~~~* 367 +-+ +-+ +-+ 368 |A+----------------------------+B+----------------------------+C| 369 +-+ +-+ B-C Link properties +-+ 370 [(F1,t1), (F2,t2)] 372 And finally, with an entanglement swap operation at node B (which is 373 a node specific capability and has a specific duration) we end up 374 with an A-C EP: 376 *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~* 377 +-+ +-+ +-+ 378 |A+----------------------------+B+----------------------------+C| 379 +-+ +-+ +-+ 380 Node B entanglement swap operation 382 3.2. Distillation 384 If a pair of CQNs A and B share a number of EPs of insufficient 385 quality, they may be combined into a single EP of higher quality by 386 distillation. To do so, these CQNs need to agree on which 387 distillation scheme to use before distillation can proceed. This 388 does not necessarily need to be via communication between A and B, if 389 one agrees upon a deterministic procedure of selecting one. This 390 document suggests the following procedure: 392 1. A and B look at the distillation schemes that both advertise in 393 common. 395 2. If there is none in common, stop. Distillation is not possible. 397 3. If there is a non-trivial subset in common, the first scheme in 398 the node with the lower router ID is to be used by A and B. 400 Given a chosen distillation scheme (S,t,p), an additional time delay 401 will be added for the actual operation: For a 2:1 distillation scheme 402 between nodes A and B, 2 EPs need to be produced followed by an 403 operation on A and B that produces 1 EP. This operation will take 404 time some expected time t, and succeed with probability p. 406 2:1 distillation (S,t,p) 407 *~~~~~~~~~~~~~~~~~~~~~~~~~~~~* 408 *~~~~~~~~~~~~~~~~~~~~~~~~~~~~* 409 +-+ +-+ +-+ 410 |A+----------------------------+B+----------------------------+C| 411 +-+ A-B Link properties +-+ +-+ 412 [(F1,t1), (F2,t2)] 414 3.3. Node Properties 416 We are interested in exposing the properties of CQNs (including QENs) 417 to allow sophisticated decision making, for example in the creation 418 of entanglement. These properties include: 420 1. Number of communication qubits. The number of communication 421 qubits determines the number of entangled pairs that the node can 422 produce simultaneously. 424 2. Number of storage qubits 426 3. Possible operations, along with their execution time and 427 probability of success: 429 1. Swap between communication and storage qubits 430 2. Entanglement swap 432 3. List of supported distillation schemes (in order of 433 preference). 435 Note that several other parameters can be advertised, such as the T1 436 and T2 times for a qubit's decoherence. These are omitted for now, 437 instead just giving the decay of the fidelity of an EP. If deemed 438 useful, T1 and T2 times can additionally be advertised. 440 3.4. Link Properties 442 A list of (Fn,tn) pairs describing the tradeoffs of a possible 443 entanglement produced by two nodes (the ends of said link): tn is the 444 time to produce an entangled pair with fidelity Fn. 446 4. The (Ab)use of Protocols 448 The routing protocols IS-IS and/or OSPF could be used in order to 449 advertise entanglement capabilities. This section describes the 450 additional data fields needed in order to facilitate the objective. 452 4.1. A Brief Primer on Link-state Protocols 454 This document suggests the use of a link-state protocol to distribute 455 the capabilities of CQNs to create entanglement. This section offers 456 a short introduction to link-state protocols for those not familiar 457 with them. 459 Consider a directed graph G=(V, E) with vertices (nodes) V and edges 460 (links) E. Consider also G'=(V', E'); there is a 1-1 mapping from V' 461 to V and from E' to E such that e1' = (v1', v2') is in E' iff e1 = 462 (v1, v2) is in E and v1' maps to v1 and v2' maps to v2. G' 463 represents the quantum network; V' represents the set of CQNs, and E' 464 the set of quantum links between pairs of CQNs; G represents a 465 classical network parallel to G'; that is, each CQN v' has a 466 corresponding classical node v. v plays a dual role: it is the 467 control node for v', and proxies on behalf of v' in the link-state 468 protocol. 470 The basic objective of a link-state protocol is to "flood" properties 471 of nodes and (directed) links to all nodes in the network. This is 472 accomplished by means of "link-state advertisements" (LSAs) that each 473 node originates and sends to its immediate neighbors. The neighbors 474 in turn send received LSAs to their own neighbors; this process 475 repeats until every node receives every LSA (hence the term 476 "flooding"). The focus of LSAs is the link properties (hence _link- 477 state_ advertisements), although node properties are also advertised. 479 There are mechanisms to prevent looping of LSAs, and for reliable 480 flooding. There is also a sequence number by which a more recent 481 update of an LSA can be identified as such, and a mechanism for 482 "aging out" LSAs belonging to nodes no longer in the network. In 483 what follows, quantum node and link properties are added to the link- 484 state advertisements of the corresponding classical node. Note that 485 link properties need not be symmetric; that is, the link properties 486 of (v, w) need not be the same as those of (w, v). 488 The net result of flooding is that every node has the same picture of 489 the network (modulo LSAs in flight); in particular, each node knows 490 the overall topology and connectivity of the network, and can use 491 this information to make decisions. In a classical network, such a 492 decision could be to compute a shortest path; for the quantum 493 network, it could be choosing a feasible path (i.e., sequence of 494 CQNs) for a multihop entanglement. Note that a node doesn't really 495 know when it has complete and up-to-date information about the 496 network; LSA updates may be originated at any time. Usually, this is 497 okay: for example, if a node v learns enough of the network to have a 498 path to another node w, it can compute a multihop entanglement to w. 499 Subsequent updates may provide a more optimal (or higher probability) 500 entanglement path. There are heuristics one can apply to guess that 501 the link-state database (LSDB) (i.e., the union of all LSAs) is 502 complete-ish; however, as nodes (and links) can fail or disconnect, 503 there really is no such thing as "the full LSDB". 505 Each node v is identified by a "router ID" (an IP address uniquely 506 allocated to v), denoted by rid(v). A link L = (v, w) is identified 507 by (rid(v), i) where i is an index allocated by v for L unique for 508 each link emanating from v. (L may also be identified by IP 509 addresses, but we'll ignore that for now.) It is generally expected 510 that a directed link (v, w) is matched by a link (w, v); if not, (v, 511 w) is ignored from subsequent consideration; in particular, no link 512 properties are advertised for this link by v. Note that a pair of 513 nodes may have multiple links between them; for simplicity, the 514 notation will not be extended to indicate this. We'll assume rid(v') 515 = rid(v) and the index allocated to a quantum link e' is the same as 516 that of the corresponding classical link e. 518 Let v, w be a pair of neighboring nodes, and let L1 = (v, w) and L2 = 519 (w, v) in E be directed links in opposite directions between v and w 520 with identifiers (rid(v), i1) and (rid(w), i2) respectively (where i1 521 is the index allocated for L1 by v, and similarly for i2)). As a 522 first step in running a link-state protocol, v runs a "hello 523 protocol" all its links; in particular, over L1. Similarly, w will 524 run the hello protocol over L2. The hello protocol serves to 525 exchange the indices i1 and i2, and thus identify (rid(v), i1) as the 526 reverse link of (rid(w), i2). This allows both v and w to correlate 527 the link properties of L1 and L2. If the hello protocol fails 528 between v and w, neither node includes link properties for the link 529 in their LSAs. 531 Once the hello protocol has been run on all links, v starts the 532 process of generating and sending its own LSA over all its links, and 533 of receiving the current LSDB from its neighbors. Note that an LSA 534 originated by v must propagate unchanged across the network; only v 535 is allowed to change it (and such a change must be accompanied by 536 updating the LSA's sequence number). Such an update is triggered by 537 a new link coming up, an existing link going down, or a node or link 538 property changing. 540 IS-IS and OSPF are in principle similar, although the details of the 541 protocol mechanisms and encodings vary. In both protocols, a Type- 542 Length-Value (TLV) is used to encode most node and link properties. 543 In IS-IS, TLVs are used for all properties, and a single type of LSA 544 is used; in OSPF, there are several types of LSAs, and many (but not 545 all) properties are encoded as TLVs. 547 [1] has examples of "standard" LSAs for routing; [4] has the so- 548 called Traffic Engineering LSAs. 550 4.2. Node Properties 552 Here, we give a protocol-independent description of quantum node 553 properties; later documents will specify the encoding specifically 554 for IS-IS and OSPF. 556 Note that the following list of node properties is a strawman; all 557 details are subject to change, and other properties may be added as 558 needed. 560 The following node properties are added to the appropriate LSA: 562 563 564 565 566 568 4.3. Link Properties 570 Only one link property is listed. It gives the time-fidelity 571 tradeoffs of an entanglement operation as a list: 573 ... 575 This is interpreted as follows: an entanglement operation may be 576 initiated between nodes v and w over link (v, w). Depending on how 577 fast one wants to complete (time-i), the list gives the corresponding 578 fidelity of the resulting entanglement (fid-i). time-i is given in 579 nanoseconds; fid-i as a number between 0 and 999999. THe denominator 580 is 1000000. 582 Note that this link property is symmetric, as entanglement is 583 initiated simultaneously at v and w. 585 5. Security Considerations 587 It is not anticipated that adding these extensions to IS-IS and OSPF 588 will present new security hazards to those protocols. Since however 589 a common application of entangled pairs is for security purposes 590 (such as QKD), it is worth investigating whether this application 591 places a higher burden of security on the underlying protocols. 593 6. Acknowledgments 595 The authors would like to thank the following people for their 596 contributions and support to this document: Vesna Manojlovic, 597 Marcello Caleffi and Rodney Van Meter. Kompella would also like to 598 thank Bruno Rijsman for encouraging him to learn about Quantum 599 Computing and Networking. 601 Also: 603 _,'| _.-''``-...___..--';) 604 /_ \'. __..-' , ,--...--''' 605 <\ .`--''' ` /' 606 `-';' ; ; ; 607 __...--'' ___...--_..' .;.' 608 (,__....----''' (,..--'' 610 7. Editorial Comments 612 It could be worth investigating the use of a distance-vector routing 613 protocol to limit flooding. 615 8. IANA Considerations 617 There are no requests as yet to IANA for this document. 619 9. References 621 9.1. Normative References 623 [1] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and 624 dual environments", RFC 1195, DOI 10.17487/RFC1195, 625 December 1990, . 627 [2] Bradner, S., "Key words for use in RFCs to Indicate 628 Requirement Levels", BCP 14, RFC 2119, 629 DOI 10.17487/RFC2119, March 1997, 630 . 632 [3] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 633 (TE) Extensions to OSPF Version 2", RFC 3630, 634 DOI 10.17487/RFC3630, September 2003, 635 . 637 [4] Li, T. and H. Smit, "IS-IS Extensions for Traffic 638 Engineering", RFC 5305, DOI 10.17487/RFC5305, October 639 2008, . 641 [5] Ishiguro, K., Manral, V., Davey, A., and A. Lindem, Ed., 642 "Traffic Engineering Extensions to OSPF Version 3", 643 RFC 5329, DOI 10.17487/RFC5329, September 2008, 644 . 646 [6] Aggarwal, R. and K. Kompella, "Advertising a Router's 647 Local Addresses in OSPF Traffic Engineering (TE) 648 Extensions", RFC 5786, DOI 10.17487/RFC5786, March 2010, 649 . 651 9.2. Informative References 653 [7] "Qubit", . 655 [8] "Quantum Entanglement", 656 . 658 [9] "Quantum Network", 659 . 661 [10] "Quantum Teleportation", 662 . 664 [11] "Quantum Fidelity", . 667 [12] Wehner, S., Elkouss, D., and R. Hanson, "Quantum internet: 668 A vision for the road ahead", Science 362, 6412, 2018. 670 [13] Rozpedek, F., Schiet, T., Thinh, L., Elkouss, D., Doherty, 671 A., and S. Wehner, "Optimizing practical entanglement 672 distillation", Phys. Rev. A 97, 062333, 2018, 673 . 675 [14] "Quantum Key Distribution", 676 . 678 [15] "Nitrogen-vacancy center", 679 . 681 [16] Humphreys, P., "Deterministic delivery of remote 682 entanglement on a quantum network", Nature 558, 2018. 684 [17] Hensen, B. and , "Loophole-free Bell inequality violation 685 using electron spins separated by 1.3 kilometres", 686 Nature 526, 2015. 688 [18] Hucul, D. and , "Modular entanglement of atomic qubits 689 using photons and phonons", Nature Physics 11(1), 2015. 691 [19] Noelleke, C. and , "Efficient Teleportation Between Remote 692 Single-Atom Quantum Memories", Physical Review 693 Letters 110, 140403, 2013. 695 [20] Sangouard, N. and , "Quantum repeaters based on atomic 696 ensembles and linear optics", Reviews of Modern 697 Physics 83, 33, 2011. 699 Authors' Addresses 701 Kireeti Kompella 702 Juniper Networks, Inc. 703 1133 Innovation Way 704 Sunnyvale, CA 94089 705 USA 707 Email: kireeti.kompella@gmail.com 708 Melchior Aelmans 709 Juniper Networks, Inc. 710 Boeing Avenue 240 711 Schipol-Rijk, PZ 1119 712 The Netherlands 714 Email: maelmans@juniper.net 716 Stephanie Wehner 717 QuTech 718 Van der Waalsweg 122 719 Delft, LC 2611 720 The Netherlands 722 Email: s.d.c.wehner@tudelft.nl 724 Cristian Sirbu 725 Redbit Networks 726 Dublin 727 Republic of Ireland 729 Email: cristian@redbit.network