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ENC0/Times-Italic RE/Courier@0 ENC0/Courier RE/Times-Roman@0 ENC0/Times-Roman RE/Times-Bold@0 ENC0/Times-Bold RE/Courier-Bold@0 ENC0/Courier-Bold RE%%EndProlog%%Page: 1 1%%BeginPageSetupBP%%EndPageSetup/F0 10/Courier-Bold@0 SF(Internet Engineering Task Force)72 85 Q(PIM WG)210 E 240(INTERNET-DRAFT Mark)72 98 R(Handley/ICIR)6 E 144(draft-ietf-pim-bidir-05.ps Isidor)72 111 R(Kouvelas/Cisco)6 E(Tony Speakman/Cisco)390 124 Q(Lorenzo Vicisano/Cisco)372 137 Q(26 June 2002)432 150 Q(Expires: December 2002)372 163 Q/F1 14/Times-Bold@0 SF(Bi-dir)107.82 188 Q(ectional Pr)-.252 E(otocol Independent Multicast \(BIDIR-PIM\))-.252 E/F2 11/Times-Bold@0SF(Status of this Document)72 220 Q/F3 11/Times-Roman@0 SF(This documen\t is an Internet-Draft and is in full conformance with all pro)72 236.6Q(visions of Section 10 of)-.165 E(RFC2026.)72 249.6 Q(Internet-Drafts are w)72 266.2 Q(orking documents of the Internet Engineering T)-.11 E(ask F)-.88 E(orce \(IETF\), its areas,)-.165 E(and its w)72 279.2 Q(orking groups.)-.11 E(Note that other groups may also distrib)5.5 E(ute w)-.22 E(orking documents as)-.11 E(Internet-Drafts.)72 292.2 Q(Internet-Drafts are draft documents v)72 308.8 Q(alid for a maximum of six months and may be updated,)-.275 E(replaced, or obsoleted by other documents at an)72 321.8 Q 2.75(yt)-.165 G 2.75(ime. It)-2.75 F(is inappropriate to use Internet-Drafts)2.75 E(as reference material or to cite them other than as "w)72 334.8 Q(ork in progress.")-.11 E(The list of current Internet-Drafts can be accessed at http://www)72351.4 Q(.ietf.or)-.715 E(g/ietf/1id-abstracts.txt)-.198 E(The list of Internet-Draft Shado)72 368 Q 2.75(wD)-.275 G(irectories can be accessed at http://www)-2.75 E(.ietf.or)-.715 E(g/shado)-.198 E -.715(w.)-.275 G(html.).715 E(This document is a product of the IETF PIM WG.)72 384.6 Q(Comments should be addressed to the authors,)5.5 E(or the WG')72 397.6Q 2.75(sm)-.605 G(ailing list at pim@catarina.usc.edu.)-2.75 E F2(Abstract)267.534 416.6 Q F3(This document discusses Bi-directional PIM, a v)97 439.2 Q(ariant of PIM Sparse-Mode [9] that)-.275 E -.22(bu)97 452.2 S(ilds bi-\directional shared trees connecting multicast sources and recei).22 E-.165(ve)-.275 G(rs. Bi-).165 E(directional trees are b)97 465.2 Q(uilt using a f)-.22 E(ail-safe Designated F)-.11 E(orw)-.165 E(arder \(DF\) election)-.11 E(mechanism operating on each link of a multicast topology)97 478.2 Q 5.5(.W)-.715 G(ith the assistance of the)-5.94 E(DF)97 491.2 Q 2.75(,m)-.88G(ulticast data is nati)-2.75 E -.165(ve)-.275 G(ly forw).165 E(arded from sources to the Rendezv)-.11 E(ous-Point and)-.22 E(hence along the shared tree to recei)97 504.2 Q -.165(ve)-.275 G(rs without requiring source-speci\214c state.).165 E(The)5.5 E(DF election tak)97 517.2 Q(es place at RP disco)-.11 E -.165(ve)-.165 G(ry time and pro).165 E(vides a def)-.165 E(ault route to the RP)-.11 E(thus eliminating the requirement for data-dri)97 530.2 Q -.165(ve)-.275G 2.75(np).165 G(rotocol e)-2.75 E -.165(ve)-.275 G(nts.).165 E F2(Note on BIDIR-PIM status)72 556.2 Q F3(The dif)72 572.8 Q(ferences between this v)-.275 E(ersion of the BIDIR-PIM speci\214cation and draft-ietf-pim-bidir)-.165E(-)-.22 E(ne)72 585.8 Q(w-00.txt are mostly in the format of the infor\mation presented. As BIDIR-PIM has man)-.275 E(y)-.165 E(similarities in operation to Sparse-Mode PIM, the earlier v)72 598.8 Q(ersion of this spec relied hea)-.165 E(vily on the)-.22 E(no)72 611.8 Q2.75(wo)-.275 G(bsolete PIM-SM [11] speci\214cation. This re)-2.75 E(vision remo)-.275 E -.165(ve)-.165 G 2.75(st).165 G(his dependenc)-2.75E 2.75(ya)-.165 G(nd instead)-2.75 E(references the ne)72 624.8 Q 2.75(wS)-.275 G(parse-Mode documentation [9] where necessary)-2.75 E 2.75(.I)-.715 G 2.75(na)-2.75 G(ddition the method in)-2.75 E(which the pro\tocol speci\214cation is presented has been updated to follo)72 637.8 Q2.75(wt)-.275 G(he format of [9].)-2.75 E(Handle)72 769 Q(y/K)-.165 E(ouv)-.385 E(elas/Speakman/V)-.165 E 220.91(icisano [P)-.66 F(age 1])-.165 E EP%%Page: 2 2%%BeginPageSetupBP%%EndPageSetup/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 66.092(-DRAFT Expires:)-1.012 F(December 2002)2.75 E(June 2002)116.406 E/F1 13/Times-Bold@0 SF -1.196(Ta)239.126 85 S(ble of Contents)1.196 E/F2 10/Times-Roman@0 SF(1. Introduction)72 123 Q F0 11(.........................)12.31 G F2(3)11.5 E(2. T)72 135 Q(erminology)-.7 E F0 11(.........................)10.23 G F2(3)11.5 E(2.1. De\214nitions)82 147 Q F0 11(........................)13.55 G F2(3)11.5 E(2.2. Pseudocode Notation)82 159 Q F0 11(......................).23 G F2(4)11.5 E(3. Protocol Speci\214cation)72 171 Q F0 11(.......................).64G F2(5)11.5 E(3.1. BIDIR-PIM Protocol State)82 183 Q F0 11(....................)5.78 G F2(5)11.5 E(3.1.1. General Purpose State)92195 Q F0 11(....................)6.63 G F2(5)11.5 E(3.1.2. RP State)92207 Q F0 11(........................)5.77 G F2(6)11.5 E(3.1.3. Group State)92 219 Q F0 11(.......................)6.2 G F2(6)11.5 E(3.1.4. State Summarization Macros)92 231 Q F0 11(..................)6.9 G F2(7)11.5 E(3.2. PIM Neighbor Disco)82 243 Q-.15(ve)-.15 G(ry).15 E F0 11(....................)11.65 G F2(7)11.5 E(3.3. Data P)82 255 Q(ack)-.15 E(et F)-.1 E(orw)-.15 E(arding Rules)-.1E F0 11(...................)4.77 G F2(8)11.5 E(3.3.1. Source-Only Branches)92 267 Q F0 11(....................)4.69 GF2(8)11.5 E(3.4. PIM Join/Prune Messages)82 279 Q F0 11(....................)8.56 G F2(9)11.5 E(3.4.1. Recei)92 291 Q(ving \(*,G\) Join/Prune Messages)-.25 E F0 11(...............)13.41 GF2(9)11.5 E(3.4.2. Sending Join/Prune Messages)92 303 Q F0 11(..................)3.56 G F2(11)6.5 E(3.5. Designated F)82 315 Q(orw)-.15 E(arder \(DF\) Election)-.1 E F0 11(.................)7.59 G F2(13)6.5 E(3.5.1. DF Requirements)92 327 Q F0 11(.....................)10.92G F2(13)6.5 E(3.5.2. DF Election description)92 339 Q F0 11(...................)13.7 G F2(13)6.5 E(3.5.2.1. Bootstrap Election)102351 Q F0 11(....................)3.28 G F2(14)6.5 E(3.5.2.2. Loser Metric Changes)102 363 Q F0 11(...................)2.88G F2(14)6.5 E(3.5.2.3. W)102 375 Q(inner Metric Changes)-.4 E F0 11(..................)9.81 G F2(15)6.5 E(3.5.2.4. W)102 387 Q(inner Loses P)-.4 E(ath)-.15 E F0 11(....................)2.45 G F2(15)6.5 E(3.5.2.5. Late Router Starting Up)102 399 Q F0 11(..................)9.12 G F2(15)6.5 E(3.5.2.6. W)102 411 Q(inner Dies)-.4 E F0 11(......................).08 G F2(15)6.5 E(3.5.3. Election Protocol Speci\214cation)92 423 Q F0 11(.................)12.31 G F2(15)6.5 E(3.5.3.1. Election State)102 435 QF0 11(.....................)8.42 G F2(16)6.5 E(3.5.3.2. Election Messages)102 447 Q F0 11(....................)3.29 GF2(16)6.5 E(3.5.3.3. Election Ev)102 459 Q(ents)-.15 E F0 11(.....................)1.35 G F2(17)6.5 E(3.5.3.4. Election Notation)102471 Q F0 11(....................)7.17 G F2(17)6.5 E(3.5.3.5. Election State T)102 483 Q(ransitions)-.35 E F0 11(..................)2.52 G F2(17)6.5 E(3.6. T)82 495 Q(imers and Constants)-.35 E F0 11(.....................)12.38 G F2(20)6.5 E(3.7. BIDIR PIM P)82 507 Q(ack)-.15 E(et F)-.1 E(ormats)-.15 E F011(....................)1.46 G F2(22)6.5 E(3.7.1. DF Election P)92 519 Q(ack)-.15 E(et F)-.1 E(ormats)-.15 E F0 11(..................)10.35 G F2(22)6.5 E(3.7.2. Back)92 531 Q(of)-.1 E 2.5(fM)-.25 G(essage)-2.5 E F011(.....................)12.4 G F2(23)6.5 E(3.7.3. P)92 543 Q(ass Message)-.15 E F0 11(......................)12.88 G F2(24)6.5 E(3.7.4. Bidir Capable PIM-Hello Option)92 555 Q F0 11(.................)4.81 G F2(24)6.5 E(4. RP Disco)72 567 Q -.15(ve)-.15 G(ry).15 E F0 11(.........................)6.22 G F2(25)6.5 E(5. Security Considerations)72 579 Q F0 11(......................)7.17 GF2(25)6.5 E(5.1. Appendix A: Election Reliability Enhancements)82 591 QF0 11(..............)2.18 G F2(25)6.5 E(5.1.1. A.1 Missing P)92 603 Q(ass)-.15 E F0 11(.....................)12.17 G F2(25)6.5 E(5.1.2. A.2 Periodic W)92 615 Q(inner Announcement)-.4 E F0 11(................)4.26 G F2(25)6.5 E(5.2. Appendix B: Interoperability with le)82 627 Q -.05(ga)-.15 G .3-.15(cy c).05 H(ode).15 E F0 11(..............)9.49 G F2(26)6.5 E(5.3. Appendix C: Comparison with PIM-SM)82 639 Q F0 11(................)6.88 G F2(26)6.5 E(6. T)72 651 Q(odo list...)-.8 E F011(..........................)5.46 G F2(27)6.5 E(7. Authors' Addresses)72 663 Q F0 11(.......................)10.1 G F2(27)6.5 E(8. Ackno)72675 Q(wledgments)-.25 E F0 11(........................).76 G F2(27)6.5 E(9. References)72 687 Q F0 11(..........................)3.58 G F2(27)6.5 E(10. Inde)72 699 Q(x)-.15 E F0 11(...........................)6.63G F2(29)6.5 E F0(Handle)72 769 Q(y/K)-.165 E(ouv)-.385 E(elas/Speakman/V)-.165 E 220.91(icisano [P)-.66 F(age 2])-.165 E EP%%Page: 3 3%%BeginPageSetupBP%%EndPageSetup/F0 11/Times-Roman@0 SF(INTERNET)72 49 Q 66.092(-DRAFT Expires:)-1.012 F(December 2002)2.75 E(June 2002)116.406 E/F1 11/Times-Bold@0 SF(1.)72 85Q/F2 14/Times-Bold@0 SF(Intr)5.5 E(oduction)-.252 E F0(This document speci\214es Bi-directional PIM, a v)72 101.6 Q(ariant of PIM Sparse-Mode \(PIM-SM\) [9] that)-.275 E -.22(bu)72 114.6S(ilds bi-directional shared trees connecting multicast sources and rec\ei).22 E -.165(ve)-.275 G(rs.).165 E(PIM-SM constructs uni-directional shared trees that are used to forw)72131.2 Q(ard data from senders to)-.11 E(recei)72 144.2 Q -.165(ve)-.275G(rs of a multicast group.).165 E(PIM-SM also allo)5.5 E(ws the construction of source speci\214c trees, b)-.275 E(ut)-.22 E(th\is capability is not related to the protocol described in this document\.)72 157.2 Q(The shared tree for each multicast group is rooted at a mu\lticast router called the Rendezv)72 173.8 Q(ous)-.22 E(Point \(RP\). Dif)72 186.8 Q(ferent multicast group ranges can use sep\arate RPs within a PIM domain.)-.275 E(In unidirectional PIM-SM, there are tw)72 203.4 Q 2.75(op)-.11 G(ossible methods for distrib)-2.75 E(uting data pack)-.22 E(ets on the)-.11 E(shared tree. These dif)72 216.4 Q(fer in the w)-.275 E(ay pack)-.11 E(ets are forw)-.11 E(arded from a source to the RP:)-.11 E 7.15<8349>72 233 S(nitially when a source starts transmitting, its \214rst \hop router encapsulates data pack)-7.15 E(ets in)-.11 E(special control messages \(Re)83 246 Q(gisters\) which are unicast to the RP)-.165 E 2.75(.A)-1.221 G(fter reaching the RP the)-2.75 E(pack)83 259 Q(ets are decapsulated and distrib)-.11 E(uted on the shared tree.)-.22 E7.15<8341>72 275.6 S(transition from the abo)-4.4 E .33 -.165(ve d)-.165