draft-ietf-pim-bidir-04.ps

BCAST Implementation for NS2

H(istrib).165 E(ution mode can be made at a later stage.)-.22 E
(This is achie)5.5 E -.165(ve)-.275 G 2.75(db).165 G(y)-2.75 E -.22(bu)
83 288.6 S(ilding source speci\214c state on all routers along the path\
 between the source and the RP).22 E 5.5(.T)-1.221 G(his)-5.5 E
(state is then used to nati)83 301.6 Q -.165(ve)-.275 G(ly forw).165 E
(ard pack)-.11 E(ets from that source.)-.11 E(Both these mechanisms suf)
72 318.2 Q
(fer from problems. Encapsulation results in signi\214cant processing,)
-.275 E(bandwidth and delay o)72 331.2 Q -.165(ve)-.165 G(rheads. F).165
E(orw)-.165 E
(arding using source speci\214c state has additional protocol)-.11 E
(and memory requirements.)72 344.2 Q(Bi-directional PIM dispenses with \
both encapsulation and source state by allo)72 360.8 Q(wing pack)-.275 E
(ets to be)-.11 E(nati)72 373.8 Q -.165(ve)-.275 G(ly forw).165 E
(arded from a source to the RP using shared tree state. F)-.11 E
(or a complete discussion of)-.165 E
(the pros and cons of Bi-directional PIM consult appendix C.)72 386.8 Q
F1(2.)72 416.4 Q F2 -1.288(Te)5.5 G(rminology)1.288 E F0
(In this document, the k)72 433 Q .33 -.165(ey w)-.11 H
(ords "MUST", "MUST NO).055 E(T", "REQ)-.44 E(UIRED", "SHALL", "SHALL)
-.11 E(NO)72 446 Q(T", "SHOULD", "SHOULD NO)-.44 E
(T", "RECOMMENDED", "MA)-.44 E(Y", and "OPTION)-1.155 E(AL" are to)-.385
E(be interpreted as described in RFC 2119 and indicate requirement le)72
459 Q -.165(ve)-.275 G(ls for compliant PIM-SM).165 E(implementations.)
72 472 Q F1(2.1.)72 498 Q/F3 13/Times-Bold@0 SF(De\214nitions)5.5 E F0(\
This speci\214cation uses a number of terms to refer to the roles of ro\
uters participating in BIDIR-)72 514.6 Q 2.75(PIM. The)72 527.6 R(follo)
2.75 E(wing terms ha)-.275 E .33 -.165(ve s)-.22 H
(pecial signi\214cance for BIDIR-PIM:).165 E(MRIB)72 544.2 Q
(Multicast Routing Information Base.)105 557.2 Q
(This is the multicast topology table, which is)5.5 E(typically deri)105
570.2 Q -.165(ve)-.275 G 2.75(df).165 G
(rom the unicast routing table, or routing protocols such as MBGP that)
-2.75 E(carry multicast-speci\214c topology information. It is used by \
PIM for establishing the RPF)105 583.2 Q(interf)105 596.2 Q
(ace \(used in the forw)-.11 E
(arding rules\). In PIM-SM the MRIB is also used to mak)-.11 E(e)-.11 E
(decisions re)105 609.2 Q -.055(ga)-.165 G(rding where to forw).055 E
(ard Join/Prune messages whereas in BIDIR-PIM it is)-.11 E
(used as a source for routing metrics for the DF election process.)105
622.2 Q(Rendezv)72 638.8 Q(ous Point \(RP\):)-.22 E(An RP is a router t\
hat has been con\214gured to be used as the root of the distrib)105
651.8 Q(ution tree for)-.22 E 2.75(ar)105 664.8 S
(ange of multicast groups. Join messages from recei)-2.75 E -.165(ve)
-.275 G(rs for a group are sent to).165 E -.11(wa)-.275 G(rds the).11 E
(RP)105 677.8 Q(.)-1.221 E(Upstream)72 694.4 Q -1.265 -.88(To w)105
707.4 T(ards the root \(Rendezv).77 E
(ous-Point\) of the tree. The direction used by pack)-.22 E(ets tra)-.11
E -.165(ve)-.22 G(ling).165 E(from sources to the RP)105 720.4 Q(.)
-1.221 E(Handle)72 769 Q(y/K)-.165 E(ouv)-.385 E(elas/Speakman/V)-.165 E
163.16(icisano Section)-.66 F 2.75(2.1. [P)2.75 F(age 3])-.165 E EP
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/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(Do)72 85 Q(wnstream)-.275 E
-.836 -1.012(Aw a)105 98 T 2.75(yf)1.012 G
(rom the root of the tree. The direction on which pack)-2.75 E(ets tra)
-.11 E -.165(ve)-.22 G 2.75(lf).165 G(rom the RP to)-2.75 E(recei)105
111 Q -.165(ve)-.275 G(rs.).165 E(Designated F)72 127.6 Q(orw)-.165 E
(arder \(DF\):)-.11 E(The protocol presented in this document is lar)105
140.6 Q(gely based on the concept of a Designated)-.198 E -.165(Fo)105
153.6 S(rw).165 E(arder \(DF\). A single DF e)-.11 E
(xists for each RP on e)-.165 E -.165(ve)-.275 G
(ry link within a BIDIR-PIM).165 E(domain \(this includes both multi-ac\
cess and point-to-point links\). The DF is the router on)105 166.6 Q
(the link with the best unicast route to the RP)105 179.6 Q 5.5(.A)
-1.221 G(DF for a gi)-2.75 E -.165(ve)-.275 G 2.75(nR).165 G 2.75(Pi)
-2.75 G 2.75(si)-2.75 G 2.75(nc)-2.75 G(har)-2.75 E(ge of)-.198 E(forw)
105 192.6 Q(arding do)-.11 E(wnstream traf)-.275 E
(\214c onto the link, and forw)-.275 E(arding upstream traf)-.11 E
(\214c from the link)-.275 E(to)105 205.6 Q -.11(wa)-.275 G(rds the RP)
.11 E 5.5(.I)-1.221 G 2.75(td)-5.5 G
(oes this for all the bi-directional groups serv)-2.75 E(ed by the RP)
-.165 E 2.75(.T)-1.221 G(he DF on)-2.75 E 2.75(al)105 218.6 S(ink is al\
so responsible for interpreting IGMP information from local recei)-2.75
E -.165(ve)-.275 G(rs and).165 E
(processing Join messages from other routers on the link.)105 231.6 Q
(RPF Interf)72 248.2 Q(ace)-.11 E(RPF stands for "Re)105 261.2 Q -.165
(ve)-.275 G(rse P).165 E(ath F)-.165 E(orw)-.165 E 2.75(arding". The)
-.11 F(RPF Interf)2.75 E(ace of a router with respect to)-.11 E
(an address is the interf)105 274.2 Q
(ace that the MRIB indicates should be used to forw)-.11 E(ard pack)-.11
E(ets to)-.11 E(that address.)105 287.2 Q
(In the case of a BIDIR-PIM multicast group, the RPF interf)5.5 E
(ace is the)-.11 E(interf)105 300.2 Q(ace that w)-.11 E
(ould be used to send pack)-.11 E(ets to the RP for the group.)-.11 E
(RPF Neighbor)72 316.8 Q(The RPF Neighbor of a router with respect to a\
n address is the neighbor that the MRIB)105 329.8 Q
(indicates should be used to forw)105 342.8 Q(ard pack)-.11 E
(ets to that address. Note that in BIDIR-PIM, the)-.11 E(RPF neighbor f\
or a group is not necessarily the router on the RPF interf)105 355.8 Q
(ace that Join)-.11 E(messages for that group w)105 368.8 Q
(ould be directed to \(Join messages are directed to the DF on the)-.11
E(RPF interf)105 381.8 Q(ace for the group\).)-.11 E 12.529(TIB T)72
398.4 R(ree Information Base.)-.385 E
(This is the collection of state at a PIM router that has been created)
5.5 E(by recei)105 411.4 Q(ving PIM Join/Prune messages, PIM DF electio\
n messages and IGMP information)-.275 E(from local hosts.)105 424.4 Q
(It essentially stores the state of all multicast distrib)5.5 E
(ution trees at that)-.22 E(router)105 437.4 Q(.)-.605 E 3.355
(MFIB Multicast)72 454 R -.165(Fo)2.75 G(rw).165 E
(arding Information Base.)-.11 E
(The TIB holds all the state that is necessary to)5.5 E(forw)105 467 Q
(ard multicast pack)-.11 E(ets at a router)-.11 E 5.5(.H)-.605 G -.275
(ow)-5.5 G -2.365 -.275(ev e).275 H .88 -.44(r, a).275 H
(lthough this speci\214cation de\214nes).44 E(forw)105 480 Q
(arding in terms of the TIB, to actually forw)-.11 E(ard pack)-.11 E
(ets using the TIB is v)-.11 E(ery)-.165 E(inef)105 493 Q 2.75
(\214cient. Instead)-.275 F 2.75(ar)2.75 G
(eal router implementation will normally b)-2.75 E(uild an ef)-.22 E
(\214cient MFIB)-.275 E(from the TIB state to perform forw)105 506 Q
2.75(arding. Ho)-.11 F 2.75(wt)-.275 G
(his is done is implementation-speci\214c,)-2.75 E
(and is not discussed in this document.)105 519 Q/F1 11/Times-Bold@0 SF
(2.2.)72 548.6 Q/F2 13/Times-Bold@0 SF(Pseudocode Notation)5.5 E F0 1.76
-.88(We u)72 565.2 T(se set notation in se).88 E -.165(ve)-.275 G
(ral places in this speci\214cation.).165 E/F3 11/Courier@0 SF 6.6(A\()
72 581.8 S(+\) B)-6.6 E F0(is the union of tw)94 594.8 Q 2.75(os)-.11 G
(ets A and B.)-2.75 E F3 6.6(A\()72 611.4 S(-\) B)-6.6 E F0
(is the elements of set A that are not in set B.)94 624.4 Q F3(NULL)72
641 Q F0(is the empty set or list.)94 654 Q(In addition we use C-lik)72
670.6 Q 2.75(es)-.11 G(yntax:)-2.75 E 15.796(=d)72 687.2 S
(enotes assignment of a v)-15.796 E(ariable.)-.275 E 6.842(== denotes)72
703.8 R 2.75(ac)2.75 G(omparison for equality)-2.75 E(.)-.715 E(Handle)
72 769 Q(y/K)-.165 E(ouv)-.385 E(elas/Speakman/V)-.165 E 163.16
(icisano Section)-.66 F 2.75(2.2. [P)2.75 F(age 4])-.165 E EP
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(December 2002)2.75 E(June 2002)116.406 E 9.383(!= denotes)72 85 R 2.75
(ac)2.75 G(omparison for inequality)-2.75 E(.)-.715 E
(Braces { and } are used for grouping.)72 101.6 Q/F1 11/Times-Bold@0 SF
(3.)72 140.6 Q/F2 14/Times-Bold@0 SF(Pr)5.5 E(otocol Speci\214cation)
-.252 E F0(The speci\214cation of BIDIR-PIM is brok)72 157.2 Q
(en into se)-.11 E -.165(ve)-.275 G(ral parts:).165 E 7.15<8353>72 173.8
S(ection 3.1 details the protocol state stored.)-7.15 E 7.15<8353>72
190.4 S(ection 3.3 speci\214es the data pack)-7.15 E(et forw)-.11 E
(arding rules.)-.11 E 7.15<8353>72 207 S(ection 3.4 speci\214es the BID\
IR-PIM Join/Prune generation and processing rules.)-7.15 E 7.15<8344>72
223.6 S(esignated F)-7.15 E(orw)-.165 E
(arder \(DF\) election is speci\214ed in Section 3.5.)-.11 E 7.15<8350>
72 240.2 S(IM pack)-7.15 E(et formats are speci\214ed in Section 3.7.)
-.11 E 7.15<8341>72 256.8 S(summary of BIDIR-PIM timers and their def)
-4.4 E(ault v)-.11 E(alues is gi)-.275 E -.165(ve)-.275 G 2.75(ni).165 G
2.75(nS)-2.75 G(ection 3.6.)-2.75 E F1(3.1.)72 286.4 Q/F3 13
/Times-Bold@0 SF(BIDIR-PIM Pr)5.5 E(otocol State)-.234 E F0(This sectio\
n speci\214es all the protocol state that a BIDIR-PIM implementation sh\
ould maintain in)72 303 Q(order to function correctly)72 316 Q 5.5(.W)
-.715 G 2.75(et)-6.38 G(erm this state the)-2.75 E/F4 11/Times-Italic@0
SF -1.947 -.605(Tr e)2.75 H 2.75(eI).605 G(nformation Base)-2.75 E F0
(or TIB, as it holds the)2.75 E(state of all the multicast distrib)72
329 Q(ution trees at this router)-.22 E 5.5(.I)-.605 G 2.75(nt)-5.5 G
(his speci\214cation we de\214ne PIM)-2.75 E
(mechanisms in terms of the TIB.)72 342 Q(Ho)5.5 E(we)-.275 E -.165(ve)
-.275 G .88 -.44(r, o).165 H(nly a v).44 E(ery simple implementation w)
-.165 E(ould actually)-.11 E(implement pack)72 355 Q(et forw)-.11 E
(arding operations in terms of this state.)-.11 E
(Most implementations will use)5.5 E(this state to b)72 368 Q
(uild a multicast forw)-.22 E(arding table, which w)-.11 E
(ould then be updated when the rele)-.11 E -.275(va)-.275 G(nt).275 E
(state in the TIB changes.)72 381 Q
(Although we specify precisely the state to be k)72 397.6 Q
(ept, this does not mean that an implementation of)-.11 E
(PIM-SM needs to hold the state in this form.)72 410.6 Q
(This is actually an abstract state de\214nition, which is)5.5 E
(needed in order to specify the router')72 423.6 Q 2.75(sb)-.605 G(eha)
-2.75 E(vior)-.22 E 5.5(.A)-.605 G
(BIDIR-PIM implementation is free to hold)-2.75 E(whate)72 436.6 Q -.165
(ve)-.275 G 2.75(ri).165 G(nternal state it requires, and will still be\
 conformant with this speci\214cation so long as it)-2.75 E
(results in the same e)72 449.6 Q(xternally visible protocol beha)-.165
E(vior as an abstract router that holds the)-.22 E(follo)72 462.6 Q
(wing state.)-.275 E 1.76 -.88(We d)72 479.2 T -.275(iv).88 G
(ide TIB state into tw).275 E 2.75(os)-.11 G(ections:)-2.75 E(RP state)
72 495.8 Q(State that maintains the DF election information for each RP)
97 508.8 Q(.)-1.221 E(Group state)72 525.4 Q(State that maintains a gro\
up-speci\214c tree for groups that map to a gi)97 538.4 Q -.165(ve)-.275
G 2.75(nR).165 G -1.221(P.)-2.75 G(The state that should be k)72 555 Q
(ept is described belo)-.11 E 4.18 -.715(w. O)-.275 H 2.75(fc).715 G
(ourse, implementations will only maintain)-2.75 E
(state when it is rele)72 568 Q -.275(va)-.275 G(nt to forw).275 E
(arding operations - for e)-.11 E(xample, the "NoInfo" state might be)
-.165 E(assumed from the lack of other state information, rather than b\
eing held e)72 581 Q(xplicitly)-.165 E(.)-.715 E F1 2.75(3.1.1. General)
72 607 R(Pur)2.75 E(pose State)-.11 E F0 2.75(Ar)72 623.6 S
(outer holds the follo)-2.75 E
(wing state that is not speci\214c to a RP or group:)-.275 E F1
(Neighbor State:)97 640.2 Q F0 -.165(Fo)122 656.8 S 2.75(re).165 G
(ach neighbor:)-2.75 E 7.15<8349>147 673.4 S(nformation from neighbor')
-7.15 E 2.75(sH)-.605 G(ello)-2.75 E 7.15<834e>147 690 S(eighbor')-7.15
E 2.75(sG)-.605 G(en ID.)-2.75 E 7.15<834e>147 706.6 S(eighbor li)-7.15
E -.165(ve)-.275 G(ness timer \(NL).165 E(T\))-1.012 E(Handle)72 769 Q
(y/K)-.165 E(ouv)-.385 E(elas/Speakman/V)-.165 E 154.91(icisano Section)
-.66 F 2.75(3.1.1. [P)2.75 F(age 5])-.165 E EP
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/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 2.75
(3.1.2. RP)72 85 R(State)2.75 E F0 2.75(Ar)72 101.6 S
(outer maintains a multicast-group to RP mapping which is b)-2.75 E
(uilt through static con\214guration or)-.22 E
(by using an automatic RP disco)72 114.6 Q -.165(ve)-.165 G
(ry mechanism lik).165 E 2.75(eB)-.11 G(SR or A)-2.75 E(UT)-.605 E
(O-RP \(see section 4 \). F)-.198 E(or each)-.165 E
(BIDIR-PIM RP a router holds the follo)72 127.6 Q(wing state:)-.275 E
7.15<8352>97 144.2 S 2.75(Pa)-7.15 G(ddress)-2.75 E F1(Designated F)97
160.8 Q(orwarder \(DF\) State:)-.275 E F0 -.165(Fo)133 177.4 S 2.75(re)
.165 G(ach router interf)-2.75 E(ace:)-.11 E F1(Acting DF inf)133 194 Q
(ormation:)-.275 E F0 7.15<8344>158 210.6 S 2.75(FI)-7.15 G 2.75(PA)
-2.75 G(ddress)-2.75 E 7.15<8344>158 227.2 S 2.75(Fm)-7.15 G(etric)-2.75
E F1(Election inf)133 243.8 Q(ormation:)-.275 E F0 7.15<8345>158 260.4 S
(lection State)-7.15 E 7.15<8344>158 277 S 2.75(FE)-7.15 G(lection-T)
-2.75 E(imer \(DFT\))-.385 E 7.15<834f>158 293.6 S -.275(ff)-7.15 G(er)
.275 E(-Count \(OC\))-.22 E(Current best of)169 310.2 Q(fer:)-.275 E
7.15<8349>169 326.8 S 2.75(Pa)-7.15 G(ddress of best of)-2.75 E
(fering router)-.275 E 7.15<8342>169 343.4 S(est of)-7.15 E
(fering router metric)-.275 E(Designated F)72 360 Q(orw)-.165 E
(arder state is described in section 3.5.)-.11 E F1 2.75(3.1.3. Gr)72
389.6 R(oup State)-.198 E F0 -.165(Fo)72 406.2 S 2.75(re).165 G -.165
(ve)-3.025 G(ry group G a router k).165 E(eeps the follo)-.11 E
(wing state:)-.275 E(Group state:)122 422.8 Q -.165(Fo)147 439.4 S 2.75
(re).165 G(ach interf)-2.75 E(ace:)-.11 E F1(Local Membership:)147 456 Q
F0 7.15<8353>172 472.6 S(tate: One of {"NoInfo", "Include"})-7.15 E F1
(PIM J)147 489.2 Q(oin/Prune State:)-.165 E F0 7.15<8353>172 505.8 S
(tate: One of {"NoInfo" \(NI\), "Join" \(J\), "PrunePending" \(PP\)})
-7.15 E 7.15<8350>172 522.4 S(rune Pending T)-7.15 E(imer \(PPT\))-.385
E 7.15<834a>172 539 S(oin/Prune Expiry T)-7.15 E(imer \(ET\))-.385 E
(Not interf)122 555.6 Q(ace speci\214c:)-.11 E 7.15<8355>147 572.2 S
(pstream Join/Prune T)-7.15 E(imer \(JT\))-.385 E 7.15<834c>147 588.8 S
(ast RP Used)-7.15 E(Local membership is the result of the local member\
ship mechanism \(such as IGMP\) running on)72 605.4 Q(that interf)72
618.4 Q(ace. This information is used by the)-.11 E/F2 11/Courier@0 SF
(pim_include\(*,G\))2.75 E F0(macro described in section)2.75 E(3.1.4.)
72 631.4 Q(PIM Join/Prune state is the result of recei)72 648 Q
(ving PIM \(*,G\) Join/Prune messages on this interf)-.275 E(ace,)-.11 E
(and is speci\214ed in section 3.4.1. The state is used by the macros t\
hat calculate the outgoing)72 661 Q(interf)72 674 Q
(ace list in section 3.1.4, and in the)-.11 E F2(JoinDesired\(G\))2.75 E
F0(macro \(de\214ned in section 3.4.2\) that)2.75 E
(is used in deciding whether a Join\(*,G\) should be sent upstream.)72
687 Q(The upstream Join/Prune timer is used to send out periodic Join\(\
*,G\) messages, and to o)72 703.6 Q -.165(ve)-.165 G(rride).165 E
(Prune\(*,G\) messages from peers on an upstream LAN interf)72 716.6 Q
(ace.)-.11 E(Handle)72 769 Q(y/K)-.165 E(ouv)-.385 E(elas/Speakman/V)
-.165 E 154.91(icisano Section)-.66 F 2.75(3.1.3. [P)2.75 F(age 6])-.165
E EP
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/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(The last RP used must be stor\
ed because if the RP Set changes [9] then state must be torn do)72 85 Q
(wn)-.275 E(and reb)72 98 Q(uilt for groups whose RP changes.)-.22 E/F1
11/Times-Bold@0 SF 2.75(3.1.4. State)72 140.6 R(Summarization Macr)2.75
E(os)-.198 E F0(Using this state, we de\214ne the follo)72 157.2 Q
(wing "macro" de\214nitions which we will use in the descriptions)-.275
E(of the state machines and pseudocode in the follo)72 170.2 Q
(wing sections.)-.275 E/F2 11/Courier@0 SF(olist\(G\) =)72 199.8 Q
(RPF_interface\(RP\(G\)\) \(+\) joins\(G\) \(+\) pim_include\(G\))98.4
212.8 Q(RPF_interface\(RP\))72 242.4 Q F0(is the interf)2.75 E
(ace the MRIB indicates w)-.11 E(ould be used to route pack)-.11 E
(ets to)-.11 E(RP)72 255.4 Q 2.75(.T)-1.221 G
(he olist\(G\) is the list of interf)-2.75 E(aces on which pack)-.11 E
(ets to group G must be forw)-.11 E(arded.)-.11 E
(The macro pim_include\(G\) indicates the interf)72 272 Q
(aces to which traf)-.11 E(\214c might be forw)-.275 E(arded because)
-.11 E(of hosts that are local members on that interf)72 285 Q(ace.)-.11
E F2(pim_include\(G\) =)72 314.6 Q 6.6({a)98.4 327.6 S
(ll interfaces I such that:)-6.6 E(I_am_DF\(RP\(G\),I\) AND)111.6 340.6
Q(local_receiver_include\(G,I\) })13.2 E F0(The clause "I_am_DF\(RP)72
370.2 Q(,I\)" is TR)-1.221 E(UE if the router is in the)-.44 E F2(Win)
2.75 E F0(or)2.75 E F2(Backoff)2.75 E F0(states in the DF)2.75 E
(election state machine for interf)72 383.2 Q
(ace I \(described in section 3.5 \).)-.11 E(Otherwise it is F)5.5 E
(ALSE.)-.814 E(The clause "local_recei)72 399.8 Q -.165(ve)-.275 G
(r_include\(G,I\)" is true if the IGMP module or other local membership)
.165 E(mechanism has determined that there are local members on interf)
72 412.8 Q(ace I that desire to recei)-.11 E .33 -.165(ve t)-.275 H(raf)
.165 E<8c63>-.275 E(sent to group G.)72 425.8 Q
(The set "joins\(G\)" is the set of all interf)72 442.4 Q
(aces on which the router has recei)-.11 E -.165(ve)-.275 G 2.75(d\()
.165 G(*,G\) Joins:)-2.75 E F2(joins\(G\) =)72 459 Q 6.6({a)98.4 472 S
(ll interfaces I such that)-6.6 E(I_am_DF\(RP\(G\),I\) AND)111.6 485 Q
(DownstreamJPState\(G,I\) is either Joined or PrunePending })111.6 498 Q
F0(Do)72 514.6 Q(wnstreamJPState\(G,I\) is the state of the \214nite st\
ate machine in section 3.4.1.)-.275 E F2(RPF_DF\(RP\))72 531.2 Q F0(is \
the neighbor that Join messages must be sent to in order to reach the R\
P)2.75 E 2.75(.T)-1.221 G(his is)-2.75 E(the Designated-F)72 544.2 Q
(orw)-.165 E(arder on the)-.11 E F2(RPF_interface\(RP\))2.75 E F0(.)A F1
(3.2.)72 570.2 Q/F3 13/Times-Bold@0 SF(PIM Neighbor Disco)5.5 E -.13(ve)
-.13 G(ry).13 E F0(PIM routers e)72 586.8 Q(xchange PIM-Hello messages \
with their neighboring PIM routers. These messages)-.165 E
(are used to update the)72 599.8 Q F2(Neighbor State)2.75 E F0
(described in section 3.1. The procedures for)2.75 E
(generating and processing recei)72 612.8 Q -.165(ve)-.275 G 2.75(dH)
.165 G(ello messages as well as maintaining)-2.75 E F2(Neighbor State)
2.75 E F0(are speci\214ed in the PIM-SM [9] documentation.)72 625.8 Q(B\
idir PIM introduces the Bidir_Capable PIM-Hello option that MUST be inc\
luded in all Hello)72 642.4 Q(messages from a Bidir)72 655.4 Q
(-PIM capable router)-.22 E 5.5(.T)-.605 G(he Bidir_Capable option adv)
-5.5 E(ertises the router')-.165 E(s)-.605 E
(ability to participate in the Bidir)72 668.4 Q
(-PIM protocol. The format of the Bidir_Capable option is)-.22 E
(described in section 3.7.)72 681.4 Q(Handle)72 769 Q(y/K)-.165 E(ouv)
-.385 E(elas/Speakman/V)-.165 E 163.16(icisano Section)-.66 F 2.75
(3.2. [P)2.75 F(age 7])-.165 E EP
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BP
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/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(3.3.)72
85 Q/F2 13/Times-Bold@0 SF(Data P)5.5 E(ack)-.13 E(et F)-.13 E
(orwarding Rules)-.325 E F0 -.165(Fo)72 101.6 S 2.75(rg).165 G
(roups mapping to a gi)-2.75 E -.165(ve)-.275 G 2.75(nR).165 G 2.442
-1.221(P, t)-2.75 H(he follo)1.221 E
(wing responsibilities are uniquely assigned to the DF)-.275 E
(for that RP on each link:)72 114.6 Q 7.15<8354>72 131.2 S
(he DF is the only router that forw)-7.15 E(ards pack)-.11 E(ets tra)
-.11 E -.165(ve)-.22 G(ling do).165 E(wnstream onto the link.)-.275 E
7.15<8354>72 147.8 S
(he DF is the only router that picks-up upstream tra)-7.15 E -.165(ve)
-.22 G(ling pack).165 E(ets of)-.11 E 2.75(ft)-.275 G(he link to forw)
-2.75 E(ard)-.11 E(to)83 160.8 Q -.11(wa)-.275 G(rds the RP).11 E(.)
-1.221 E
(Non-DF routers on a link, that use that link as their RPF interf)72
177.4 Q(ace to reach the RP)-.11 E 2.75(,m)-1.221 G(ay perform)-2.75 E
(the follo)72 190.4 Q(wing forw)-.275 E
(arding actions for bidirectional groups:)-.11 E 7.15<8346>72 207 S(orw)
-7.315 E(ard pack)-.11 E(ets from the link to)-.11 E -.11(wa)-.275 G
(rds do).11 E(wnstream recei)-.275 E -.165(ve)-.275 G(rs.).165 E 7.15
<8346>72 223.6 S(orw)-7.315 E(ard pack)-.11 E(ets from do)-.11 E
(wnstream sources onto the link \(pro)-.275 E(vided the)-.165 E 2.75(ya)
-.165 G(re the DF for the)-2.75 E(do)83 236.6 Q
(wnstream link from which the pack)-.275 E(et w)-.11 E(as pick)-.11 E
(ed-up\).)-.11 E(The BIDIR-PIM pack)72 253.2 Q(et forw)-.11 E
(arding rules are de\214ned belo)-.11 E 2.75(wi)-.275 G 2.75(np)-2.75 G
(seudocode.)-2.75 E/F3 11/Courier@0 SF(iif)97 269.8 Q F0
(is the incoming interf)2.75 E(ace of the pack)-.11 E(et.)-.11 E F3(G)97
282.8 Q F0(is the destination address of the pack)2.75 E
(et \(group address\).)-.11 E F3(RP)97 295.8 Q F0
(is the address of the Rendezv)2.75 E(ous Point for this group.)-.22 E
(First we check to see whether the pack)72 312.4 Q
(et should be accepted based on TIB state and the interf)-.11 E(ace)-.11
E(that the pack)72 325.4 Q(et arri)-.11 E -.165(ve)-.275 G 2.75(do).165
G(n. A pack)-2.75 E(et is accepted if it arri)-.11 E -.165(ve)-.275 G
2.75(so).165 G 2.75(nt)-2.75 G(he RPF_interf)-2.75 E
(ace to reach the RP)-.11 E(\(do)72 338.4 Q(wnstream tra)-.275 E -.165
(ve)-.22 G(ling pack).165 E
(et\) or if the router is the DF on the interf)-.11 E(ace the pack)-.11
E(et arri)-.11 E -.165(ve)-.275 G(s).165 E(\(upstream tra)72 351.4 Q
-.165(ve)-.22 G(ling pack).165 E(et\).)-.11 E(If the pack)72 368 Q
(et should be forw)-.11 E(arded we b)-.11 E(uild an outgoing interf)-.22
E(ace list for the pack)-.11 E(et.)-.11 E(Finally we remo)72 384.6 Q .33
-.165(ve t)-.165 H(he incoming interf).165 E
(ace from the outgoing interf)-.11 E(ace list we')-.11 E .33 -.165(ve c)
-.55 H(reated, and if).165 E(the resulting outgoing interf)72 397.6 Q
(ace list is not empty)-.11 E 2.75(,w)-.715 G 2.75(ef)-2.75 G(orw)-2.75
E(ard the pack)-.11 E(et out of those interf)-.11 E(aces.)-.11 E
(On receipt on a data to G on interf)72 416.6 Q(ace iif:)-.11 E F3
(if\( iif == RPF_interface\(RP\) || I_am_DF\(RP,I\) \) {)78.6 442.6 Q
(oiflist = olist\(G\) \(-\) iif)98.4 455.6 Q
(forward packet on all interfaces in oiflist)98.4 468.6 Q(})78.6 481.6 Q
F0(Note: A major adv)72 517.2 Q(antage of using a Designated F)-.275 E
(orw)-.165 E(arder in BIDIR-PIM compared to PIM-SM)-.11 E(is that speci\
al treatment is no longer required for sources that are directly connec\
ted to a router)72 530.2 Q(.)-.605 E
(Data from such sources does not need to be dif)72 543.2 Q
(ferentiated from other multicast traf)-.275 E(\214c and will)-.275 E
(automatically be pick)72 556.2 Q(ed up by the DF)-.11 E 2.75(.T)-.88 G
(his remo)-2.75 E -.165(ve)-.165 G 2.75(st).165 G
(he need for performing a directly-)-2.75 E
(connected-source check for data to groups that do not ha)72 569.2 Q .33
-.165(ve ex)-.22 H(isting state.).165 E F1 2.75(3.3.1. Sour)72 598.8 R
(ce-Only Branches)-.198 E F0(Source-only branches of the distrib)72
615.4 Q(ution tree for a group G are branches which do not lead to an)
-.22 E(y)-.165 E(recei)72 628.4 Q -.165(ve)-.275 G(rs, b).165 E