Thanks AC for all your comment . Current version addresses your comment about providing reference to CRC 32 . I also added reference to base paper of HRW .
________________________________ From: Mankamana Mishra (mankamis) <manka...@cisco.com> Sent: Sunday, July 6, 2025 9:36:44 AM To: Acee Lindem <acee.i...@gmail.com> Cc: Routing ADs <rtg-...@ietf.org>; draft-ietf-bess-evpn-per-mcast-flow-df-elect...@ietf.org <draft-ietf-bess-evpn-per-mcast-flow-df-elect...@ietf.org>; bess@ietf.org <bess@ietf.org>; Routing Directorate <rtg-...@ietf.org> Subject: Re: Routing Directorate early review for draft-ietf-bess-evpn-per-mcast-flow-df-election-09 Sure, will add it in next revision. Did not find reference in base RFC too. I will discuss with you and upload the revision during IETF. From: Acee Lindem <acee.i...@gmail.com> Date: Saturday, July 5, 2025 at 1:15 PM To: Mankamana Mishra (mankamis) <manka...@cisco.com> Cc: Routing ADs <rtg-...@ietf.org>, draft-ietf-bess-evpn-per-mcast-flow-df-elect...@ietf.org <draft-ietf-bess-evpn-per-mcast-flow-df-elect...@ietf.org>, bess@ietf.org <bess@ietf.org>, Routing Directorate <rtg-...@ietf.org> Subject: Re: Routing Directorate early review for draft-ietf-bess-evpn-per-mcast-flow-df-election-09 Hi Mankamana, It looks good except I had also asked for a reference for the CRC-32 checksum - I don't see that in the current version. Thanks, Acee > On Jul 5, 2025, at 1:06 AM, Mankamana Mishra (mankamis) <manka...@cisco.com> > wrote: > > Hi Acee, Current revision of draft does address your comments. Will check > with you during IETF week if something more needs to be added. > Mankamana From: Acee Lindem <acee.i...@gmail.com> > Date: Wednesday, August 2, 2023 at 4:09 AM > To: Mankamana Mishra (mankamis) <manka...@cisco.com> > Cc: Routing ADs <rtg-...@ietf.org>, > draft-ietf-bess-evpn-per-mcast-flow-df-elect...@ietf.org > <draft-ietf-bess-evpn-per-mcast-flow-df-elect...@ietf.org>, bess@ietf.org > <bess@ietf.org>, Routing Directorate <rtg-...@ietf.org> > Subject: Re: Routing Directorate early review for > draft-ietf-bess-evpn-per-mcast-flow-df-election-09 > Hi Mankamana, > > > On Aug 1, 2023, at 17:44, Mankamana Mishra (mankamis) <manka...@cisco.com> > wrote: > Hi Acee, Thanks for reviewing and comment. While I make changes to existing > draft based on your comments, I had question on some of the comments > 1. Precisely explain the hashing algorithm in section 4.1 and 4.2. As > written, they subject to multiple interpretations. Provide a reference > to CRC_32() and expand acronyms on first use (e.g., MSB). > > 2. In addition to explaining the hashing algorithm, the document should > provide a discussion on why this hashing algorithm provides a good > distribiution of flows. > https://datatracker.ietf.org/doc/html/rfc8584#section-3 defines most of the > base HRW draft and its benefit . Do you expect it to be repeated in this > draft too ? This draft does not change the base HRW algorithm but adds flow > information as also an input parameter to calculate the weight ? > You shouldn’t include a formula in a document where the elements are not > explained, acronyms are not expanded, and references are not provided. > You could reference the RFC 8584 discussion of why the algorithm provides a > good distribution of traffic this reference should be accompanied with text > explaining how these benefits extend to individual multicast flows. > Thanks, > Acee > > > Please let me know if you want only reference to be given or content to be > copied here ? > Mankamana From: Acee Lindem <acee.i...@gmail.com> > Date: Friday, July 21, 2023 at 2:43 PM > To: Routing ADs <rtg-...@ietf.org>, > draft-ietf-bess-evpn-per-mcast-flow-df-elect...@ietf.org > <draft-ietf-bess-evpn-per-mcast-flow-df-elect...@ietf.org> > Cc: bess@ietf.org <bess@ietf.org>, Routing Directorate <rtg-...@ietf.org> > Subject: Routing Directorate early review for > draft-ietf-bess-evpn-per-mcast-flow-df-election-09 > Hello, > > I have been selected as the Routing Directorate reviewer for this draft. > The Routing Directorate seeks to review all routing or routing-related > drafts as they pass through IETF last call and IESG review, and > sometimes on special request. The purpose of the review is to provide > assistance to the Routing ADs. For more information about the Routing > Directorate, please see: > > http://trac.tools.ietf.org/area/rtg/trac/wiki/RtgDir > > Although these comments are primarily for the use of the Routing ADs, > it would be helpful if you could consider them along with any other > IETF Early Review/Last Call comments that you receive, and strive to > resolve them through discussion or by updating the draft. > > Document: draft-ietf-bess-evpn-per-mcast-flow-df-election-09 > Reviewer: Acee Lindem > Review Date: 07/20/2023 > IETF LC End Date: N/A > Intended Status: Standards Track > > Summary: > This document describes a per-multicast-flow DF election mechanism > which support per multicast flow load-balancing of the EVPN ES > forwarding amongst PEs in a redundancy group. While the document describes > a fairly straightforward function, it really needs some editing and never > should have been adopted as a WG document in this condition. Consequently, > I have entered a “Not Ready” disposition for the review. > > > Major Issues: > 1. Precisely explain the hashing algorithm in section 4.1 and 4.2. As > written, they subject to multiple interpretations. Provide a reference > to CRC_32() and expand acronyms on first use (e.g., MSB). > > 2. In addition to explaining the hashing algorithm, the document should > provide a discussion on why this hashing algorithm provides a good > distribiution of flows. > > 3. While this is a minor comment, it also pertains to the hashing > algorithm. To better distribute the flows, why not exclude the current > BUM DF from the list of PEs from which to choose a per-flow DF?? > > > Minor Issues: > > 1. Acronyms from RFC 7432 and RFC 8584 used without first expansion. > For example, none of the acronyms in the figures are defined. I'd > suggest adding a glossary with terms from other documents. > 2. The acronym "Es" is used for Ethernet Segment when ES is used in > other EVPN documents. > 3. Missing articles make the text unwieldy to read. > 4. Multiple problems with agreement of subject and verb. > 5. Define what is referred to by DFn. Presumably, this is the selected > PE in the redundancy group. > 5. Number 5 in section 5 doesn't make sense as written. I was trying to > fix it but it needs attention from the author. > 6. The abstract cannot include RFC references from the draft. However, > the RFCs may be referenced without the braces. > 7. The security considerations for RFC 8584 are also applicable. > Additionally, > you that you are going to be asked for a discussion of how the existing > security mechanisms apply to per-flow DF selection, so you might as well > provide it now. > > > Nits: See diff below. > > Thanks, > Acee > > > *** draft-ietf-bess-evpn-per-mcast-flow-df-election-09.txt.orig Wed Jul 19 > 11:43:37 2023 > --- draft-ietf-bess-evpn-per-mcast-flow-df-election-09.txt Wed Jul 19 > 12:21:57 2023 > *************** > *** 18,33 **** > > Abstract > > ! [RFC7432] describes mechanism to elect designated forwarder (DF) at > the granularity of (ESI, EVI) which is per VLAN (or per group of > VLANs in case of VLAN bundle or VLAN-aware bundle service). However, > the current level of granularity of per-VLAN is not adequate for some > ! applications.[RFC8584] improves base line DF election by introducing > ! HRW DF election. [RFC9251] introduces applicability of EVPN to > ! Multicast flows, routes to sync them and a default DF election. This > ! document is an extension to HRW base draft [RFC8584] and further > enhances HRW algorithm for the Multicast flows to do DF election at > ! the granularity of (ESI, VLAN, Mcast flow). > > Status of This Memo > > --- 18,33 ---- > > Abstract > > ! RFC7432 describes mechanism to elect a designated forwarder (DF) at > the granularity of (ESI, EVI) which is per VLAN (or per group of > VLANs in case of VLAN bundle or VLAN-aware bundle service). However, > the current level of granularity of per-VLAN is not adequate for some > ! applications. RFC8584 improves the base DF election by introducing > ! Highest Random Weigth (HRW) DF election. RFC9251 introduces > applicability of EVPN to > ! Multicast flows, routes to sync them, and a default DF election. This > ! document is an extension to HRW base draft and further > enhances HRW algorithm for the Multicast flows to do DF election at > ! the granularity of (ESI, VLAN, Multicast flow). > > Status of This Memo > > *************** > *** 91,104 **** > deployments as well as service provider access/aggregation networks. > [RFC7432] defines the role of a designated forwarder as the node in > the redundancy group that is responsible to forward Broadcast, > ! Unknown unicast, Multicast (BUM) traffic on that Ethernet Segment (CE > ! device or network) in All-Active multi-homing. > > The default DF election mechanism allows selecting a DF at the > granularity of (ES, VLAN) or (ES, VLAN bundle) for BUM traffic. > ! While [RFC8584] improve on the default DF election procedure, some > service provider residential applications require a finer > ! granularity, where whole multicast flows are delivered on a single > VLAN. > > > --- 91,104 ---- > deployments as well as service provider access/aggregation networks. > [RFC7432] defines the role of a designated forwarder as the node in > the redundancy group that is responsible to forward Broadcast, > ! Unknown unicast, Multicast (BUM) traffic on that Ethernet Segment > ! (Customer Edge (CE) device or network) in All-Active multi-homing. > > The default DF election mechanism allows selecting a DF at the > granularity of (ES, VLAN) or (ES, VLAN bundle) for BUM traffic. > ! While [RFC8584] improves on the default DF election procedure, some > service provider residential applications require a finer > ! granularity, where specific multicast flows are delivered on a single > VLAN. > > > *************** > *** 154,161 **** > > Consider the above topology, which shows a typical residential > deployment scenario, where multiple receivers are behind an all- > ! active multihoming segments. All of the multicast traffic is > ! provisioned on EVI-1. Assume PE-2 get elected as DF. According to > [RFC7432], PE-2 will be responsible for forwarding multicast traffic > to that Ethernet segment. > > --- 154,161 ---- > > Consider the above topology, which shows a typical residential > deployment scenario, where multiple receivers are behind an all- > ! active multihoming segment. All of the multicast traffic is > ! provisioned on EVI-1. Assume PE-2 gets elected as DF. According to > [RFC7432], PE-2 will be responsible for forwarding multicast traffic > to that Ethernet segment. > > *************** > *** 172,194 **** > > * Forcing sole data plane forwarding responsibility on PE-2 is a > limitation in the current DF election mechanism. The topology at > ! Figure 1 would always have only one of the PE to be elected as DF > ! irrespective of which current DF election mechanism is in use > ! defined in [RFC7432] or [RFC8584]. > > * The problem may also manifest itself in a different way. For > example, AC1 happens to use 80% of its available bandwidth to > forward unicast data. And now there is need to serve multicast > ! receivers where it would require more than 20% of AC1 bandwidth. > In this case, AC1 becomes oversubscribed and multicast traffic > drop would be observed even though there is already another link > ! (AC2) present in network which can be used more efficiently load > balance the multicast traffic. > > ! In this document, we propose an extension to the HRW base draft to > allow DF election at the granularity of (ESI, VLAN, Mcast flow) which > ! would allow multicast flows to be better distributed among redundancy > ! group PEs to share the load. > > 2. Terminology > > --- 172,194 ---- > > * Forcing sole data plane forwarding responsibility on PE-2 is a > limitation in the current DF election mechanism. The topology at > ! Figure 1 would always have only one of the PEs elected as DF > ! irrespective of which DF election mechanism (defined in [RFC7432] > ! or [RFC8584]) is in use. > > * The problem may also manifest itself in a different way. For > example, AC1 happens to use 80% of its available bandwidth to > forward unicast data. And now there is need to serve multicast > ! receivers where it would require more than 20% of AC1's bandwidth. > In this case, AC1 becomes oversubscribed and multicast traffic > drop would be observed even though there is already another link > ! (AC2) present in network which can be used more efficiently to load > balance the multicast traffic. > > ! In this document, we define an extension to the HRW base [RFC8584] to > allow DF election at the granularity of (ESI, VLAN, Mcast flow) which > ! would allow multicast flows to be better distributed among PEs in a > ! redundancy group to share the load. > > 2. Terminology > > *************** > *** 201,212 **** > > 3. The DF Election Extended Community > > ! [RFC8584] defines an extended community, which would be used for PEs > in redundancy group to reach a consensus as to which DF election > procedure is desired. A PE can notify other participating PEs in > ! redundancy group about its willingness to support Per multicast flow > base DF election capability by signaling a DF election extended > ! community along with Ethernet-Segment Route (Type-4). The current > proposal extends the existing extended community defined in > [RFC8584]. This draft defines new a DF type. > > --- 201,212 ---- > > 3. The DF Election Extended Community > > ! [RFC8584] defines an extended community, which is used by PEs > in redundancy group to reach a consensus as to which DF election > procedure is desired. A PE can notify other participating PEs in > ! the redundancy group as to its willingness to support per-multicast-flow > base DF election capability by signaling a DF election extended > ! community along with an Ethernet-Segment Route (Type-4). The current > proposal extends the existing extended community defined in > [RFC8584]. This draft defines new a DF type. > > *************** > *** 229,254 **** > - Type 5: HRW base per (*,G) multicast flow DF election > (explained in this document) > > ! * The [RFC8584] describes encoding of capabilities associated to the > ! DF election algorithm using Bitmap field. When these capabilities > bits are set along with the DF type-4 and type-5, they need to be > ! interpreted in context of this new DF type-4 and type-5. For > example, consider a scenario where all PEs in the same redundancy > ! group (same ES) can support both AC-DF, DF type-4 and DF type-5 > and receive such indications from the other PEs in the ES. In > this scenario, if a VLAN is not active in a PE, then the DF > election procedure on all PEs in the ES should factor that in and > ! exclude that PE in the DF election per multicast flow. > > ! * A PE SHOULD attach the DF election Extended Community to ES route > ! and Extended Community MUST be sent if the ES is locally > ! configured for DF type Per Multicast flow DF election. Only one > ! DF Election Extended community can be sent along with an ES route. > > * When a PE receives the ES Routes from all the other PEs for the > ES, it checks if all of other PEs have advertised their desire to > ! proceed by Per multicast flow DF election. If all peering PEs > ! have done so, it performs DF election based on Per multicast flow > procedure. But if: > > - There is at least one PE which advertised route-4 ( AD per ES > --- 229,254 ---- > - Type 5: HRW base per (*,G) multicast flow DF election > (explained in this document) > > ! * [RFC8584] describes encoding of capabilities associated to the > ! DF election algorithm using a Bitmap field. When these capabilities > bits are set along with the DF type-4 and type-5, they need to be > ! interpreted in context of the DF type-4 and type-5. For > example, consider a scenario where all PEs in the same redundancy > ! group (same ES) can support both AC-DF, DF type-4, and DF type-5 > and receive such indications from the other PEs in the ES. In > this scenario, if a VLAN is not active in a PE, then the DF > election procedure on all PEs in the ES should factor that in and > ! exclude that PE in the per-multicast-flow DF election. > > ! * A PE SHOULD attach the DF election Extended Community to an ES route > ! and the Extended Community MUST be sent if the ES is locally > ! configured for DF type Per-Multicast-flow DF election. Only one > ! DF Election Extended community can be sent with an ES route. > > * When a PE receives the ES Routes from all the other PEs for the > ES, it checks if all of other PEs have advertised their desire to > ! proceed with Per-multicast-flow DF election. If all peering PEs > ! have done so, it performs DF election based on the Per-multicast-flow > procedure. But if: > > - There is at least one PE which advertised route-4 ( AD per ES > *************** > *** 258,264 **** > - There is at least one PE signaling single active in the AD per > ES route > > ! it MUST be considered as an indication to support of only Default > DF election [RFC7432] and DF election procedure in [RFC7432] MUST > be used. > > --- 258,264 ---- > - There is at least one PE signaling single active in the AD per > ES route > > ! it MUST be considered as an indication to support of only the Default > DF election [RFC7432] and DF election procedure in [RFC7432] MUST > be used. > > *************** > *** 268,276 **** > repeat the description of HRW algorithm itself. > > EVPN PE does the discovery of redundancy groups based on [RFC7432]. > ! If redundancy group consists of N peering EVPN PE nodes, after the > ! discovery all PEs build an unordered list of IP address of all the > ! nodes in the redundancy group. The procedure defined in this draft > does not require the list of PEs to be ordered. Address [i] denotes > the IP address of the [i]th EVPN PE in redundancy group where (0 < i > <= N ). > --- 268,276 ---- > repeat the description of HRW algorithm itself. > > EVPN PE does the discovery of redundancy groups based on [RFC7432]. > ! If a redundancy group consists of N peering EVPN PE nodes, after the > ! discovery all PEs, build an unordered list of IP address of all the > ! nodes in the redundancy group. The procedure defined in this document > does not require the list of PEs to be ordered. Address [i] denotes > the IP address of the [i]th EVPN PE in redundancy group where (0 < i > <= N ). > *************** > *** 284,290 **** > > 4.1. DF election for IGMP (S,G) membership request > > ! The DF is the PE who has maximum weight for (S, G, V, Es) where > > * S - Multicast Source > > --- 284,290 ---- > > 4.1. DF election for IGMP (S,G) membership request > > ! The DF is the PE who has maximum weight for (S, G, V, ES) where > > * S - Multicast Source > > *************** > *** 292,309 **** > > * V - VLAN ID. > > ! * Es - Ethernet Segment Identifier > > Address[i] is address of the ith PE. The PEs IP address length does > not matter as only the lower-order 31 bits are modulo significant. > > 1. Weight > > ! * The weight of PE(i) to (S,G,VLAN ID, Es) is calculated by > ! function, weight (S,G,V, Es, Address(i)), where (0 < i <= N), > PE(i) is the PE at ordinal i. > > ! * Weight (S,G,V, Es, Address(i)) = (1103515245. > ((1103515245.Address(i) + 12345) XOR D(S,G,V,ESI))+12345) (mod > 2^31) > > --- 292,309 ---- > > * V - VLAN ID. > > ! * ES - Ethernet Segment Identifier > > Address[i] is address of the ith PE. The PEs IP address length does > not matter as only the lower-order 31 bits are modulo significant. > > 1. Weight > > ! * The weight of PE(i) to (S,G,VLAN ID, ES) is calculated by > ! function, weight (S,G,V, ES, Address(i)), where (0 < i <= N), > PE(i) is the PE at ordinal i. > > ! * Weight (S,G,V, ES, Address(i)) = (1103515245. > ((1103515245.Address(i) + 12345) XOR D(S,G,V,ESI))+12345) (mod > 2^31) > > *************** > *** 312,333 **** > > 2. Digest > > ! * D(S,G,V, Es) = CRC_32(S,G,V, Es) > > ! * Here D(S,G,V,Es) is the 31-bit digest (CRC_32 and discarding > ! the MSB) of the Source IP, Group IP, Vlan ID and Es. The CRC > MUST proceed as if the architecture is in network byte order > (big-endian). > > 4.2. DF election for IGMP (*,G) membership request > > ! The DF is the PE who has maximum weight for (G, V, Es) where > > * G - Multicast Group > > * V - VLAN ID. > > ! * Es - Ethernet Segment Identifier > > > > --- 312,333 ---- > > 2. Digest > > ! * D(S,G,V, ES) = CRC_32(S,G,V, ES) > > ! * Here D(S,G,V,ES) is the 31-bit digest (CRC_32 and discarding > ! the MSB) of the Source IP, Group IP, Vlan ID and ES. The CRC > MUST proceed as if the architecture is in network byte order > (big-endian). > > 4.2. DF election for IGMP (*,G) membership request > > ! The DF is the PE who has maximum weight for (G, V, ES) where > > * G - Multicast Group > > * V - VLAN ID. > > ! * ES - Ethernet Segment Identifier > > > > *************** > *** 343,353 **** > > 1. Weight > > ! * The weight of PE(i) to (G,VLAN ID, Es) is calculated by > ! function, weight (G,V, Es, Address(i)), where (0 < i <= N), > PE(i) is the PE at ordinal i. > > ! * Weight (G,V, Es, Address(i)) = (1103515245. > ((1103515245.Address(i) + 12345) XOR D(G,V,ESI))+12345) (mod > 2^31) > > --- 343,353 ---- > > 1. Weight > > ! * The weight of PE(i) to (G,VLAN ID, ES) is calculated by > ! function, weight (G,V, ES, Address(i)), where (0 < i <= N), > PE(i) is the PE at ordinal i. > > ! * Weight (G,V, ES, Address(i)) = (1103515245. > ((1103515245.Address(i) + 12345) XOR D(G,V,ESI))+12345) (mod > 2^31) > > *************** > *** 356,376 **** > > 2. Digest > > ! * D(G,V, Es) = CRC_32(G,V, Es) > > ! * Here D(G,V,Es) is the 31-bit digest (CRC_32 and discarding the > ! MSB) of the Group IP, Vlan ID and Es. The CRC MUST proceed as > if the architecture is in network byte order (big-endian). > > 4.3. Default DF election procedure > > ! Per multicast DF election procedure would be applicable only when > ! host behind Attachment Circuit (of the Es) start sending IGMP > ! membership requests. Membership requests are synced using procedure > ! defined in [RFC9251], and each of the PE in redundancy group can use > ! per flow DF election and create DF state per multicast flow. The HRW > DF election "Type 1" procedure defined in [RFC8584] MUST be used for > ! the Es DF election and SHOULD be performed on Es even before learning > multicast membership request state. This default election procedure > MUST be used at port level but will be overwritten by Per flow DF > election as and when new membership request state are learnt. > --- 356,376 ---- > > 2. Digest > > ! * D(G,V, ES) = CRC_32(G,V, Es) > > ! * Here D(G,V,ES) is the 31-bit digest (CRC_32 and discarding the > ! MSB) of the Group IP, Vlan ID and ES. The CRC MUST proceed as > if the architecture is in network byte order (big-endian). > > 4.3. Default DF election procedure > > ! Per-multicast-flow DF election procedure would be applicable only when > ! host behind the Attachment Circuit (of the ES) starts sending IGMP > ! membership requests. Membership requests are synced using the procedure > ! defined in [RFC9251], and each of the PEs in a redundancy group can use > ! per-multicast-flow DF election and create DF state per multicast flow. > The HRW > DF election "Type 1" procedure defined in [RFC8584] MUST be used for > ! the ES DF election and SHOULD be performed on ES even before learning > multicast membership request state. This default election procedure > MUST be used at port level but will be overwritten by Per flow DF > election as and when new membership request state are learnt. > *************** > *** 394,400 **** > Internet-Draft Per multicast flow Designated Forwarder July 2023 > > > ! Multicast Source > | > | > | > --- 394,400 ---- > Internet-Draft Per multicast flow Designated Forwarder July 2023 > > > ! Multicast Source > | > | > | > *************** > *** 436,446 **** > Route. This draft does not change any of this procedure, it > still uses the procedure defined in [RFC7432]. > > ! 2. Each of the PEs in redundancy group advertise Ethernet segment > ! route with extended community indicating their ability to > ! participate in per multicast flow DF election procedure. Since > ! Per multicast flow would not be applicable unless PE learns about > ! membership request from receiver, there is a need to have the > default DF election among PEs in redundancy group for BUM > > > --- 436,446 ---- > Route. This draft does not change any of this procedure, it > still uses the procedure defined in [RFC7432]. > > ! 2. Each of the PEs in the redundancy group advertise an Ethernet segment > ! route with an extended community indicating their ability to > ! participate in per-multicast-flow DF election procedure. Since > ! Per multicast flow would not be applicable unless the PE learns about > ! muilticast membership from a receiver, there is a need to have the > default DF election among PEs in redundancy group for BUM > > > *************** > *** 450,484 **** > Internet-Draft Per multicast flow Designated Forwarder July 2023 > > > ! traffic. Until multicast membership state are learnt, we use the > ! the DF election procedure in Section 4.3, namely HRW per (v,Es) > as defined in [RFC8584] . > > 3. When a receiver starts sending membership requests for (s1,g1), > ! where s1 is multicast source address and g1 is multicast group > address, CE-1 could hash membership request (IGMP join) to any of > the PEs in redundancy group. Let's consider it is hashed to PE- > 2. [RFC9251] defines a procedure to sync IGMP join state among > ! redundancy group of PEs. Now each of the PE would have > ! information about membership request (s1,g1) and each of them run > ! DF election procedure Section 4.1 to elect DF among participating > ! PEs in redundancy group. Consider PE-2 gets elected as DF for > ! multicast flow (s1,g1). > > 1. PE-1 forwarding state would be nDF for flow (s1,g1) and DF > for rest other BUM traffic. > > ! 2. PE-2 forwarding state would be DF for flow (s1,g1) and nDF > for rest other BUM traffic. > > 3. PE-3 forwarding state would be nDF for flow (s1,g1) and rest > other BUM traffic. > > ! 4. As and when new multicast membership request comes, same > ! procedure as above would continue. > > 5. If Section 3 has DF type 4, For membership request (S,G) it MUST > ! use Section 4.1 to elect DF among participating PEs. And > membership request (*,G) MUST use Section 4.2 to elect DF among > participating PEs. > > --- 450,485 ---- > Internet-Draft Per multicast flow Designated Forwarder July 2023 > > > ! traffic. Until multicast membership state is learnt, we use the > ! the DF election procedure in Section 4.3, namely HRW per (v,ES) > as defined in [RFC8584] . > > 3. When a receiver starts sending membership requests for (s1,g1), > ! where s1 is a multicast source address and g1 is a multicast group > address, CE-1 could hash membership request (IGMP join) to any of > the PEs in redundancy group. Let's consider it is hashed to PE- > 2. [RFC9251] defines a procedure to sync IGMP join state among > ! PEs in a redundancy group. Now each of the PE would have > ! information about the membership request (s1,g1) and each of them > would run > ! the DF election procedure (refer to Section 4.1)( to elect > ! a DF among participating PEs in the redundancy group. Consider PE-2 > ! gets elected as DF for multicast flow (s1,g1). > > 1. PE-1 forwarding state would be nDF for flow (s1,g1) and DF > for rest other BUM traffic. > > ! 2. PE-2 forwarding state would be the DF for flow (s1,g1) and nDF > for rest other BUM traffic. > > 3. PE-3 forwarding state would be nDF for flow (s1,g1) and rest > other BUM traffic. > > ! 4. When a new multicast membership request arrives, the same > ! procedure as above would used to selected a nDF for the > ! multicast flow. > > 5. If Section 3 has DF type 4, For membership request (S,G) it MUST > ! use Section 4.1 to elect a DF among participating PEs. And > membership request (*,G) MUST use Section 4.2 to elect DF among > participating PEs. > > *************** > *** 487,494 **** > There are multiple triggers which can cause DF re-election. Some of > the triggers could be > > ! 1. Local ES going down due to physical failure or configuration > ! change triggers DF re-election at peering PE. > > 2. Detection of new PE through ES route. > > --- 488,495 ---- > There are multiple triggers which can cause DF re-election. Some of > the triggers could be > > ! 1. Local ES going down due to physical failure or a configuration > ! change that triggers DF re-election at peering PE. > > 2. Detection of new PE through ES route. > > *************** > *** 509,515 **** > 6. Local configuration change of DF election Type and peering PE > consensus on new DF Type > > ! This document does not provide any new mechanism to handle DF re- > election procedure. It uses the existing mechanism defined in > [RFC7432]. Whenever either of the triggers occur, a DF re-election > would be done. and all of the flows would be redistributed among > --- 510,516 ---- > 6. Local configuration change of DF election Type and peering PE > consensus on new DF Type > > ! This document does not provide any new mechanisms to handle DF re- > election procedure. It uses the existing mechanism defined in > [RFC7432]. Whenever either of the triggers occur, a DF re-election > would be done. and all of the flows would be redistributed among
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