rfc9624v2.txt   rfc9624.txt 
Internet Engineering Task Force (IETF) Z. Zhang Internet Engineering Task Force (IETF) Z. Zhang
Request for Comments: 9624 T. Przygienda Request for Comments: 9624 T. Przygienda
Category: Standards Track Juniper Networks Category: Standards Track Juniper Networks
ISSN: 2070-1721 A. Sajassi ISSN: 2070-1721 A. Sajassi
Cisco Systems Cisco Systems
J. Rabadan J. Rabadan
Nokia Nokia
July 2024 August 2024
EVPN Broadcast, Unknown Unicast, or Multicast (BUM) Using Bit Index EVPN Broadcast, Unknown Unicast, or Multicast (BUM) Using Bit Index
Explicit Replication (BIER) Explicit Replication (BIER)
Abstract Abstract
This document specifies protocols and procedures for forwarding This document specifies protocols and procedures for forwarding
Broadcast, Unknown Unicast, or Multicast (BUM) traffic of Ethernet Broadcast, Unknown Unicast, or Multicast (BUM) traffic of Ethernet
VPNs (EVPNs) using Bit Index Explicit Replication (BIER). VPNs (EVPNs) using Bit Index Explicit Replication (BIER).
skipping to change at line 212 skipping to change at line 212
domain-id (see [RFC8279]). This indicates that packets sent domain-id (see [RFC8279]). This indicates that packets sent
on the PMSI will be sent on the specified BIER sub-domain. on the PMSI will be sent on the specified BIER sub-domain.
How that sub-domain is chosen is outside the scope of this How that sub-domain is chosen is outside the scope of this
document. document.
2. The second subfield is a two-octet field containing the BFR-id 2. The second subfield is a two-octet field containing the BFR-id
in the sub-domain identified in the first subfield of the in the sub-domain identified in the first subfield of the
router that is constructing the PTA. router that is constructing the PTA.
3. The third subfield is the BFR-Prefix (see [RFC8279]) of the 3. The third subfield is the BFR-Prefix (see [RFC8279]) of the
router (a BFIR) that is constructing the PTA. THE BRF-Prefix router (a BFIR) that is constructing the PTA. The BFR-Prefix
will either be a /32 IPv4 address or a /128 IPv6 address. will either be a /32 IPv4 address or a /128 IPv6 address.
Whether the address is IPv4 or IPv6 can be inferred from the Whether the address is IPv4 or IPv6 can be inferred from the
total length of the PTA. total length of the PTA.
The BFR-Prefix need not be the same IP address that is carried The BFR-Prefix need not be the same IP address that is carried
in any other field of the x-PMSI A-D route, even if the BFIR in any other field of the x-PMSI A-D route, even if the BFIR
is the originating router of the x-PMSI A-D route. is the originating router of the x-PMSI A-D route.
* MPLS Label. For EVPN-MPLS [RFC7432], this field contains an * MPLS Label. For EVPN-MPLS [RFC7432], this field contains an
upstream-assigned MPLS label. It is assigned by the BFIR. upstream-assigned MPLS label. It is assigned by the BFIR.
skipping to change at line 256 skipping to change at line 256
2.1. IP-Based Tunnel and BIER PHP 2.1. IP-Based Tunnel and BIER PHP
When VXLAN/NVGRE/GENEVE is used for EVPN, by default, the outer IP When VXLAN/NVGRE/GENEVE is used for EVPN, by default, the outer IP
header (and UDP header in the case of VXLAN/GENEVE) is not included header (and UDP header in the case of VXLAN/GENEVE) is not included
in the BIER payload, except when it is known a priori that BIER in the BIER payload, except when it is known a priori that BIER
Penultimate Hop Popping (PHP) [BIER-PHP] is used in the BIER domain Penultimate Hop Popping (PHP) [BIER-PHP] is used in the BIER domain
and the encapsulation (after the BIER header is popped) between the and the encapsulation (after the BIER header is popped) between the
BIER Penultimate Hop and the egress PE does not have a way to BIER Penultimate Hop and the egress PE does not have a way to
indicate the next header is VXLAN/NVGRE/GENEVE. In that case, the indicate the next header is VXLAN/NVGRE/GENEVE. In that case, the
full VXLAN/NVGRE/GENEVE encapsulation MUST be used. In the outer IP full VXLAN/NVGRE/GENEVE encapsulation MUST be used. In the outer IP
header, a well-known IP multicast address (to be assigned by IANA) is header, a well-known IP multicast address (224.0.0.122 in the case of
used as the destination address, and the egress PEs MUST be set up to IPv4 or FF02:0:0:0:0:0:0:14 in the case of IPv6) is used as the
receive and process packets addressed to the destination address. destination address, and the egress PEs MUST be set up to receive and
The address is used for all BDs, and the inner VXLAN/NVGRE/GENEVE process packets addressed to the destination address. The address is
header will be used to identify BDs. used for all BDs, and the inner VXLAN/NVGRE/GENEVE header will be
used to identify BDs.
2.2. Explicit Tracking 2.2. Explicit Tracking
When using BIER to transport an EVPN BUM data packet through a BIER When using BIER to transport an EVPN BUM data packet through a BIER
domain, an ingress PE functions as a BFIR (see [RFC8279]). The BFIR domain, an ingress PE functions as a BFIR (see [RFC8279]). The BFIR
must determine the set of BFERs to which the packet needs to be must determine the set of BFERs to which the packet needs to be
delivered. This can be done in either of two ways as described in delivered. This can be done in either of two ways as described in
the following two sections. the following two sections.
2.2.1. Using IMET/SMET Routes 2.2.1. Using IMET/SMET Routes
skipping to change at line 463 skipping to change at line 464
then pushed onto the packet's label stack for EVPN-MPLS. For EVPN- then pushed onto the packet's label stack for EVPN-MPLS. For EVPN-
VXLAN/NVGRE/GENEVE, a VXLAN/NVGRE/GENEVE header is prepended to the VXLAN/NVGRE/GENEVE, a VXLAN/NVGRE/GENEVE header is prepended to the
packet with the VNI/VSID set to the value in the PTA's Label field, packet with the VNI/VSID set to the value in the PTA's Label field,
and then an IP/UDP header is prepended if needed (e.g., for PHP and then an IP/UDP header is prepended if needed (e.g., for PHP
purposes). purposes).
Then, the packet is encapsulated in a BIER header and forwarded Then, the packet is encapsulated in a BIER header and forwarded
according to the procedures of [RFC8279] and [RFC8296]. according to the procedures of [RFC8279] and [RFC8296].
Specifically, see "Imposing and Processing the BIER Encapsulation" Specifically, see "Imposing and Processing the BIER Encapsulation"
(Section 3 of [RFC8296]). The Proto field in the BIER header is set (Section 3 of [RFC8296]). The Proto field in the BIER header is set
to 2 in the case of EVPN-MPLS, a value to be assigned in the case of to 2 in the case of EVPN-MPLS, 7/8/9 in the case of EVPN-VXLAN/NVGRE/
EVPN-VXLAN/NVGRE/GENEVE (Section 5) when an IP header is not used, or GENEVE (Section 5) when an IP header is not used, or 4/6 if an IP
4/6 if an IP header is used for EVPN-VXLAN/NVGRE/GENEVE. header is used for EVPN-VXLAN/NVGRE/GENEVE.
To create the proper BIER header for a given packet, the BFIR must To create the proper BIER header for a given packet, the BFIR must
know all the BFERs that need to receive that packet. This is know all the BFERs that need to receive that packet. This is
determined from the set of leaf-tracking routes. determined from the set of leaf-tracking routes.
4.1.2. At a BFIR That Is a P-Tunnel Segmentation Point 4.1.2. At a BFIR That Is a P-Tunnel Segmentation Point
In this case, the encapsulation for the upstream segment of the In this case, the encapsulation for the upstream segment of the
P-tunnel includes (among other things) a label that identifies the P-tunnel includes (among other things) a label that identifies the
x-PMSI or IMET A-D route that is the match for reception on the x-PMSI or IMET A-D route that is the match for reception on the
 End of changes. 4 change blocks. 
10 lines changed or deleted 11 lines changed or added

This html diff was produced by rfcdiff 1.48.