< draft-ietf-bier-use-cases-10.txt   draft-ietf-bier-use-cases-11.txt >
Network Working Group N. Kumar Network Working Group N. Kumar
Internet-Draft R. Asati Internet-Draft R. Asati
Intended status: Informational Cisco Intended status: Informational Cisco
Expires: February 5, 2020 M. Chen Expires: September 5, 2020 M. Chen
X. Xu X. Xu
Huawei Huawei
A. Dolganow A. Dolganow
Nokia Nokia
T. Przygienda T. Przygienda
Juniper Networks Juniper Networks
A. Gulko A. Gulko
Thomson Reuters Thomson Reuters
D. Robinson D. Robinson
id3as-company Ltd id3as-company Ltd
V. Arya V. Arya
DirecTV Inc DirecTV Inc
C. Bestler C. Bestler
Nexenta Nexenta
August 4, 2019 March 4, 2020
BIER Use Cases BIER Use Cases
draft-ietf-bier-use-cases-10.txt draft-ietf-bier-use-cases-11.txt
Abstract Abstract
Bit Index Explicit Replication (BIER) is an architecture that Bit Index Explicit Replication (BIER) is an architecture that
provides optimal multicast forwarding through a "BIER domain" without provides optimal multicast forwarding through a "BIER domain" without
requiring intermediate routers to maintain any multicast related per- requiring intermediate routers to maintain any multicast related per-
flow state. BIER also does not require any explicit tree-building flow state. BIER also does not require any explicit tree-building
protocol for its operation. A multicast data packet enters a BIER protocol for its operation. A multicast data packet enters a BIER
domain at a "Bit-Forwarding Ingress Router" (BFIR), and leaves the domain at a "Bit-Forwarding Ingress Router" (BFIR), and leaves the
BIER domain at one or more "Bit-Forwarding Egress Routers" (BFERs). BIER domain at one or more "Bit-Forwarding Egress Routers" (BFERs).
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This Internet-Draft will expire on February 5, 2020. This Internet-Draft will expire on September 5, 2020.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Specification of Requirements . . . . . . . . . . . . . . . . 3 2. Specification of Requirements . . . . . . . . . . . . . . . . 3
3. BIER Use Cases . . . . . . . . . . . . . . . . . . . . . . . 3 3. BIER Use Cases . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Multicast in L3VPN Networks . . . . . . . . . . . . . . . 3 3.1. Multicast in L3VPN Networks . . . . . . . . . . . . . . . 3
3.2. BUM in EVPN . . . . . . . . . . . . . . . . . . . . . . . 4 3.2. Broadcast, Unknown unicast and Multicast (BUM) in EVPN . 4
3.3. IPTV and OTT Services . . . . . . . . . . . . . . . . . . 5 3.3. IPTV and OTT Services . . . . . . . . . . . . . . . . . . 5
3.4. Multi-Service, Converged L3VPN Network . . . . . . . . . 6 3.4. Multi-Service, Converged L3VPN Network . . . . . . . . . 6
3.5. Control-Plane Simplification and SDN-Controlled Networks 7 3.5. Control-Plane Simplification and SDN-Controlled Networks 7
3.6. Data Center Virtualization/Overlay . . . . . . . . . . . 7 3.6. Data Center Virtualization/Overlay . . . . . . . . . . . 8
3.7. Financial Services . . . . . . . . . . . . . . . . . . . 8 3.7. Financial Services . . . . . . . . . . . . . . . . . . . 8
3.8. 4K Broadcast Video Services . . . . . . . . . . . . . . . 9 3.8. 4K Broadcast Video Services . . . . . . . . . . . . . . . 9
3.9. Distributed Storage Cluster . . . . . . . . . . . . . . . 10 3.9. Distributed Storage Cluster . . . . . . . . . . . . . . . 10
3.10. HTTP-Level Multicast . . . . . . . . . . . . . . . . . . 11 3.10. Hyper Text Transfer Protocol (HTTP) Level Multicast . . . 11
4. Security Considerations . . . . . . . . . . . . . . . . . . . 13 4. Security Considerations . . . . . . . . . . . . . . . . . . . 13
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13
7. Contributing Authors . . . . . . . . . . . . . . . . . . . . 13 7. Contributing Authors . . . . . . . . . . . . . . . . . . . . 14
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
8.1. Normative References . . . . . . . . . . . . . . . . . . 13 8.1. Normative References . . . . . . . . . . . . . . . . . . 14
8.2. Informative References . . . . . . . . . . . . . . . . . 14 8.2. Informative References . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction 1. Introduction
Bit Index Explicit Replication (BIER) [RFC8279] is an architecture Bit Index Explicit Replication (BIER) [RFC8279] is an architecture
that provides optimal multicast forwarding through a "BIER domain" that provides optimal multicast forwarding through a "BIER domain"
without requiring intermediate routers to maintain any multicast without requiring intermediate routers to maintain any multicast
related per-flow state. BIER also does not require any explicit related per-flow state. BIER also does not require any explicit
tree-building protocol for its operation. A multicast data packet tree-building protocol for its operation. A multicast data packet
enters a BIER domain at a "Bit-Forwarding Ingress Router" (BFIR), and enters a BIER domain at a "Bit-Forwarding Ingress Router" (BFIR), and
leaves the BIER domain at one or more "Bit-Forwarding Egress Routers" leaves the BIER domain at one or more "Bit-Forwarding Egress Routers"
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protocol that sets up tree on demand based on users joining a protocol that sets up tree on demand based on users joining a
multicast flow. In that sense, BIER is potentially applicable to multicast flow. In that sense, BIER is potentially applicable to
many services where multicast is used and not limited to the examples many services where multicast is used and not limited to the examples
described in this draft. In this document we are describing a few described in this draft. In this document we are describing a few
use cases where BIER could provide benefit over using existing use cases where BIER could provide benefit over using existing
mechanisms. mechanisms.
2. Specification of Requirements 2. Specification of Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
document are to be interpreted as described in [RFC2119]. "OPTIONAL" in this document are to be interpreted as described in RFC
2119 [RFC2119] RFC 8174 [RFC8174] when and only when, they appear in
all capitals, as shown here.
3. BIER Use Cases 3. BIER Use Cases
3.1. Multicast in L3VPN Networks 3.1. Multicast in L3VPN Networks
The Multicast L3VPN architecture [RFC6513] describes many different The Multicast L3VPN architecture [RFC6513] describes many different
profiles in order to transport L3 multicast across a provider's profiles in order to transport L3 multicast across a provider's
network. Each profile has its own different tradeoffs (see section network. Each profile has its own different tradeoffs (see section
2.1 [RFC6513]). When using "Multidirectional Inclusive" "Provider 2.1 [RFC6513]). When using "Multidirectional Inclusive" "Provider
Multicast Service Interface" (MI-PMSI) an efficient tree is built per Multicast Service Interface" (MI-PMSI) an efficient tree is built per
VPN, but causes flooding of egress PE's that are part of the VPN, but VPN, but causes flooding of egress PEs that are part of the VPN, but
have not joined a particular C-multicast flow. This problem can be have not joined a particular C-multicast flow. This problem can be
solved with the "Selective" PMSI (S-PMSI) by building a special tree solved with the "Selective" PMSI (S-PMSI) by building a special tree
for only those PEs that have joined the C-multicast flow for that for only those PEs that have joined the C-multicast flow for that
specific VPN. The more S-PMSI's, the less bandwidth is wasted due to specific VPN. The more S-PMSI's, the less bandwidth is wasted due to
flooding, but causes more state to be created in the provider's flooding, but causes more state to be created in the provider's
network. This is a typical problem network operators are faced with network. This is a typical problem network operators are faced with
by finding the right balance between the amount of state carried in by finding the right balance between the amount of state carried in
the network and how much flooding (waste of bandwidth) is acceptable. the network and how much flooding (waste of bandwidth) is acceptable.
Some of the complexity with L3VPN's comes due to providing different Some of the complexity with L3VPN's comes due to providing different
profiles to accommodate these trade-offs. profiles to accommodate these trade-offs.
With BIER there is no trade-off between State and Flooding. Since With BIER there is no trade-off between State and Flooding. Since
the receiver information is explicitly carried within the packet, the receiver information is explicitly carried within the packet,
there is no need to build S-PMSI's to deliver multicast to a sub-set there is no need to build S-PMSI's to deliver multicast to a sub-set
of the VPN egress PE's. Due to that behaviour, there is no need for of the VPN egress PEs. Due to that behaviour, there is no need for
S-PMSI's. S-PMSI's.
MI-PMSI's and S-PMSI's are also used to provide the VPN context to MI-PMSI's and S-PMSI's are also used to provide the VPN context to
the egress PE router that receives the multicast packet. Also, in the egress PE router that receives the multicast packet. Also, in
some MVPN profiles it is also required to know which Ingress PE some MVPN profiles it is also required to know which Ingress PE
forwarded the packet. Based on the PMSI the packet is received from, forwarded the packet. Based on the PMSI the packet is received from,
the target VPN is determined. This also means there is a requirement the target VPN is determined. This also means there is a requirement
to have at least a PMSI per VPN or per VPN/ingress PE. This means to have at least a PMSI per VPN or per VPN/ingress PE. This means
the amount of state created in the network is proportional to the VPN the amount of state created in the network is proportional to the VPN
and ingress PEs. Creating PMSI state per VPN can be prevented by and ingress PEs. Creating PMSI state per VPN can be prevented by
applying the procedures as documented in [RFC5331]. This however has applying the procedures as documented in [RFC5331]. This however has
not been very much adopted/implemented due to the excessive flooding not been very much adopted/implemented due to the excessive flooding
it would cause to egress PEs since *all* VPN multicast packets are it would cause to egress PEs since *all* VPN multicast packets are
forwarded to *all* PEs that have one or more VPNs attached to it. forwarded to *all* PEs that have one or more VPNs attached to it.
With BIER, the destination PEs are identified in the multicast With BIER, the destination PEs are identified in the multicast
packet, so there is no flooding concern when implementing [RFC5331]. packet, so there is no flooding concern when implementing [RFC5331].
For that reason there is no need to create multiple BIER domains per For that reason there is no need to create multiple BIER domains per
VPN, the VPN context can be carry in the multicast packet using the VPN, the VPN context can be carry in the multicast packet using the
procedures as defined in [RFC5331]. Also see [I-D.ietf-bier-mvpn] procedures as defined in [RFC5331]. Also see [RFC8556] for more
for more information. information.
With BIER only a few MVPN profiles will remain relevant, simplifying With BIER only a few MVPN profiles will remain relevant, simplifying
the operational cost and making it easier to be interoperable among the operational cost and making it easier to be interoperable among
different vendors. different vendors.
3.2. BUM in EVPN 3.2. Broadcast, Unknown unicast and Multicast (BUM) in EVPN
The current widespread adoption of L2VPN services [RFC4664], The current widespread adoption of L2VPN services [RFC4664],
especially the upcoming EVPN solution [RFC7432] which transgresses especially the upcoming EVPN solution [RFC7432] which transgresses
many limitations of VPLS, introduces the need for an efficient many limitations of Virtual Private LAN Service (VPLS), introduces
mechanism to replicate broadcast, unknown and multicast (BUM) traffic the need for an efficient mechanism to replicate broadcast, unknown
towards the PEs that participate in the same EVPN instances (EVIs). unicast and multicast (BUM) traffic towards the PEs that participate
As simplest deployable mechanism, ingress replication is used but in the same EVPN instances (EVIs). As simplest deployable mechanism,
poses accordingly a high burden on the ingress node as well as ingress replication is used but poses accordingly a high burden on
saturating the underlying links with many copies of the same frame the ingress node as well as saturating the underlying links with many
headed to different PEs. Fortunately enough, EVPN signals internally copies of the same frame headed to different PEs. Fortunately
PMSI attribute [RFC6513] to establish transport for BUM frames and enough, EVPN signals internally PMSI attribute [RFC6513] to establish
with that allows to deploy a plethora of multicast replication transport for BUM frames and with that allows to deploy a plethora of
services that the underlying network layer can provide. It is multicast replication services that the underlying network layer can
therefore relatively simple to deploy BIER P-Tunnels for EVPN and provide. It is therefore relatively simple to deploy BIER P-Tunnels
with that distribute BUM traffic without creating P-router states in for EVPN and with that distribute BUM traffic without creating
the core that are required by PIM, mLDP or comparable solutions. P-router states in the core that are required by Protocol Independent
Multicast (PIM), Multipoint LDP (mLDP) or comparable solutions.
Specifically, the same I-PMSI attribute suggested for mVPN can be Specifically, the same I-PMSI attribute suggested for mVPN can be
used easily in EVPN, and given that EVPN can multiplex and used easily in EVPN, and given that EVPN can multiplex and
disassociate BUM frames on p2mp and mp2mp trees using upstream disassociate BUM frames on p2mp and mp2mp trees using upstream
assigned labels, BIER P-Tunnel will support BUM flooding for any assigned labels, BIER P-Tunnel will support BUM flooding for any
number of EVIs over a single sub-domain for maximum scalability but number of EVIs over a single sub-domain for maximum scalability but
allow at the other extreme of the spectrum to use a single BIER sub- allow at the other extreme of the spectrum to use a single BIER sub-
domain per EVI if such a deployment is necessary. domain per EVI if such a deployment is necessary.
Multiplexing EVIs onto the same PMSI forces the PMSI to span more Multiplexing EVIs onto the same PMSI forces the PMSI to span more
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meet large audience demand. Their applications are not limited to meet large audience demand. Their applications are not limited to
audio and video delivery, but may include static and dynamic web audio and video delivery, but may include static and dynamic web
content, or optimized delivery for Massive Multiplayer Gaming and content, or optimized delivery for Massive Multiplayer Gaming and
similar. Most publishers will use a CDN for public Internet similar. Most publishers will use a CDN for public Internet
delivery, and some publishers will use a CDN internally within their delivery, and some publishers will use a CDN internally within their
IPTV networks to resolve layer 4 complexity. IPTV networks to resolve layer 4 complexity.
In a typical IPTV environment the egress routers connecting to the In a typical IPTV environment the egress routers connecting to the
receivers will build the tree towards the ingress router connecting receivers will build the tree towards the ingress router connecting
to the IPTV servers. The egress routers would rely on IGMP/MLD to the IPTV servers. The egress routers would rely on IGMP/MLD
(static or dynamic) to learn about the receiver's interest in one or (static or dynamic) to learn about the receivers interest in one or
more multicast groups/channels. Interestingly, BIER could allow more multicast groups/channels. Interestingly, BIER could allow
provisioning any new multicast group/channel by only modifying the provisioning any new multicast group/channel by only modifying the
channel mapping on ingress routers. This is deemed beneficial for channel mapping on ingress routers. This is deemed beneficial for
the linear IPTV video broadcasting in which all receivers behind all the linear IPTV video broadcasting in which all receivers behind all
egress PE routers would receive the IPTV video traffic. egress PE routers would receive the IPTV video traffic.
With BIER in an IPTV environment, there is no need for tree building With BIER in an IPTV environment, there is no need for tree building
from egress to ingress. Further, any addition of new channels or new from egress to ingress. Further, any addition of new channels or new
egress routers can be directly controlled from the ingress router. egress routers can be directly controlled from the ingress router.
When a new channel is included, the multicast group is mapped to a When a new channel is included, the multicast group is mapped to a
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start sending the new channel and deliver it to all egress routers. start sending the new channel and deliver it to all egress routers.
As it can be observed, there is no need for static IGMP provisioning As it can be observed, there is no need for static IGMP provisioning
in each egress router whenever a new group/channel is added. in each egress router whenever a new group/channel is added.
Instead, it can be controlled from ingress router itself by Instead, it can be controlled from ingress router itself by
configuring the new group to bit mask mapping on ingress router. configuring the new group to bit mask mapping on ingress router.
With BIER in OTT environment, the edge routers in CDN domain With BIER in OTT environment, the edge routers in CDN domain
terminating the OTT user session connect to the ingress BIER routers terminating the OTT user session connect to the ingress BIER routers
connecting content provider domains or a local cache server and connecting content provider domains or a local cache server and
leverage the scalability benefit that BIER could provide. This may leverage the scalability benefit that BIER could provide. This may
rely on MBGP interoperation (or similar) between the egress of one rely on Multi-Protocol BGP (MP-BGP) interoperation (or similar)
domain and the ingress of the next domain, or some other SDN control between the egress of one domain and the ingress of the next domain,
plane may prove a more effective and simpler way to deploy BIER. For or some other SDN control plane may prove a more effective and
a single CDN operator this could be well managed in the layer 4 simpler way to deploy BIER. For a single CDN operator this could be
applications that they provide and it may be that the initial well managed in the layer 4 applications that they provide and it may
receiver in a remote domain is actually an application operated by be that the initial receiver in a remote domain is actually an
the CDN which in turn acts as a source for the ingress BIER router in application operated by the CDN which in turn acts as a source for
that remote domain, and by doing so keeps the BIER domains discrete. the ingress BIER router in that remote domain, and by doing so keeps
the BIER domains discrete.
3.4. Multi-Service, Converged L3VPN Network 3.4. Multi-Service, Converged L3VPN Network
Increasingly operators deploy single networks for multiple services. Increasingly operators deploy single networks for multiple services.
For example a single metro core network could be deployed to provide For example a single metro core network could be deployed to provide
residential IPTV retail service, residential IPTV wholesale service, residential IPTV retail service, residential IPTV wholesale service,
and business L3VPN service with multicast. It may often be desired and business L3VPN service with multicast. It may often be desired
by an operator to use a single architecture to deliver multicast for by an operator to use a single architecture to deliver multicast for
all of those services. In some cases, governing regulations may all of those services. In some cases, governing regulations may
additionally require same service capabilities for both wholesale and additionally require same service capabilities for both wholesale and
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Increasingly operators deploy single networks for multiple services. Increasingly operators deploy single networks for multiple services.
For example a single metro core network could be deployed to provide For example a single metro core network could be deployed to provide
residential IPTV retail service, residential IPTV wholesale service, residential IPTV retail service, residential IPTV wholesale service,
and business L3VPN service with multicast. It may often be desired and business L3VPN service with multicast. It may often be desired
by an operator to use a single architecture to deliver multicast for by an operator to use a single architecture to deliver multicast for
all of those services. In some cases, governing regulations may all of those services. In some cases, governing regulations may
additionally require same service capabilities for both wholesale and additionally require same service capabilities for both wholesale and
retail multicast services. To meet those requirements, some retail multicast services. To meet those requirements, some
operators use the multicast architecture as defined in [RFC5331]. operators use the multicast architecture as defined in [RFC5331].
However, the need to support many L3VPNs, with some of those L3VPNs However, the need to support many L3VPNs, with some of those L3VPNs
scaling to hundreds of egress PE's and thousands of C-multicast scaling to hundreds of egress PEs and thousands of C-multicast flows,
flows, make scaling/efficiency issues defined in earlier sections of make scaling/efficiency issues defined in earlier sections of this
this document even more prevalent. Additionally support for tens of document even more prevalent. Additionally support for tens of
millions of BGP multicast A-D and join routes alone could be required millions of BGP multicast A-D and join routes alone could be required
in such networks with all of the consequences that such a scale in such networks with all of the consequences that such a scale
brings. brings.
With BIER, again there is no need of tree building from egress to With BIER, again there is no need of tree building from egress to
ingress for each L3VPN or individual or group of c-multicast flows. ingress for each L3VPN or individual or group of c-multicast flows.
As described earlier, any addition of a new IPTV channel or new As described earlier, any addition of a new IPTV channel or new
egress router can be directly controlled from ingress router and egress router can be directly controlled from ingress router and
there is no flooding concern when implementing [RFC5331]. there is no flooding concern when implementing [RFC5331].
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3.6. Data Center Virtualization/Overlay 3.6. Data Center Virtualization/Overlay
Virtual eXtensible Local Area Network (VXLAN) [RFC7348] is a kind of Virtual eXtensible Local Area Network (VXLAN) [RFC7348] is a kind of
network virtualization overlay technology which is intended for network virtualization overlay technology which is intended for
multi-tenancy data center networks. To emulate a layer 2 flooding multi-tenancy data center networks. To emulate a layer 2 flooding
domain across the layer 3 underlay, it requires a 1:1 or n:1 mapping domain across the layer 3 underlay, it requires a 1:1 or n:1 mapping
between the VXLAN Virtual Network Instance (VNI) and the between the VXLAN Virtual Network Instance (VNI) and the
corresponding IP multicast group. In other words, it requires corresponding IP multicast group. In other words, it requires
enabling the multicast capability in the underlay. For instance, it enabling the multicast capability in the underlay. For instance, it
requires enabling PIM-SM [RFC4601] or PIM-BIDIR [RFC5015] multicast requires enabling PIM-SM [RFC7761] or PIM-BIDIR [RFC5015] multicast
routing protocol in the underlay. VXLAN is designed to support 16M routing protocol in the underlay. VXLAN is designed to support 16M
VNIs at maximum. In the mapping ratio of 1:1, it would require 16M VNIs at maximum. In the mapping ratio of 1:1, it would require 16M
multicast groups in the underlay which would become a significant multicast groups in the underlay which would become a significant
challenge to both the control plane and the data plane of the data challenge to both the control plane and the data plane of the data
center switches. In the mapping ratio of n:1, it would result in center switches. In the mapping ratio of n:1, it would result in
inefficiency bandwidth utilization which is not optimal in data inefficiency bandwidth utilization which is not optimal in data
center networks. More importantly, it is recognized by many data center networks. More importantly, it is recognized by many data
center operators as an undesireable burden to run multicast in data center operators as an undesireable burden to run multicast in data
center networks from the perspective of network operation and center networks from the perspective of network operation and
maintenance. As a result, many VXLAN implementations claim to maintenance. As a result, many VXLAN implementations claim to
support the ingress replication capability since ingress replication support the ingress replication capability since ingress replication
eliminates the burden of running multicast in the underlay. Ingress eliminates the burden of running multicast in the underlay. Ingress
replication is an acceptable choice in small-sized networks where the replication is an acceptable choice in small-sized networks where the
average number of receivers per multicast flow is not too large. average number of receivers per multicast flow is not too large.
However, in multi-tenant data center networks, especially those in However, in multi-tenant data center networks, especially those in
which the NVE functionality is enabled on a large number of physical which the Network Virtualization Edge (NVE)functionality is enabled
servers, the average number of NVEs per VN instance would be very on a large number of physical servers, the average number of NVEs per
large. As a result, the ingress replication scheme would result in a VN instance would be very large. As a result, the ingress
serious bandwidth waste in the underlay and a significant replication replication scheme would result in a serious bandwidth waste in the
burden on ingress NVEs. underlay and a significant replication burden on ingress NVEs.
With BIER, there is no need for maintaining that huge amount of With BIER, there is no need for maintaining that huge amount of
multicast state in the underlay anymore while the delivery efficiency multicast state in the underlay anymore while the delivery efficiency
of overlay BUM traffic is the same as if any kind of stateful of overlay BUM traffic is the same as if any kind of stateful
multicast protocols such as PIM-SM or PIM-BIDIR is enabled in the multicast protocols such as PIM-SM or PIM-BIDIR is enabled in the
underlay. underlay.
3.7. Financial Services 3.7. Financial Services
Financial services extensively rely on IP multicast to deliver stock Financial services extensively rely on IP multicast to deliver stock
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In a broadcast network environment, the media content is sourced from In a broadcast network environment, the media content is sourced from
various content providers across different locations. The 4k various content providers across different locations. The 4k
broadcast video is an evolving service placing enormous demand on broadcast video is an evolving service placing enormous demand on
network infrastructure in terms of low latency, faster convergence, network infrastructure in terms of low latency, faster convergence,
high throughput, and high bandwidth. high throughput, and high bandwidth.
In a typical broadcast satellite network environment, the receivers In a typical broadcast satellite network environment, the receivers
are the satellite terminal nodes which will receive the content from are the satellite terminal nodes which will receive the content from
various sources and feed the data to the satellite. Typically a various sources and feed the data to the satellite. Typically a
multicast group address is assigned for each source. Currently the multicast group address is assigned for each source. Currently the
receivers can join the sources using either PIM-SM [RFC4601] or PIM- receivers can join the sources using either PIM-SM [RFC7761] or PIM-
SSM [RFC4607]. SSM [RFC4607].
In such network scenarios, normally PIM will be the multicast routing In such network scenarios, normally PIM will be the multicast routing
protocol used to establish the tree between ingress connecting the protocol used to establish the tree between ingress connecting the
content media sources to egress routers connecting the receivers. In content media sources to egress routers connecting the receivers. In
PIM-SM mode, the receivers relies on shared tree to learn the source PIM-SM mode, the receivers relies on shared tree to learn the source
address and build source tree while in PIM-SSM mode, IGMPv3 is used address and build source tree while in PIM-SSM mode, IGMPv3 is used
by receiver to signal the source address to the egress router. In by receiver to signal the source address to the egress router. In
either case, as the number of sources increases, the number of either case, as the number of sources increases, the number of
multicast trees in the core also increases resulting in more multicast trees in the core also increases resulting in more
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With BIER in 4k broadcast satellite network environment, there is no With BIER in 4k broadcast satellite network environment, there is no
need to run PIM in the core and no need to maintain any multicast need to run PIM in the core and no need to maintain any multicast
state. The obvious advantage with BIER is the low multicast state state. The obvious advantage with BIER is the low multicast state
maintained in the core and the faster convergence (which is typically maintained in the core and the faster convergence (which is typically
at par with the unicast convergence). The edge router at the content at par with the unicast convergence). The edge router at the content
source facility can act as BIFR router and the edge router at the source facility can act as BIFR router and the edge router at the
receiver facility can act as BFER routers. Any addition of a new receiver facility can act as BFER routers. Any addition of a new
content source or new satellite Terminal nodes can be added content source or new satellite Terminal nodes can be added
seamlessly in to the BEIR domain. The group membership from the seamlessly in to the BEIR domain. The group membership from the
receivers to the sources can be provisioned either by BGP or an SDN receivers to the sources can be provisioned either by Border Gateway
controller. Protocol (BGP) or an SDN controller.
3.9. Distributed Storage Cluster 3.9. Distributed Storage Cluster
Distributed Storage Clusters can benefit from dynamically targeted Distributed Storage Clusters can benefit from dynamically targeted
multicast messaging both for dynamic load-balancing negotiations and multicast messaging both for dynamic load-balancing negotiations and
efficient concurrent replication of content to multiple targets. efficient concurrent replication of content to multiple targets.
For example, in the NexentaEdge storage cluster (by Nexenta Systems) For example, in the NexentaEdge storage cluster (by Nexenta Systems)
a Chunk Put transaction is accomplished with the following steps: a Chunk Put transaction is accomplished with the following steps:
o The Client multicasts a Chunk Put Request to a multicast group o The Client multicasts a 'Chunk Put Request' to a multicast group
known as a Negotiating Group. This group holds a small number of known as a Negotiating Group. This group holds a small number of
storage targets that are collectively responsible for providing storage targets that are collectively responsible for providing
storage for a stable subset of the chunks to be stored. In storage for a stable subset of the chunks to be stored. In
NexentaEdge this is based upon a cryptographic hash of the Object NexentaEdge this is based upon a cryptographic hash of the Object
Name or the Chunk payload. Name or the Chunk payload.
o Each recipient of the Chunk Put Request unicasts a Chunk Put o Each recipient of the 'Chunk Put Request' unicasts a 'Chunk Put
Response to the Client indicating when it could accept a transfer Response' to the Client indicating when it could accept a transfer
of the Chunk. of the Chunk.
o The Client selects a different multicast group (a Rendezvous o The Client selects a different multicast group (a Rendezvous
Group) which will target the set storage targets selected to hold Group) which will target the set storage targets selected to hold
the Chunk. This is a subset of the Negotiation Group, presumably the Chunk. This is a subset of the Negotiation Group, presumably
selected so as to complete the transfer as early as possible. selected so as to complete the transfer as early as possible.
o >The Client multicasts a Chunk Put Accept message to inform the o The Client multicasts a 'Chunk Put Accept' message to inform the
Negotiation Group of what storage targets have been selected, when Negotiation Group of what storage targets have been selected, when
the transfer will occur and over what multicast group. the transfer will occur and over what multicast group.
o The client performs the multicast transfer over the Rendezvous o The client performs the multicast transfer over the Rendezvous
Group at the agreed upon time. Group at the agreed upon time.
o Each recipient sends a Chunk Put Ack to positively or negatively o Each recipient sends a 'Chunk Put Ack' to positively or negatively
acknowledge the chunk transfer. acknowledge the chunk transfer.
o The client will retry the entire transaction as needed if there o The client will retry the entire transaction as needed if there
are not yet sufficient replicas of the Chunk. are not yet sufficient replicas of the Chunk.
Chunks are retrieved by multicasting a Chunk Get Request to the same Chunks are retrieved by multicasting a 'Chunk Get Request' to the
Negotiating Group, collecting Chunk Get Responses, picking one source same Negotiating Group, collecting 'Chunk Get Responses', picking one
from those responses, sending a Chunk Get Accept message to identify source from those responses, sending a 'Chunk Get Accept' message to
the selected source and having the selected storage server unicast identify the selected source and having the selected storage server
the chunk to the source. unicast the chunk to the source.
Chunks are found by the Object Name or by having the payload Chunks are found by the Object Name or by having the payload
cryptographic hash of payload chunks be recorded in a "chunk cryptographic hash of payload chunks be recorded in a "chunk
reference" in a metadata chunk. The metadata chunks are found using reference" in a metadata chunk. The metadata chunks are found using
the Object Name. the Object Name.
The general pattern in use here, which should apply to other cluster The general pattern in use here, which should apply to other cluster
applications, is that multicast messages are sent amongst a applications, is that multicast messages are sent amongst a
dynamically selected subset of the entire cluster, which may result dynamically selected subset of the entire cluster, which may result
in exchanging further messages over a smaller subset even more in exchanging further messages over a smaller subset even more
dynamically selected. dynamically selected.
Currently the distributed storage application discussed use of MLD Currently the distributed storage application discussed use of
managed IPV6 multicast groups. This in turn requires either a push- Multicast Listener Discovery (MLD) [RFC3810] managed IPV6 multicast
based mechanism for dynamically configuring Rendezvous Groups or pre- groups. This in turn requires either a push-based mechanism for
provisioning a very large number of potential Rendezvous Groups and dynamically configuring Rendezvous Groups or pre-provisioning a very
dynamically selecting the multicast group that will deliver to the large number of potential Rendezvous Groups and dynamically selecting
selected set of storage targets. the multicast group that will deliver to the selected set of storage
targets.
BIER would eliminate the need for a vast number of multicast groups. BIER would eliminate the need for a vast number of multicast groups.
The entire cluster can be represented as a single BIER domain using The entire cluster can be represented as a single BIER domain using
only the default sub-domain. Each Negotiating Group is simply a only the default sub-domain. Each Negotiating Group is simply a
subset of the whole that is deterministically selected by the subset of the whole that is deterministically selected by the
Cryptographic Hash of the Object Name or Chunk Payload. Each Cryptographic Hash of the Object Name or Chunk Payload. Each
Rendezvous Group is a further subset of the Negotiating Group. Rendezvous Group is a further subset of the Negotiating Group.
In a simple mapping of the MLD managed multicast groups, each In a simple mapping of the MLD managed multicast groups, each
Negotiating Group could be represented by a short bit string selected Negotiating Group could be represented by a short bit string selected
by a Set Identifier. The Set Identier effectively becomes the by a Set Identifier. The Set Identier effectively becomes the
Negotiating Group. To address the entire Negotiating Group the bit Negotiating Group. To address the entire Negotiating Group the bit
string is set to all ones. To later address a subset of the group a string is set to all ones. To later address a subset of the group a
subset bit string is used. subset bit string is used.
This allows a short fixed size BIER header to multicast to a very This allows a short fixed size BIER header to multicast to a very
large storage cluster. large storage cluster.
3.10. HTTP-Level Multicast 3.10. Hyper Text Transfer Protocol (HTTP) Level Multicast
Scenarios where a number of HTTP-level clients are quasi- Scenarios where a number of HTTP [RFC7231] clients are quasi-
synchronously accessing the same HTTP-level resource can benefit from synchronously accessing the same HTTP-level resource can benefit from
the dynamic multicast group formation enabled by BIER. the dynamic multicast group formation enabled by BIER.
For example, in the FLIPS (Flexible IP Services) solution by For example, in the FLIPS (Flexible IP Services) solution by
InterDigital, network attachment points (NAPs) provide a protocol InterDigital, network attachment points (NAPs) provide a protocol
mapping from HTTP to an efficient BIER-compliant transfer along a mapping from HTTP to an efficient BIER-compliant transfer along a
bit-indexed path between an ingress (here the NAP to which the bit-indexed path between an ingress (here the NAP to which the
clients connect) and an egress (here the NAP to which the HTTP-level clients connect) and an egress (here the NAP to which the HTTP-level
server connects). This is accomplished with the following steps: server connects). This is accomplished with the following steps:
o at the client NAP, the HTTP request is terminated at the HTTP o at the client NAP, the HTTP request is terminated at the HTTP
level at a local HTTP proxy. level at a local HTTP proxy.
o the HTTP request is published by the client NAP towards the FQDN o the HTTP request is published by the client NAP towards the Fully
of the server defined in the HTTP request Qualified Domain Names (FQDN) of the server defined in the HTTP
request
* if no local BIER forwarding information exists to the server * if no local BIER forwarding information exists to the server
(NAP), a path computation entity (PCE) is consulted, which (NAP), a path computation entity (PCE) is consulted, which
calculates a unicast path to the egress NAP (here the server calculates a unicast path to the egress NAP (here the server
NAP). The PCE provides the forwarding information to the NAP). The PCE provides the forwarding information to the
client NAP, which in turn caches the result. client NAP, which in turn caches the result.
+ if the local BIER forwarding information exists in the NAP- + if the local BIER forwarding information exists in the NAP-
local cache, it is used instead. local cache, it is used instead.
o Upon arrival of a client NAP request at the server NAP, the server o Upon arrival of a client NAP request at the server NAP, the server
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multi-tenant data centre scenarios such as outlined in Section 3.6., multi-tenant data centre scenarios such as outlined in Section 3.6.,
the aforementioned solution can satisfy HTTP-level requests to the aforementioned solution can satisfy HTTP-level requests to
popular services and content in a multicast delivery manner. popular services and content in a multicast delivery manner.
BIER enables such solution through the bitfield representation of BIER enables such solution through the bitfield representation of
forwarding information, which is in turn used for ad-hoc multicast forwarding information, which is in turn used for ad-hoc multicast
group formation at the HTTP request level. While such solution works group formation at the HTTP request level. While such solution works
well in SDN-enabled intra- domain scenarios, BIER would enable the well in SDN-enabled intra- domain scenarios, BIER would enable the
realization of such scenarios in multi-domain scenarios over legacy realization of such scenarios in multi-domain scenarios over legacy
transport networks without relying on SDN-controlled infrastructure. transport networks without relying on SDN-controlled infrastructure.
Also see [I-D.ietf-bier-multicast-http-response] for more
information.
4. Security Considerations 4. Security Considerations
There are no security issues introduced by this draft. There are no security issues introduced by this draft.
5. IANA Considerations 5. IANA Considerations
There are no IANA consideration introduced by this draft. There are no IANA consideration introduced by this draft.
6. Acknowledgments 6. Acknowledgments
skipping to change at page 13, line 47 skipping to change at page 14, line 15
7. Contributing Authors 7. Contributing Authors
Dirk Trossen Dirk Trossen
InterDigital Inc InterDigital Inc
Email: dirk.trossen@interdigital.com Email: dirk.trossen@interdigital.com
8. References 8. References
8.1. Normative References 8.1. Normative References
[I-D.ietf-bier-mvpn]
Rosen, E., Sivakumar, M., Wijnands, I., Aldrin, S.,
Dolganow, A., and T. Przygienda, "Multicast VPN Using
BIER", draft-ietf-bier-mvpn-01 (work in progress), July
2015.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Przygienda, T., and S. Aldrin, "Multicast Using Bit Index Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
Explicit Replication (BIER)", RFC 8279, Explicit Replication (BIER)", RFC 8279,
DOI 10.17487/RFC8279, November 2017, DOI 10.17487/RFC8279, November 2017,
<https://www.rfc-editor.org/info/rfc8279>. <https://www.rfc-editor.org/info/rfc8279>.
[RFC8556] Rosen, E., Ed., Sivakumar, M., Przygienda, T., Aldrin, S.,
and A. Dolganow, "Multicast VPN Using Bit Index Explicit
Replication (BIER)", RFC 8556, DOI 10.17487/RFC8556, April
2019, <https://www.rfc-editor.org/info/rfc8556>.
8.2. Informative References 8.2. Informative References
[RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas, [I-D.ietf-bier-multicast-http-response]
"Protocol Independent Multicast - Sparse Mode (PIM-SM): Trossen, D., Rahman, A., Wang, C., and T. Eckert,
Protocol Specification (Revised)", RFC 4601, "Applicability of BIER Multicast Overlay for Adaptive
DOI 10.17487/RFC4601, August 2006, Streaming Services", draft-ietf-bier-multicast-http-
<https://www.rfc-editor.org/info/rfc4601>. response-03 (work in progress), February 2020.
[RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener
Discovery Version 2 (MLDv2) for IPv6", RFC 3810,
DOI 10.17487/RFC3810, June 2004,
<https://www.rfc-editor.org/info/rfc3810>.
[RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for [RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for
IP", RFC 4607, DOI 10.17487/RFC4607, August 2006, IP", RFC 4607, DOI 10.17487/RFC4607, August 2006,
<https://www.rfc-editor.org/info/rfc4607>. <https://www.rfc-editor.org/info/rfc4607>.
[RFC4664] Andersson, L., Ed. and E. Rosen, Ed., "Framework for Layer [RFC4664] Andersson, L., Ed. and E. Rosen, Ed., "Framework for Layer
2 Virtual Private Networks (L2VPNs)", RFC 4664, 2 Virtual Private Networks (L2VPNs)", RFC 4664,
DOI 10.17487/RFC4664, September 2006, DOI 10.17487/RFC4664, September 2006,
<https://www.rfc-editor.org/info/rfc4664>. <https://www.rfc-editor.org/info/rfc4664>.
skipping to change at page 14, line 47 skipping to change at page 15, line 24
[RFC5331] Aggarwal, R., Rekhter, Y., and E. Rosen, "MPLS Upstream [RFC5331] Aggarwal, R., Rekhter, Y., and E. Rosen, "MPLS Upstream
Label Assignment and Context-Specific Label Space", Label Assignment and Context-Specific Label Space",
RFC 5331, DOI 10.17487/RFC5331, August 2008, RFC 5331, DOI 10.17487/RFC5331, August 2008,
<https://www.rfc-editor.org/info/rfc5331>. <https://www.rfc-editor.org/info/rfc5331>.
[RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/ [RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/
BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, February BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, February
2012, <https://www.rfc-editor.org/info/rfc6513>. 2012, <https://www.rfc-editor.org/info/rfc6513>.
[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014,
<https://www.rfc-editor.org/info/rfc7231>.
[RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger, [RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
L., Sridhar, T., Bursell, M., and C. Wright, "Virtual L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
eXtensible Local Area Network (VXLAN): A Framework for eXtensible Local Area Network (VXLAN): A Framework for
Overlaying Virtualized Layer 2 Networks over Layer 3 Overlaying Virtualized Layer 2 Networks over Layer 3
Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014, Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014,
<https://www.rfc-editor.org/info/rfc7348>. <https://www.rfc-editor.org/info/rfc7348>.
[RFC7432] Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A., [RFC7432] Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A.,
Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based
Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432, February Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432, February
2015, <https://www.rfc-editor.org/info/rfc7432>. 2015, <https://www.rfc-editor.org/info/rfc7432>.
[RFC7761] Fenner, B., Handley, M., Holbrook, H., Kouvelas, I.,
Parekh, R., Zhang, Z., and L. Zheng, "Protocol Independent
Multicast - Sparse Mode (PIM-SM): Protocol Specification
(Revised)", STD 83, RFC 7761, DOI 10.17487/RFC7761, March
2016, <https://www.rfc-editor.org/info/rfc7761>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>. July 2018, <https://www.rfc-editor.org/info/rfc8402>.
Authors' Addresses Authors' Addresses
Nagendra Kumar Nagendra Kumar
Cisco Cisco
7200 Kit Creek Road 7200 Kit Creek Road
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