- play_arrow Overview
- play_arrow Managing Group Membership
- play_arrow Configuring IGMP and MLD
- play_arrow Configuring IGMP Snooping
- IGMP Snooping Overview
- Overview of Multicast Forwarding with IGMP Snooping or MLD Snooping in an EVPN-VXLAN Environment
- Configuring IGMP Snooping on Switches
- Example: Configuring IGMP Snooping on Switches
- Example: Configuring IGMP Snooping on EX Series Switches
- Verifying IGMP Snooping on EX Series Switches
- Changing the IGMP Snooping Group Timeout Value on Switches
- Monitoring IGMP Snooping
- Example: Configuring IGMP Snooping
- Example: Configuring IGMP Snooping on SRX Series Devices
- Configuring Point-to-Multipoint LSP with IGMP Snooping
- play_arrow Configuring MLD Snooping
- Understanding MLD Snooping
- Configuring MLD Snooping on an EX Series Switch VLAN (CLI Procedure)
- Configuring MLD Snooping on a Switch VLAN with ELS Support (CLI Procedure)
- Example: Configuring MLD Snooping on EX Series Switches
- Example: Configuring MLD Snooping on SRX Series Devices
- Configuring MLD Snooping Tracing Operations on EX Series Switches (CLI Procedure)
- Configuring MLD Snooping Tracing Operations on EX Series Switch VLANs (CLI Procedure)
- Example: Configuring MLD Snooping on EX Series Switches
- Example: Configuring MLD Snooping on Switches with ELS Support
- Verifying MLD Snooping on EX Series Switches (CLI Procedure)
- Verifying MLD Snooping on Switches
- play_arrow Configuring Multicast VLAN Registration
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- play_arrow Configuring Protocol Independent Multicast
- play_arrow Understanding PIM
- play_arrow Configuring PIM Basics
- Configuring Different PIM Modes
- Configuring Multiple Instances of PIM
- Changing the PIM Version
- Optimizing the Number of Multicast Flows on QFabric Systems
- Modifying the PIM Hello Interval
- Preserving Multicast Performance by Disabling Response to the ping Utility
- Configuring PIM Trace Options
- Configuring BFD for PIM
- Configuring BFD Authentication for PIM
- play_arrow Routing Content to Densely Clustered Receivers with PIM Dense Mode
- play_arrow Routing Content to Larger, Sparser Groups with PIM Sparse Mode
- Understanding PIM Sparse Mode
- Examples: Configuring PIM Sparse Mode
- Configuring Static RP
- Example: Configuring Anycast RP
- Configuring PIM Bootstrap Router
- Understanding PIM Auto-RP
- Configuring All PIM Anycast Non-RP Routers
- Configuring a PIM Anycast RP Router with MSDP
- Configuring Embedded RP
- Configuring PIM Filtering
- Examples: Configuring PIM RPT and SPT Cutover
- Disabling PIM
- play_arrow Configuring Designated Routers
- play_arrow Receiving Content Directly from the Source with SSM
- Understanding PIM Source-Specific Mode
- Example: Configuring Source-Specific Multicast
- Example: Configuring PIM SSM on a Network
- Example: Configuring an SSM-Only Domain
- Example: Configuring SSM Mapping
- Example: Configuring Source-Specific Multicast Groups with Any-Source Override
- Example: Configuring SSM Maps for Different Groups to Different Sources
- play_arrow Minimizing Routing State Information with Bidirectional PIM
- play_arrow Rapidly Detecting Communication Failures with PIM and the BFD Protocol
- play_arrow Configuring PIM Options
- play_arrow Verifying PIM Configurations
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- play_arrow Configuring Multicast Routing Protocols
- play_arrow Connecting Routing Domains Using MSDP
- play_arrow Handling Session Announcements with SAP and SDP
- play_arrow Facilitating Multicast Delivery Across Unicast-Only Networks with AMT
- play_arrow Routing Content to Densely Clustered Receivers with DVMRP
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- play_arrow Configuring Multicast VPNs
- play_arrow Configuring Draft-Rosen Multicast VPNs
- Draft-Rosen Multicast VPNs Overview
- Example: Configuring Any-Source Draft-Rosen 6 Multicast VPNs
- Example: Configuring a Specific Tunnel for IPv4 Multicast VPN Traffic (Using Draft-Rosen MVPNs)
- Example: Configuring Source-Specific Draft-Rosen 7 Multicast VPNs
- Understanding Data MDTs
- Example: Configuring Data MDTs and Provider Tunnels Operating in Any-Source Multicast Mode
- Example: Configuring Data MDTs and Provider Tunnels Operating in Source-Specific Multicast Mode
- Examples: Configuring Data MDTs
- play_arrow Configuring Next-Generation Multicast VPNs
- Understanding Next-Generation MVPN Network Topology
- Understanding Next-Generation MVPN Concepts and Terminology
- Understanding Next-Generation MVPN Control Plane
- Next-Generation MVPN Data Plane Overview
- Enabling Next-Generation MVPN Services
- Generating Next-Generation MVPN VRF Import and Export Policies Overview
- Multiprotocol BGP MVPNs Overview
- Configuring Multiprotocol BGP Multicast VPNs
- BGP-MVPN Inter-AS Option B Overview
- ACX Support for BGP MVPN
- Example: Configuring MBGP MVPN Extranets
- Understanding Redundant Virtual Tunnel Interfaces in MBGP MVPNs
- Example: Configuring Redundant Virtual Tunnel Interfaces in MBGP MVPNs
- Understanding Sender-Based RPF in a BGP MVPN with RSVP-TE Point-to-Multipoint Provider Tunnels
- Example: Configuring Sender-Based RPF in a BGP MVPN with RSVP-TE Point-to-Multipoint Provider Tunnels
- Example: Configuring Sender-Based RPF in a BGP MVPN with MLDP Point-to-Multipoint Provider Tunnels
- Configuring MBGP MVPN Wildcards
- Distributing C-Multicast Routes Overview
- Exchanging C-Multicast Routes
- Generating Source AS and Route Target Import Communities Overview
- Originating Type 1 Intra-AS Autodiscovery Routes Overview
- Signaling Provider Tunnels and Data Plane Setup
- Anti-spoofing support for MPLS labels in BGP/MPLS IP VPNs (Inter-AS Option B)
- BGP-MVPN SD-WAN Overlay
- play_arrow Configuring PIM Join Load Balancing
- Use Case for PIM Join Load Balancing
- Configuring PIM Join Load Balancing
- PIM Join Load Balancing on Multipath MVPN Routes Overview
- Example: Configuring PIM Join Load Balancing on Draft-Rosen Multicast VPN
- Example: Configuring PIM Join Load Balancing on Next-Generation Multicast VPN
- Example: Configuring PIM Make-Before-Break Join Load Balancing
- Example: Configuring PIM State Limits
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- play_arrow Troubleshooting
- play_arrow Knowledge Base
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- play_arrow Configuration Statements and Operational Commands
Overview
Bit Index Explicit Replication (BIER) architecture supports the optimal forwarding of multicast packets without requiring a legacy multicast protocol to build multicast trees or for intermediate routers to maintain any per-multicast-flow state which simplifies control and forwarding planes.
Multicast forwarding is achieved by encapsulating the multicast packet with a BIER header at the ingress router. The BIER header contains a bit string, with each bit representing an egress router in the multicast domain. This bit is mapped from a unique ID assigned to each BIER enabled egress or ingress router. A multicast flow overlay protocol like BGP-MVPN helps the BFERs (Bit Forwarding Egress Router) communicate with the BFIRs (Bit Forwarding Ingress Router) and tell them that they need to receive certain overlay multicast traffic, so that the BFIRs can set up an overlay multicast forwarding state with appropriate BIER encapsulation information.
Benefits of BIER
BIER implementation results in considerable simplification of the multicast network, due to the elimination of:
the per-flow state.
explicit tree-building protocols.
BIER Terminology
The following terms are widely used in this topic:
Term | Definition |
|---|---|
BIER | Bit Index Explicit Replication. |
BFR | A Bit Forwarding Router is a BIER enabled router with a unique BFR prefix and optionally, a BFR-ID . A BFR establishes router adjacencies, computes the BIER routing and forwarding tables, and forwards or replicates BIER packets. There are three types of BFRs - BFIR, BFER and transit BFR. |
BFIR | A Bit Forwarding Ingress Router is the first router in the BIER domain entered by a multicast packet. The BFIR adds a BIER header and forwards the packet using the BIER forwarding table. |
BFER | A Bit Forwarding Egress Router is the last router that processes a BIER packet in a BIER domain. The BFER removes the BIER header before forwarding the packet. |
Transit BFR | A transit Bit Forwarding Router is a router in the BIER domain that receives a multicast data packet from a BFR in the same BIER domain, and forwards the packet to another BFR within the same BIER domain. |
BFR prefix | A BFR prefix is typically the configured loopback address of a BFR and must be a routable IP address in the BIER domain. |
BFR-ID | A BFR-ID is a number in the range of 1-65535. When a BFR-ID is encoded in a packet, it is converted to a Set-ID (SI) and a bit in the bit string (BSL). Any BFR that is an ingress or egress router in a BIER domain is assigned a BFR-ID. A BFR-ID must be unique within that BIER sub-domain. Each of these BFR-IDs is encoded as a bit in the bit string that is carried in the BIER header with each multicast packet. |
bit string | A bit string is a part of the BIER header, with each bit representing a BFER in the multicast domain. |
BSL | The length of the bit string. By default, Junos only supports 256. |
SD | Sub-domain. A BIER domain is a connected set of BFRs, each with a unique BFR-ID. A BIER domain can be divided into multiple sub-domains for various reasons. For example, it could represent a specific topology within a BIER domain. |
Set-ID | In cases where the number of BFIRs/BFERs in the network is greater than the bitstringlength (BSL), they must be divided into multiple sets. Each set is identified by a Set-ID. However, this will require a packet to be replicated to each set. Junos currently supports 1 to 4 sets. |
F-BM | Forwarding Bit Mask is the property of a BFR-neighbor which represents all the BFERs that are reachable through that BFR neighbour. |
BIFT | The BIER Forwarding Table is used by the BFR to identify which neighbors the packet should be sent to. The BIFT is created by calculating how each BFER is reached in the IGP routing underlay. Each BIFT entry maps a BFER's BFR-ID % BSL to a BFR neighbor and its corresponding F-BM. Each BIFT is specific to a particular sub-domain and Set-Identifier (SI). A BIFT's name is in the form of
|
BIRT | The BIER Routing Table. The routing protocol underlay (IS-IS for example) router advertises the BFR-prefix and sub-domain information inside IS-IS sub-TLVs which are flooded throughout the IS-IS domain. On the receiver side, IS-IS routers parse this BIER sub-domain information associated with the BFR-Prefix and derive the route and next-hop information. These routes are then installed into a routing table called BIRT. Routes in BIRT are keyed in on BIER prefixes. A BIRT's name is in the form of
|
BIER Architecture
BIER architecture has three layers:
Routing underlay – The underlay establishes adjacencies between pairs of BFRs, and determines one or more optimal paths from a BFR to a set of target BFRs.
BIER layer - The BIER layer consists of the protocol and procedures that are used in order to transmit a multicast data packet across a BIER domain, from the BFIR to the BFERs.
Multicast flow overlay - The overlay consists of a set of protocols and procedures that enable the following set of functions.
When a BFIR receives a multicast data packet from outside the BIER domain, the BFIR must determine the set of BFERs for that packet. This information is provided by the multicast flow overlay.
When a BFER receives a BIER-encapsulated packet from inside the BIER domain, the BFER must determine how to forward the packet. This information is provided by the multicast flow overlay. BGP-MVPN is an example of a multicast flow overlay.
