Terminology for NG MVPN

BFD

Bidirectional Forwarding Detection. A common fault detecting mechanism that uses Hello packets to quickly detect a link status change and notify a protocol of the change. The protocol then determines whether to establish or tear down a peer relationship.

DR

Designated router. A router that applies only to PIM-SM. On the network segment that connects to a multicast source, a DR sends Register messages to the RP. On the network segment that connects to multicast receivers, a DR sends Join messages to the RP. In SSM mode, a DR at the group member side directly sends Join messages to a multicast source.

IGMP

Internet Group Management Protocol. A signaling mechanism that implements communication between hosts and routers on IP multicast leaf networks.

By periodically sending IGMP messages, a host joins or leaves a multicast group, and a router identifies whether a multicast group contains members.

Join

A type of message used on PIM-SM networks. When a host requests to join a network segment, the DR of the network segment sends a Join message to the RP hop by hop to generate a multicast route. When the RP starts an SPT switchover, the RP sends a Join message to the source hop by hop to generate a multicast route.

PIM

Protocol Independent Multicast. A multicast routing protocol.

Reachable unicast routes are the basis of PIM forwarding. PIM uses the existing unicast routing information to perform RPF check on multicast packets to create multicast routing entries and set up an MDT.

Prune

A type of message. If there are no multicast group members on a downstream interface, a router sends a prune message to the upstream node. After receiving the prune message, the upstream node removes the downstream interface from the downstream interface list and stops forwarding data of the specified group to the downstream interface.

P-tunnel

A public network tunnel used to transmit VPN multicast traffic. A P-tunnel can be established using GRE, MPLS, or other tunneling technologies.

PMSI

A logical tunnel used by a public network to transmit VPN multicast traffic. A sender PE transmits VPN multicast traffic to receiver PEs over a PMSI tunnel. Receiver PEs determine whether to accept the VPN multicast traffic based on PMSI tunnel information. PMSI tunnels are categorized as I-PMSI or S-PMSI tunnels.

RD

Route distinguisher. An 8-byte field in a VPN IPv4 address. An RD together with a 4-byte IPv4 address prefix constructs a VPN IPv4 address to differentiate the IPv4 prefixes using the same address space.

receiver site

A site where multicast receivers reside.

receiver PE

A PE connected to a receiver site.

sender site

A site where a multicast source resides.

sender PE

A PE connected to a sender site.

(S, G)

A multicast routing entry. S indicates a multicast source, and G indicates a multicast group. After a multicast packet with S as the source address and G as the group address reaches a router, it is forwarded through the downstream interfaces of the (S, G) entry. The packet is expressed as an (S, G) packet.

(*, G)

A PIM routing entry. * indicates any source, and G indicates a multicast group. The (*, G) entry applies to all multicast packets whose group address is G. All multicast packets that are sent to G are forwarded through the downstream interfaces of the (*, G) entry, regardless of which source sends the packets.

tunnel ID

A group of information, including token, slot number of an outgoing interface, tunnel type.

VPN

Virtual private network. A technology that implements a private network over a public network.

VPN instance

An entity that is set up and maintained by the PE devices for directly-connected sites. Each site has its VPN instance on a PE device. A VPN instance is also called a VPN routing and forwarding (VRF) table. A PE device has multiple forwarding tables, including a public-network routing table and one or more VRF tables.

VPN target

A BGP extended community attribute that is also called Route Target. In BGP/MPLS IP VPN, VPN target controls VPN routing information. VPN target defines a VPN-IPv4 route can be received by which site and a PE device can receive routes from which site.

MVPN target

Control MVPN A-D route advertisement. MVPN target functions in a similar way as VPN target on unicast VPNs.

A-D

autodiscovery

AS

autonomous system

BGP

Border Gateway Protocol

CE

customer edge

C-G

customer multicast group address

C-S

customer multicast source address

FRR

fast reroute

LDP

Label Distribution Protocol

mLDP

Multipoint LDP

MPLS

Multiprotocol Label Switching

MVPN

multicast VPN

NG MVPN

next-generation multicast VPN

NLRI

network layer reachability information

P2MP

point-to-multipoint

P

provider (device)

PE

provider edge

PIM

Protocol Independent Multicast

PIM-SM

Protocol Independent Multicast-Sparse Mode

RP

rendezvous point

RPF

reverse path forwarding

RSVP

Resource Reservation Protocol

SSM

source-specific multicast

TE

traffic engineering

VPN

virtual private network