Prerequisites for MVPN mLDP Partitioned MDT

MVPN BGP auto discovery should be configured.

Restrictions for MVPN mLDP Partitioned MDT

  • PIM Dense mode (except for Auto-RP) and PIM-Bidir in the VRF are not supported.

  • BGP multicast signaling is supported and PIM signaling is not supported.

  • Only point-to-multi point (P2MP) mLDP label switch path is supported.

  • Same VRF (for which mLDP in-band signaling is configured) needs to be configured on IPv4

  • mLDP Partitioned multicast distribution tree (MDT) supports PIM-Source Specific Multicast (SSM) traffic only.

  • Rosen mLDP recursive FEC is not supported. Partitioned MDT is applicable to inter-AS VPN (Inter AS option B and option C are not supported).

  • mLDP filtering is not supported.

  • Only interface-based strict RPF is supported with partitioned MDT.

  • The strict-rpf interface command is not supported.

  • For mLDP Partitioned multicast distribution tree (MDT) to work with PIM-Sparse Mode (SM) traffic, configure only a single ingress PE and ensure that the strict-rpf interface command is disabled. Configuring multiple PE ingress is not allowed.

Information About MVPN mLDP Partitioned MDT

The MVPN mLDP partitioned MDT feature uses Upstream Multicast Hop-Provider Multicast Service Interface (UMS-PMSI), a subset of provider edge routers (PEs) to transmit data to other PEs; similar to the usage of multiple selective-PMSI (S-PMSI) by data multicast distribution tree (MDT). In the partitioned MDT approach, egress PE routers that have interested receivers for traffic from a particular ingress PE joins a point-to-point (P2P) connection rooted at that ingress PE. This makes the number of ingress PE routers in a network to be low resulting in a limited number of trees in the core.

Overview of MVPN mLDP Partitioned MDT

MVPN allows a service provider to configure and support multicast traffic in an MPLS VPN environment. This type supports routing and forwarding of multicast packets for each individual VPN routing and forwarding (VRF) instance, and it also provides a mechanism to transport VPN multicast packets across the service provider backbone. In the MLDP case, the regular label switch path forwarding is used, so core does not need to run PIM protocol. In this scenario, the c-packets are encapsulated in the MPLS labels and forwarding is based on the MPLS Label Switched Paths (LSPs).

The MVPN mLDP service allows you to build a Protocol Independent Multicast (PIM) domain that has sources and receivers located in different sites.

To provide Layer 3 multicast services to customers with multiple distributed sites, service providers look for a secure and scalable mechanism to transmit customer multicast traffic across the provider network. Multicast VPN (MVPN) provides such services over a shared service provider backbone, using native multicast technology similar to BGP/MPLS VPN.

MVPN emulates MPLS VPN technology in its adoption of the multicast domain (MD) concept, in which provider edge (PE) routers establish virtual PIM neighbor connections with other PE routers that are connected to the same customer VPN. These PE routers thereby form a secure, virtual multicast domain over the provider network. Multicast traffic is then transmitted across the core network from one site to another, as if the traffic were going through a dedicated provider network.

Separate multicast routing and forwarding tables are maintained for each VPN routing and forwarding (VRF) instance, with traffic being sent through VPN tunnels across the service provider backbone.

In the Rosen MVPN mLDP solution, a multipoint-to-multipoint (MP2MP) default MDT is setup to carry control plane and data traffic. A disadvantage with this solution is that all PE routers that are part of the MVPN need to join this default MDT tree. Setting up a MP2MP tree between all PE routers of a MVPN is equivalent to creating N P2MP trees rooted at each PE (Where N is the number of PE routers). In an Inter-AS (Option A) solution this problem is exacerbated since all PE routers across all AS’es need to join the default MDT. Another disadvantage of this solution is that any packet sent through a default MDT reaches all the PE routers even if there is no requirement.

In the partitioned MDT approach, only those egress PE routers that receive traffic requests from a particular ingress PE join the PMSI configured at that ingress PE. This makes the number of ingress PE routers in a network to be low resulting in a limited number of trees in the core.

How to Configure MVPN mLDP Partitioned MDT

Configuring MVPN mLDP Partitioned MDT

Procedure

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 3

ip multicast-routing vrf vrf-name

Example:


Device(config)# ip multicast-routing vrf VRF

Enables IP multicast routing for the MVPN VRF specified for the vrf-name argument.

Step 4

ip vrf vrf-name

Example:


Device(config-vrf)# ip vrf VRF

Defines a VRF instance and enters VRF configuration mode.

Step 5

rd route-distinguisher

Example:


Device(config-vrf)# rd 50:11

Creates a route distinguisher (RD) (in order to make the VRF functional).

  • Creates the routing and forwarding tables, associates the RD with the VRF instance, and specifies the default RD for a VPN.

Step 6

route target export route-target-ext-community

Example:


Device(config-vrf)# route target export 100:100

Creates an export route target extended community for the specified VRF.

Step 7

route target import route-target-ext-community

Example:


Device(config-vrf)# route target import 100:100

Creates an import route target extended community for the specified VRF.

Step 8

mdt partitioned mldp p2mp

Example:


Device(config-vrf)# mdt partitioned mldp p2mp

Configures partitioned MDT.

Step 9

mdt auto-discovery mldp [inter-as]

Example:


Device(config-vrf)# mdt auto-discovery mldp inter-as

Enables inter-AS operation with BGP A-D.

Step 10

exit

Example:


Device(config-vrf)# exit

Exits the VRF configuration mode and returns to privileged EXEC mode.

Step 11

show ip pim mdt

Example:


Device# show ip pim mdt

Displays information on wildcard S-PMSI A-D route.

Step 12

show ip pim vrf mdt [send | receive]

Example:


Device# show ip pim vrf mdt send

Displays information on wildcard S-PMSI A-D route along with MDT group mappings received from other PE routers or the MDT groups that are currently in use.

Step 13

show ip multicast mpls vif

Example:


Device# end

Displays the LSPVIFs created for all the PEs.

Configuration Examples for MVPN mLDP Partitioned MDT

Example: MVPN mLDP Partitioned MDT



ip multicast-routing vrf VRF
   ip vrf VRF
   rd 50:11
   route target export 100:100
   route target import 100:100
   mdt strict-rpf interface
   mdt partitioned mldp p2mp
   mdt auto-discovery mldp inter-as  
  !
 !

Feature History for Configuring MVPN mLDP Partitioned MDT

Table 1. Feature History for Configuring MVPN mLDP Partitioned MDT

Release

Feature

Feature Information

Cisco IOS XE Everest 16.5.1a

MVPN mLDP Partitioned MDT

In the partitioned MDT approach, only those egress PE routers that receive traffic requests from a particular ingress PE join a S-PMSI configured at that ingress PE. Typically the number of ingress PE routers in a network is low resulting in a limited number of trees in the core.

Cisco IOS XE 17.13.1

mLDP based MVPN profile 14

This feature supports partitioned MDT in an Inter AS MPLS VPN network deployed with option B.