• Hardware Offloaded BFD for PIMv4 is supported.

• IPv4 and IPV6 static groups for both IGMPv2/v3 and MLDv1/v2 are supported.

• Protocol Independent Multicast in Source-Specific Multicast (PIM-SSM) mapping is supported.

• PIMv4 SSM and PIMv6 SSM over Bundle sub-interface are supported.

• Load balancing for multicast traffic for ECMP links and bundles is supported. However, an RPF check is performed on the multicast routers to ensure loop prevention in multicast trees.

• IPv6 multicast MLD joins are subjected to hop by hop LPTS punt policer. Tweaking this policer to a higher value achieves convergence at higher scale.

  Also, adjust the ICMP control traffic LPTS hardware policer to a higher value for optimal convergence at higher scale.

• Redundant sources for IPv6 PIM SSM is supported.

Note	You must enable multicast-routing in the default VRF to use multicast in some other VRF.

Protocol Independent Multicast (PIM) is a multicast routing protocol used to create multicast distribution trees, which are used to forward multicast data packets.

Proper operation of multicast depends on knowing the unicast paths towards a source or an RP. PIM relies on unicast routing protocols to derive this reverse-path forwarding (RPF) information. As the name PIM implies, it functions independently of the unicast protocols being used. PIM relies on the Routing Information Base (RIB) for RPF information. Protocol Independent Multicast (PIM) is designed to send and receive multicast routing updates.

PIM on Bundle-Ethernet subinterface is supported.

The BFD Support for Multicast (PIM) feature, also known as PIM BFD, registers PIM as a client of BFD. PIM can then utilize BFD's fast adjacency failure detection. When PIM BFD is enabled, BFD enables faster failure detection without waiting for hello messages from PIM.

At PIMs request, as a BFD client, BFD establishes and maintains a session with an adjacent node for maintaining liveness and detecting forwarding path failure to the adjacent node. PIM hellos will continue to be exchanged between the neighbors even after BFD establishes and maintains a BFD session with the neighbor. The behavior of the PIM hello mechanism is not altered due to the introduction of this feature. Although PIM depends on the Interior Gateway Protocol (IGP) and BFD is supported in IGP, PIM BFD is independent of IGP's BFD.

Protocol Independent Multicast (PIM) uses a hello mechanism for discovering new PIM neighbors between adjacent nodes. The minimum failure detection time in PIM is 3 times the PIM Query-Interval. To enable faster failure detection, the rate at which a PIM hello message is transmitted on an interface is configurable. However, lower intervals increase the load on the protocol and can increase CPU and memory utilization and cause a system-wide negative impact on performance. Lower intervals can also cause PIM neighbors to expire frequently as the neighbor expiry can occur before the hello messages received from those neighbors are processed. When PIM BFD is enabled, BFD enables faster failure detection without waiting for hello messages from PIM.

The PIM bootstrap router (BSR) provides a fault-tolerant, automated RP discovery and distribution mechanism that simplifies the Auto-RP process. This feature is enabled by default allowing routers to dynamically learn the group-to-RP mappings.

PIM uses the BSR to discover and announce RP-set information for each group prefix to all the routers in a PIM domain. This is the same function accomplished by Auto-RP, but the BSR is part of the PIM specification. The BSR mechanism interoperates with Auto-RP on Cisco routers.

To avoid a single point of failure, you can configure several candidate BSRs in a PIM domain. A BSR is elected among the candidate BSRs automatically.

Candidates use bootstrap messages to discover which BSR has the highest priority. The candidate with the highest priority sends an announcement to all PIM routers in the PIM domain that it is the BSR.

Routers that are configured as candidate RPs unicast to the BSR the group range for which they are responsible. The BSR includes this information in its bootstrap messages and disseminates it to all PIM routers in the domain. Based on this information, all routers are able to map multicast groups to specific RPs. As long as a router is receiving the bootstrap message, it has a current RP map.

Sparse-mode PIM uses the RPF lookup function to determine where it needs to send joins and prunes. (S,G) joins (which are source-tree states) are sent toward the source. (*,G) joins (which are shared-tree states) are sent toward the RP.

RPF vector is a PIM proxy that lets core routers without RPF information forward join and prune messages for external sources (for example, a MPLS-based BGP-free core, where the MPLS core router is without external routes learned from BGP). The RPF vector encoding is now compatible with the new IETF encoding. The new IETF standard encodes PIM messages using PIM Hello option 26.

When PIM is used in SSM mode, multicast routing is easier to manage. This is because RPs (rendezvous points) are not required and therefore, no shared trees (*,G) are built.

There is no specific IETF document defining PIM-SSM. However, RFC4607 defines the overall SSM behavior.

In the rest of this document, we use the term PIM-SSM to describe PIM behavior and configuration when SSM is used.

PIM in Source-Specific Multicast operation uses information found on source addresses for a multicast group provided by receivers and performs source filtering on traffic.

• By default, PIM-SSM operates in the 232.0.0.0/8 multicast group range for IPv4 and FF3x::/32 for IPv6. To configure these values, use the ssm range command.

• If SSM is deployed in a network already configured for PIM-SM, only the last-hop routers must be upgraded with Cisco IOS XR Software that supports the SSM feature.

• No MSDP SA messages within the SSM range are accepted, generated, or forwarded.

• SSM can be disabled using the ssm disable command.

• The ssm allow-override command allows SSM ranges to be overridden by more specific ranges.

In many multicast deployments where the source is known, protocol-independent multicast-source-specific multicast (PIM-SSM) mapping is the obvious multicast routing protocol choice to use because of its simplicity. Typical multicast deployments that benefit from PIM-SSM consist of entertainment-type solutions like the ETTH space, or financial deployments that completely rely on static forwarding.

In SSM, delivery of data grams is based on (S,G) channels. Traffic for one (S,G) channel consists of datagrams with an IP unicast source address S and the multicast group address G as the IP destination address. Systems receive traffic by becoming members of the (S,G) channel. Signaling is not required, but receivers must subscribe or unsubscribe to (S,G) channels to receive or not receive traffic from specific sources. Channel subscription signaling uses IGMP to include mode membership reports, which are supported only in Version 3 of IGMP (IGMPv3).

To run SSM with IGMPv3, SSM must be supported on the multicast router, the host where the application is running, and the application itself. Cisco IOS XR Software allows SSM configuration for an arbitrary subset of the IP multicast address range 224.0.0.0 through 239.255.255.255.

When an SSM range is defined, existing IP multicast receiver applications do not receive any traffic when they try to use addresses in the SSM range, unless the application is modified to use explicit (S,G) channel subscription.

To configure PIM-specific parameters, the router pim configuration mode is used. The default configuration prompt is for IPv4 and will be seen as config-pim-default-ipv4. To ensure the election of a router as PIM DR on a LAN segment, use the dr-priority command. The router with the highest DR priority will win the election. By default, at a preconfigured threshold, the last hop router can join the shortest path tree to receive multicast traffic. To change this behavior, use the command spt-threshold infinity under the router pim configuration mode. This will result in the last hop router permanently joining the shared tree. The frequency at which a router sends PIM hello messages to its neighbors can be configured by the hello-interval command. By default, PIM hello messages are sent once every 30 seconds. If the hello-interval is configured under router pim configuration mode, all the interfaces with PIM enabled will inherit this value. To change the hello interval on the interface, use the hello-interval command under interface configuration mode, as follows:

Router#configure
Router(config)#router pim
Router(config-pim-default)#address-family ipv4
Router(config-pim-default-ipv4)#dr-priority 2 
Router(config-pim-default-ipv4)#spt-threshold infinity 
Router(config-pim-default-ipv4)#interface TenGigE0/11/0/1 
Router(config-pim-ipv4-if)#dr-priority 4 
Router(config-pim-ipv4-if)#hello-interval 45 
Router(config-pim-ipv4-if)#commit

Router#show run router pim
router pim
 address-family ipv4
  dr-priority 2
  spt-threshold infinity
  interface TenGigE0/11/0/1
   dr-priority 4
   hello-interval 45

Router#show pim interface te0/11/0/1
PIM interfaces in VRF default
Address               Interface                     PIM  Nbr   Hello  DR    DR Count Intvl  Prior
100.1.1.1             TenGigE0/11/0/1                on   1     45     4     this system

Typically, PIM in sparse mode (PIM-SM) operation is used in a multicast network when relatively few routers are involved in each multicast. Routers do not forward multicast packets for a group, unless there is an explicit request for traffic. Requests are accomplished using PIM join messages, which are sent hop by hop toward the root node of the tree. The root node of a tree in PIM-SM is the rendezvous point (RP) in the case of a shared tree or the first-hop router that is directly connected to the multicast source in the case of a shortest path tree (SPT). The RP keeps track of multicast groups, and the sources that send multicast packets are registered with the RP by the first-hop router of the source.

As a PIM join travels up the tree, routers along the path set up the multicast forwarding state so that the requested multicast traffic is forwarded back down the tree. When multicast traffic is no longer needed, a router sends a PIM prune message up the tree toward the root node to prune (or remove) the unnecessary traffic. As this PIM prune travels hop by hop up the tree, each router updates its forwarding state appropriately. Ultimately, the forwarding state associated with a multicast group or source is removed. Additionally, if prunes are not explicitly sent, the PIM state will timeout and be removed in the absence of any further join messages.

This image shows IGMP and PIM-SM operating in a multicast environment.

In PIM-SM, the rendezvous point (RP) is used to bridge sources sending data to a particular group with receivers sending joins for that group. In the initial set up of state, interested receivers receive data from senders to the group across a single data distribution tree rooted at the RP. This type of distribution tree is called a shared tree or rendezvous point tree (RPT) as illustrated in Figure 4: Shared Tree and Source Tree (Shortest Path Tree), above. Data from senders is delivered to the RP for distribution to group members joined to the shared tree.

Unless the command is configured, this initial state gives way as soon as traffic is received on the leaf routers (designated router closest to the host receivers). When the leaf router receives traffic from the RP on the RPT, the router initiates a switch to a data distribution tree rooted at the source sending traffic. This type of distribution tree is called a shortest path tree or source tree. By default, the Cisco IOS XR Software switches to a source tree when it receives the first data packet from a source.

The following process describes the move from shared tree to source tree in more detail:

1. Receiver joins a group; leaf Router C sends a join message toward RP.

2. RP puts link to Router C in its outgoing interface list.

3. Source sends data; Router A encapsulates data in Register and sends it to RP.

4. RP forwards data down the shared tree to Router C and sends a join message toward Source. At this point, data may arrive twice at the RP, once encapsulated and once natively.

5. When data arrives natively (unencapsulated) at RP, RP sends a register-stop message to Router A.

6. By default, receipt of the first data packet prompts Router C to send a join message toward Source.

7. When Router C receives data on (S,G), it sends a prune message for Source up the shared tree.

8. RP deletes the link to Router C from outgoing interface of (S,G). RP triggers a prune message toward Source.

9. Join and prune messages are sent for sources and RPs. They are sent hop by hop and are processed by each PIM router along the path to the source or RP. Register and register-stop messages are not sent hop by hop. They are exchanged using direct unicast communication between the designated router that is directly connected to a source and the RP for the group.

   Note	The spt-threshold infinity command lets you configure the router so that it never switches to the shortest path tree (SPT).

Multicast Source Discovery Protocol (MSDP) is a mechanism to connect multiple PIM sparse-mode domains. MSDP allows multicast sources for a group to be known to all rendezvous points (RPs) in different domains. Each PIM-SM domain uses its own RPs and need not depend on RPs in other domains.

An RP in a PIM-SM domain has MSDP peering relationships with MSDP-enabled routers in other domains. Each peering relationship occurs over a TCP connection, which is maintained by the underlying routing system.

MSDP speakers exchange messages called Source Active (SA) messages. When an RP learns about a local active source, typically through a PIM register message, the MSDP process encapsulates the register in an SA message and forwards the information to its peers. The message contains the source and group information for the multicast flow, as well as any encapsulated data. If a neighboring RP has local joiners for the multicast group, the RP installs the S, G route, forwards the encapsulated data contained in the SA message, and sends PIM joins back towards the source. This process describes how a multicast path can be built between domains.

Note

Although you should configure BGP or Multiprotocol BGP for optimal MSDP interdomain operation, this is not considered necessary in the Cisco IOS XR Software implementation. For information about how BGP or Multiprotocol BGP may be used with MSDP, see the MSDP RPF rules listed in the Multicast Source Discovery Protocol (MSDP), Internet Engineering Task Force (IETF) Internet draft.

Cisco IOS XR Software provides support for Internet Group Management Protocol (IGMP) over IPv4.

IGMP provides a means for hosts to indicate which multicast traffic they are interested in and for routers to control and limit the flow of multicast traffic throughout the network. Routers build state by means of IGMP messages; that is, router queries and host reports.

A set of routers and hosts that receive multicast data streams from the same source is called a multicast group. Hosts use IGMP messages to join and leave multicast groups.

Note

IGMP messages use group addresses, which are Class D IP addresses. The high-order four bits of a Class D address are 1110. Host group addresses can be in the range 224.0.0.0 to 239.255.255.255. The address is guaranteed not to be assigned to any group. The address 224.0.0.1 is assigned to all systems on a subnet. The address 224.0.0.2 is assigned to all routers on a subnet.

Functioning of IGMP Routing

The following image "IGMP Singaling" , illustrates two sources, 10.0.0.1 and 10.0.1.1, that are multicasting to group 239.1.1.1.

The receiver wants to receive traffic addressed to group 239.1.1.1 from source 10.0.0.1 but not from source 10.0.1.1.

The host must send an IGMPv3 message containing a list of sources and groups (S, G) that it wants to join and a list of sources and groups (S, G) that it wants to leave. Router C can now use this information to prune traffic from Source 10.0.1.1 so that only Source 10.0.0.1 traffic is being delivered to Router C.

Multicast route statistic feature provides information about the multicast routes. The multicast statistics information includes the rate at which packets are received.

Before enabling multicast route statistics, you must configure an ACL to specify which of the IP route statistics to be captured.

This feature enables selecting a bundle member in the control plane to steer the L2 and L3 multicast traffic traversing over bundle at the egress NP.

This feature brings following benefits:

• Optimizes fabric bandwidth as the member selection is performed in the control plane

• Reduces NP bandwidth and processing as number of OLE replications are less

• Supports bundle member change in MVPN head node with local receiver

In today's broadcast video networks, proprietary transport systems are used to deliver entire channel line-ups to each video branch office. IP based transport network would be a cost efficient/convenient alternative to deliver video services combined with the delivery of other IP based services. (Internet delivery or business services)

By its very nature, broadcast video is a service well-suited to using IP multicast as a more efficient delivery mechanism to reach end customers.

The IP multicast delivery of broadcast video is explained as follows:

1. Encoding devices in digital primary headends, encode one or more video channels into a Moving Pictures Expert Group (MPEG) stream which is carried in the network via IP multicast.

2. Devices at video branch office are configured by the operator to request the desired multicast content via IGMP joins.

3. The network, using PIM-SSM as its multicast routing protocol, routes the multicast stream from the digital primary headend to edge device receivers located in the video branch office. These edge devices could be edge QAM devices which modulate the MPEG stream for an RF frequency, or CMTS for DOCSIS.

This section contains information related to Multicast Label Distribution Protocol (MLDP) and the associated features.

The following MLDP profiles are supported when the router is configured as an edge router:

• Profile 6—VRF MLDP - In-Band Signaling

• Profile 7—Global MLDP In-band Signaling

• Profile 14—MLDP Partitioned MDT P2MP with BGP AD and BGP-C Multicast Signaling

The MLDP Profile 14 is supported when the router is configured as an edge router.

IP based transport network is a cost efficient and convenient alternative to deliver video services combined with the delivery of other IP based services. To deliver IPTV content MLDP Profile 14 also called as the partitioned MDT, is supported when a router is configured as an edge router.

These are the characteristics of the profile 14:

• Customer traffic is SSM.

• Inter-AS Option A, B and C is supported.

• All PEs must have a unique BGP Route Distinguisher (RD) value.

vrf one
 address-family ipv4 unicast
  import route-target
   1:1
  !
  export route-target
   1:1
  !
 !

router pim
 vrf one
  address-family ipv4
   rpf topology route-policy rpf-for-one
   mdt c-multicast-routing bgp
   !
   interface GigabitEthernet0/1/0/0
    enable
   !
  !
 !
!

route-policy rpf-for-one
  set core-tree mldp-partitioned-p2mp
end-policy
!

multicast-routing
 vrf one
  address-family ipv4
   mdt source Loopback0
   mdt partitioned mldp ipv4 p2mp
   rate-per-route
   interface all enable
   bgp auto-discovery mldp
   !
   accounting per-prefix
  !
 !
!

mpls ldp
 mldp
  logging notifications
  address-family ipv4
  !
 !
!

Label Switch Multicast (LSM) is MPLS technology extensions to support multicast using label encapsulation. Next-generation MVPN is based on Multicast Label Distribution Protocol (mLDP), which can be used to build P2MP and MP2MP LSPs through a MPLS network. These LSPs can be used for transporting both IPv4 and IPv6 multicast packets, either in the global table or VPN context.

When router is positioned as the core router running mLDP, it only supports the Profiles 5, 6, 7, 12, 14, and 17 irrespective of the profiles supported on the edge router.

When router is positioned as the edge router running mLDP, it only supports the Profiles 6, 7, and 14.

Note	IPv6 is not supported for profile 10. Also IPv4 SM is not supported for mLDP profiles on an edge router.

For more information about the characteristics of each of the mLDP Profiles,

mpls ldp
 mldp
  logging notifications
  address-family ipv4
  !
 !
!
 

Profile 22 is a mVPN profile used for multicast traffic engineering using RSVP-TE P2MP. RSVP-TE is used to establish MPLS transport LSPs when there are traffic engineering requirements. The Default MDT consists of a full mesh of P2MP-TE tree. The P2MP tunnels are P2MP-TE auto-tunnels. PIM is used for C-Multicast signaling.

These are the characteristics of this profile:

• Dynamic P2MP-TE tunnels with BGP C-Multicast routing.

• All UMH options are supported.

• Default and Data MDT are supported.

• Customer traffic can be SSM.

vrf one
 address-family ipv4 unicast
  import route-target
   1:1
  !
  export route-target
   1:1
  !
 !

router pim
 vrf one
  address-family ipv4
   rpf topology route-policy rpf-vrf-one
   mdt c-multicast-routing bgp
   interface GigabitEthernet0/0/0/1.100
    enable

route-policy rpf-vrf-one
  set core-tree p2mp-te-default
end-policy

multicast-routing
 vrf one
  address-family ipv4
   mdt source Loopback0
   mdt default p2mp-te
   rate-per-route
   interface all enable
   mdt data p2mp-te 100
   bgp auto-discovery p2mp-te
   !
   accounting per-prefix

ipv4 unnumbered mpls traffic-eng Loopback0

mpls traffic-eng
 interface GigabitEthernet0/0/0/0
 !
 interface GigabitEthernet0/0/0/2
 !
  auto-tunnel p2mp
  tunnel-id min 1000 max 2000

Router# show mrib vrf p22_20 route detail 
IP Multicast Routing Information Base

Entry flags: L - Domain-Local Source, E - External Source to the Domain,
    C - Directly-Connected Check, S - Signal, IA - Inherit Accep
    IF - Inherit From, D - Drop, ME - MDT Encap, EID - Encap ID,
    MD - MDT Decap, MT - MDT Threshold Crossed, MH - MDT interface handle
    CD - Conditional Decap, MPLS - MPLS Decap, EX - Extranet
    MoFE - MoFRR Enabled, MoFS - MoFRR State, MoFP - MoFRR Primary
    MoFB - MoFRR Backup, RPFID - RPF ID Set, X - VXLAN
Interface flags: F - Forward, A - Accept, IC - Internal Copy
    NS - Negate Signal, DP - Don't Preserve, SP - Signal Present,
   II - Internal Interest, ID - Internal Disinterest, LI - Local Interest,
    LD - Local Disinterest, DI - Decapsulation Interface
   EI - Encapsulation Interface, MI - MDT Interface, LVIF - MPLS Encap,
   EX - Extranet, A2 - Secondary Accept, MT - MDT Threshold Crossed,
   MA - Data MDT Assigned, LMI - mLDP MDT Interface, TMI - P2MP-TE MDT Interface
 IRMI - IR MDT Interface, TRMI - TREE SID MDT Interface, MH - Multihome Interface

(80.0.0.11,232.1.1.1) Ver: 0xb009 RPF nbr: 80.0.0.11 Flags: RPF EID, 
 PD: Slotmask: 0x0
     MGID: 592
  Up: 00:07:14
  RPF-ID: 0, Encap-ID: 262145
  Incoming Interface List
    TenGigE0/1/0/1.2 Flags: A, Up: 00:07:14
  Outgoing Interface List
    Tmdtp22/ssm/v4/vrf2 Flags: F TMI, Up: 00:07:14, Head LSM-ID: 0x4000360

To configure VRF MLDP in-band signaling (Profile 6) on edge routers, you must complete the following tasks:

1. Assign a route policy in PIM to select a reverse-path forwarding (RPF) topology.

2. Configure route policy to set the Multicast Distribution Tree (MDT) type to MLDP inband.

3. Enable MLDP-inband signaling in multicast routing.

4. Enable MPLS for MLDP.

RP/0/RP0/CPU0:router(config)#router pim
RP/0/RP0/CPU0:router(config-pim)#vrf one
RP/0/RP0/CPU0:router(config-pim-one)#address-family ipv4
RP/0/RP0/CPU0:router(config-pim-one-ipv4)#rpf topology route-policy rpf-vrf-one

RP/0/RP0/CPU0:router(config)#route-policy rpf-vrf-one
RP/0/RP0/CPU0:router(config-rpl)#set core-tree mldp-inband
RP/0/RP0/CPU0:router(config-rpl)#end-policy
 

RP/0/RP0/CPU0:router(config)#multicast-routing
RP/0/RP0/CPU0:router(config-mcast)#vrf one
RP/0/RP0/CPU0:router(config-mcast-one)#address-family ipv4
RP/0/RP0/CPU0:router(config-mcast-one-ipv4)#mdt source loopback 0
RP/0/RP0/CPU0:router(config-mcast-one-ipv4)#mdt mldp in-band-signaling ipv4
RP/0/RP0/CPU0:router(config-mcast-one-ipv4)#interface all enable

RP/0/RP0/CPU0:router(config)#mpls ldp
RP/0/RP0/CPU0:router(config-ldp)#mldp

To configure global MLDP in-band signaling (Profile 7) on edge routers, you must complete the following tasks:

1. Assign a route policy in PIM to select a reverse-path forwarding (RPF) topology.

2. Configure route policy to set the MDT type to MLDP Inband.

3. Enable MLDP inband signaling in multicast routing.

4. Enable MPLS MLDP.

RP/0/RP0/CPU0:router(config)#router pim
RP/0/RP0/CPU0:router(config-pim)#address-family ipv4
RP/0/RP0/CPU0:router(config-pim-default-ipv4)#rpf topology route-policy rpf-global
RP/0/RP0/CPU0:router(config-pim-default-ipv4)#interface TenGigE 0/11/0/1
RP/0/RP0/CPU0:router(config-pim-ipv4-if)#enable

RP/0/RP0/CPU0:router(config)#route-policy rpf-global
RP/0/RP0/CPU0:router(config-rpl)#set core-tree mldp-inband
RP/0/RP0/CPU0:router(config-rpl)#end-policy
 

RP/0/RP0/CPU0:router(config)#multicast-routing
RP/0/RP0/CPU0:router(config-mcast)#address-family ipv4
RP/0/RP0/CPU0:router(config-mcast-default-ipv4)#interface loopback 0
RP/0/RP0/CPU0:router(config-mcast-default-ipv4-if)#enable
RP/0/RP0/CPU0:router(config-mcast-default-ipv4-if)#exit
RP/0/RP0/CPU0:router(config-mcast-default-ipv4)#mdt source loopback 0
RP/0/RP0/CPU0:router(config-mcast-default-ipv4)#mdt mldp in-band-signaling ipv4
RP/0/RP0/CPU0:router(config-mcast-default-ipv4)#interface all enable

RP/0/RP0/CPU0:router(config)#mpls ldp
RP/0/RP0/CPU0:router(config-ldp)#mldp

The following restriction applies to the configuration of MVPN profile:

• A router being Route Reflector (RR) and Provider Edge (PE) at that same time for BGP mVPN implementation is not supported, a type 7 and type 6 IPv4 mVPN route is not advertised by a RR, which is also a PE router, if the PE router has the VRF locally configured and when there is a local receiver.

  Use full mesh for iBGP mVPN address-family or elect any core (P) router to be the RR.

This section provides profile-wise configuration examples for the various MVPN profiles.

Use the following commands to verify the MLDP configuration on edge routers.

To check the MLDP neighbors, use the show mpls mldp neighbor command.

RP/0/RP0/CPU0:Head# show mpls mldp neighbors 
mLDP neighbor database
MLDP peer ID      : 2.2.2.2:0, uptime 07:47:59 Up, 
  Capabilities     : GR, Typed Wildcard FEC, P2MP, MP2MP
  Target Adj       : No
  Upstream count   : 1
  Branch count     : 1
  LDP GR           : Enabled
                   : Instance: 1
  Label map timer  : never
  Policy filter in : 
  Path count       : 1
  Path(s)          : 12.1.1.2          TenGigE0/11/0/1 LDP 
  Adj list         : 12.1.1.2          TenGigE0/11/0/1
  Peer addr list   : 2.25.32.2        
                   : 2.2.2.2          
                   : 11.1.1.1         
                   : 12.1.1.2         
                   : 13.10.1.1      

To display the contents of the Label Information Base (LIB), use the show mpls mldp bindings command.

RP/0/RP0/CPU0:Head#show mpls mldp bindings 
mLDP MPLS Bindings database
 
LSP-ID: 0x00001 Paths: 7 Flags:
0x00001 P2MP   5.5.5.5 [vpnv6 1:1 2015:1:1::3 ff3e::1]
   Local Label: 70009
   Remote Label: 64018 NH: 12.1.1.2 Inft: TenGigE0/11/0/1
   Remote Label: 64022 NH: 50.1.1.1 Inft: TenGigE0/11/0/1
   Remote Label: 30002 NH: 30.10.1.2 Inft: Bundle-Ether56
   Remote Label: 64023 NH: 60.1.1.2 Inft: HundredGigE0/0/1/1
   Remote Label: 64024 NH: 70.1.1.1 Inft: TenGigE0/11/0/2
   Remote Label: 64022 NH: 40.1.1.1 Inft: TenGigE0/11/0/3

To display the MLDP event traces, use the show mpls mldp trace command.

RP/0/RP0/CPU0:Head#show mpls mldp trace 
3535 wrapping entries (631040 possible, 35584 allocated, 0 filtered, 3535 total)
May 30 23:30:21.121 MLDP GLO 0/RP0/CPU0 t6746 GEN  : Trace pre-init iox success 
May 30 23:30:21.121 MLDP GLO 0/RP0/CPU0 t6746 GEN  : Debug pre-init iox success 
May 30 23:30:21.121 MLDP GLO 0/RP0/CPU0 t6746 GEN  : API pre-init iox success 
May 30 23:30:21.121 MLDP GLO 0/RP0/CPU0 t6746 GEN  : Bitfield pre-init iox success 
May 31 12:08:39.465 MLDP GLO 0/RP0/CPU0 t6746 GEN  : mldp_evm 0x563de8f01698 allocated
May 31 12:08:39.465 MLDP GLO 0/RP0/CPU0 t6746 GEN  : EVM init iox success 
May 31 12:08:39.472 MLDP GLO 0/RP0/CPU0 t6746 GEN  : Registered EDM on active success
May 31 12:08:39.472 MLDP GLO 0/RP0/CPU0 t6746 GEN  : EDM Ac/St init iox again 
May 31 12:08:39.472 MLDP GLO 0/RP0/CPU0 t6746 GEN  : Registered EDM Location on active success
May 31 12:08:39.472 MLDP GLO 0/RP0/CPU0 t6746 GEN  : EDM Loc init iox success 
May 31 12:08:39.475 MLDP GLO 0/RP0/CPU0 t6746 GEN  : LMRIB init iox success 
May 31 12:08:39.475 MLDP GLO 0/RP0/CPU0 t18944 MRIB : MRIB connection established
May 31 12:08:39.475 MLDP GLO 0/RP0/CPU0 t6746 GEN  : Interface manager init iox success 
May 31 12:08:39.475 MLDP GLO 0/RP0/CPU0 t6746 GEN  : Async init iox success 
May 31 12:08:39.475 MLDP GLO 0/RP0/CPU0 t6746 GEN  : Boolean init iox success 
May 31 12:08:39.475 MLDP GLO 0/RP0/CPU0 t6746 GEN  : Timers init iox success 
May 31 12:08:39.479 MLDP GLO 0/RP0/CPU0 t6746 GEN  : RUMP init iox success 
May 31 12:08:39.479 MLDP GLO 0/RP0/CPU0 t6746 GEN  : Chunks init iox success 
May 31 12:08:39.509 MLDP ERR 0/RP0/CPU0 t6746 RIB  : RIB not ready
May 31 12:08:39.509 MLDP ERR 0/RP0/CPU0 t6746 RIB  : RIB not ready
May 31 12:08:39.512 MLDP GLO 0/RP0/CPU0 t6746 GEN  : mldp_ens_event_ctx_chunk is NULL
May 31 12:08:39.512 MLDP GLO 0/RP0/CPU0 t6746 GEN  : Context Table init iox success 
May 31 12:08:39.512 MLDP GLO 0/RP0/CPU0 t6746 GEN  : mldp_rib_main_evm 0x563de8fd23e8 allocated
May 31 12:08:39.512 MLDP GLO 0/RP0/CPU0 t6746 GEN  : RIB Thread EVM init rib success 
May 31 12:08:39.512 MLDP GLO 0/RP0/CPU0 t6746 GEN  : RIB Thread Chunk init rib success 
May 31 12:08:39.512 MLDP GLO 0/RP0/CPU0 t6746 GEN  : RIB Thread queue init rib success 
May 31 12:08:39.512 MLDP GLO 0/RP0/CPU0 t6746 RIB  : Bound to RIB, fd: 354