BGP MDT address family sessions

Updated: June 9, 2026

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Describes the functionality of BGP MDT address family sessions that enable exchange of IPv4 multicast routing information using MDT SAFI, supporting multicast VPNs and route redistribution across protocols and VRFs.

A multicast distribution tree (MDT) address family session in BGP is a feature that

enables you to exchange IPv4 multicast routing information using the MDT subaddress family identifier (SAFI)
supports multicast virtual private networks (MVPN), including both IPv4 and IPv6 deployments, and
allows you to redistribute multicast routing information across multiple protocols and VRFs.

This feature is essential for service providers and enterprises that deploy multicast VPNs over BGP-based core networks.

Configure a BGP MDT address family session

Set up a BGP session for IPv4 MDT, which can also support multicast VPNv4 and VPNv6 distribution.

Before you begin

Ensure you have decided on the autonomous system number (ASN) and router ID.
Identify the interface or loopback address to use as the update source.

Procedure

	1.	Enter BGP configuration mode for your autonomous system. Example: `Router# configure Router(config)# router bgp 120`
	2.	Enable the MDT address family. If you are configuring multicast MVPN, also enable the unicast and VPN address families. Example: `Router(config-vrf)# address-family ipv4 unicast Router(config-bgp-af)# exit Router(config-bgp)# address-family vpnv4 unicast Router(config-bgp-af)# exit Router(config-bgp)# address-family ipv4 mdt Router(config-bgp-af)# exit`
	3.	Configure the BGP neighbor, specify its remote AS, and set the update source. Example: `Router(config-bgp)# neighbor 172.168.40.24 Router(config-bgp-nbr)# remote-as 2002 Router(config-bgp-nbr)# update-source loopback 0`
	4.	Activate the required address families for the neighbor. Example: `Router(config-bgp-nbr)# address-family ipv4 unicast Router(config-bgp-nbr-af)# exit Router(config-bgp-nbr)# address-family vpnv4 unicast Router(config-bgp-nbr-af)# exit Router(config-bgp)# address-family ipv4 mdt Router(config-bgp-af)# exit`
	5.	If you are configuring multicast MVPN, create a VRF instance and configure a route distinguisher (RD). Example: `Router(config-bgp)# vrf vpn1 Router(config-bgp-vrf)# rd 1:1`
	6.	Within the VRF, redistribute routes from another routing protocol, such as EIGRP or OSPF, into BGP. Example: `Router(config-bgp-vrf)# address-family ipv4 unicast Router(config-bgp-vrf-af)# redistribute eigrp 23`
	7.	Commit the configuration changes. Example: `Router(config-bgp-vrf-af)#commit`
	8.	Run the show running-config command to verify the configuration. Example: `Router# show running-config router bgp 120 address-family ipv4 mdt ! address-family vpnv4 unicast ! vrf vpn1 rd 1:1 address-family ipv4 unicast redistribute eigrp 23 ! ! neighbor 172.168.40.24 remote-as 2002 update-source Loopback0 address-family ipv4 mdt ! address-family vpnv4 unicast ! address-family ipv4 unicast ! !`

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BGP MDT address family sessions

Configure a BGP MDT address family session

Before you begin

Procedure

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