Concept Guide

When you congure a peer to support IPv4 multicast, Dell EMC Networking OS takes the following actions:
• Send a capacity advertisement to the peer in the BGP Open message specifying IPv4 multicast as a supported AFI/SAFI (Subsequent
Address Family Identier).
• If the corresponding capability is received in the peer’s Open message, BGP marks the peer as supporting the AFI/SAFI.
• When exchanging updates with the peer, BGP sends and receives IPv4 multicast routes if the peer is marked as supporting that AFI/
SAFI.
• Exchange of IPv4 multicast route information occurs through the use of two new attributes called MP_REACH_NLRI and
MP_UNREACH_NLRI, for feasible and withdrawn routes, respectively.
• If the peer has not been activated in any AFI/SAFI, the peer remains in Idle state.
Most Dell EMC Networking OS BGP IPv4 unicast commands are extended to support the IPv4 multicast RIB using extra options to the
command. For a detailed description of the MBGP commands, refer to the Dell EMC Networking OS Command Line Interface Reference
Guide.
Congure IPv6 NH Automatically for IPv6 Prex Advertised
over IPv4 Neighbor
You can congure the system to pick the next hop IPv6 address dynamically for IPv6 prex advertised over an IPv4 neighbor congured
under IPv6 address family. If there is no IPv6 address congured on the local interface, the system uses the IPv4 mapped IPv6 address. If
there are multiple IPv6 addresses congured on the interface, the system uses the lowest IPv6 address congured on that interface. If the
conguration is already present and a new IPv6 address, which is lower than the lowest existing address, is assigned to one of the peer
interfaces, that address is not used as the NH until you ap the interface manually.
Figure 24. Congure IPv6 NH to advertise IPv6 prex over IPv4 neighbor
To enable BGP to pick the next hop IPv6 address automatically for IPv6 prex advertised over an IPv4 neighbor, use the following
commands.
• Enable the system to pick the next hop IPv6 address dynamically for IPv6 prex advertised over an IPv4 neighbor.
ROUTER-BGP mode mode
neighbor {ip–address | peer-group-name} auto-local-address
Enter either the neighbor IP address or the name of the peer group.
NOTE
: If outbound policy is applied along with auto-local-address enabled, then policy takes precedence.
Example conguration of BGP to automatically pick IPv6 address automatically for IPv6 prex advertised over an IPv4 neighbor
The following example conguration demonstrates how to congure BGP to automatically pick IPv6 address for IPv6 prex advertised over
an IPv4 neighbor.
Example conguration performed in R1
DellEMC# configure terminal
DellEMC(conf)# router bgp 655
Border Gateway Protocol version 4 (BGPv4)
225