BGP Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

BGP Default Limits and Multiprotocol Address Handling

Updated: February 28, 2026

Overview

Explains BGP default limits and multiprotocol address handling, including advertising IPv4 routes over IPv6 networks and configuring MDT address family sessions. Covers default peer and prefix limits, IPv4 NLRI advertisement with IPv6 next hops, and BGP MDT sessions with examples.

Learn how to manage BGP limits and set up advanced routing, including IPv4 over IPv6 and MDT sessions for different VRFs.

BGP default peer and prefix limits

Provides guidelines for BGP default limits that restrict maximum peers and prefixes to prevent resource depletion, control scaling, and maintain router stability. Describes default and configurable limits and how BGP enforces these limits to protect router resources.

IPv4 NLRI advertisement with IPv6 next hops in multiprotocol BGP networks

Describes the functionality of advertising IPv4 NLRI with IPv6 next hops to enable communication across mixed-protocol networks. Explains support for default and non-default VRFs and how this feature increases network flexibility by allowing IPv4 routes to use IPv6 next hops.

BGP MDT address family sessions

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.

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