Dell PowerSwitch S4820T Configuration Guide for the S4820T System 9.14.1.0 - Page 186
MBGP for IPv4 MulticastBGP Address Family modelIPv4 and IPv6 address family, Implement BGP with Dell EMC Networking OS, Additional Path (Add-Path) Support
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Page 186 highlights
MBGP uses either an IPv4 address configured on the interface (which is used to establish the IPv6 session) or a stable IPv4 address that is available in the box as the next-hop address. As a result, while advertising an IPv6 network, exchange of IPv4 routes does not lead to martian next-hop message logs. NOTE: It is possible to configure BGP peers that exchange both unicast and multicast network layer reachability information (NLRI), but you cannot connect multiprotocol BGP with BGP. Therefore, you cannot redistribute multiprotocol BGP routes into BGP. MBGP for IPv4 Multicast PIM feature uses IPv4 multicast routing for data distribution. MBGP provides a link that is dedicated specific to multicast traffic. MBGP also allows a unicast routing apart from the multicast routing. A multicast routing protocol, such as PIM, uses both the unicast and multicast BGP database to form a routing table for unicast and multicast. You can configure BGP peers that exchange both unicast and multicast Network Layer Reachability Information (NLRI) in which MBGP routes is redistributed into BGP. The default is IPv4 unicast. BGP Address Family model Dell EMC Networking OS supports BGP address family identifier (AFI) with MBGP to provide scalability for multiple AFI and subsequent address family identifier (SAFI) configurations. MBGP carries routing information for address families (IPv4 and IPv6) of multiple networklayer protocols. Each address family has a separated BGP database, so that you can configure BGP policy based on address family. IPv4 and IPv6 address family The IPv4 address family configuration in Dell EMC Networking OS is used for identifying routing sessions for protocols that use IPv4 address. You can specify multicast within the IPv4 address family. The default of address family configuration is IPv4 unicast. You can configure the VRF instances for IPv4 address family configuration. The IPv6 address family configuration is used for identifying routing sessions for protocols that use IPv6 address. You can specify unicast within the IPv6 address family. You can configure the VRF instances for IPv6 address family configuration. Implement BGP with Dell EMC Networking OS The following sections describe how to implement BGP on Dell EMC Networking OS. Additional Path (Add-Path) Support The add-path feature reduces convergence times by advertising multiple paths to its peers for the same address prefix without replacing existing paths with new ones. By default, a BGP speaker advertises only the best path to its peers for a given address prefix. If the best path becomes unavailable, the BGP speaker withdraws its path from its local RIB and recalculates a new best path. This situation requires both IGP and BGP convergence and can be a lengthy process. BGP add-path also helps switchover to the next new best path when the current best path is unavailable. 186 Border Gateway Protocol version 4 (BGPv4)
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