Users Guide

Match a Clause with a Continue Clause
The continue feature can exist without a match clause.
Without a match clause, the continue clause executes and jumps to the specied route-map entry. With a match clause and a
continue clause, the match clause executes rst and the continue clause next in a specied route map entry. The continue clause
launches only after a successful match. The behavior is:
• A successful match with a continue clause—the route map executes the set clauses and then goes to the specied route map
entry after execution of the continue clause.
• If the next route map entry contains a continue clause, the route map executes the continue clause if a successful match occurs.
• If the next route map entry does not contain a continue clause, the route map evaluates normally. If a match does not occur, the
route map does not continue and falls-through to the next sequence number, if one exists
Set a Clause with a Continue Clause
If the route-map entry contains sets with the continue clause, the set actions operation is performed rst followed by the continue
clause jump to the specied route map entry.
• If a set actions operation occurs in the rst route map entry and then the same set action occurs with a dierent value in a
subsequent route map entry, the last set of actions overrides the previous set of actions with the same set command.
• If the set community additive and set as-path prepend commands are congured, the communities and AS
numbers are prepended.
Enabling MBGP Congurations
Multiprotocol BGP (MBGP) is an enhanced BGP that carries IP multicast routes. BGP carries two sets of routes: one set for unicast
routing and one set for multicast routing. The routes associated with multicast routing are used by the protocol independent
multicast (PIM) to build data distribution trees.
Dell Networking OS MBGP is implemented per RFC 1858. You can enable the MBGP feature per router and/or per peer/peer-group.
The default is IPv4 Unicast routes.
When you congure a peer to support IPv4 multicast, Dell 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 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 Networking OS Command Line Interface Reference
Guide.
• Enables support for the IPv4 multicast family on the BGP node.
CONFIG-ROUTER-BGP mode
address family ipv4 multicast
• Enable IPv4 multicast support on a BGP neighbor/peer group.
CONFIG-ROUTER-BGP-AF (Address Family) mode
neighbor [ip-address | peer-group-name] activate
Border Gateway Protocol IPv4 (BGPv4)
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