Users Guide

1362 BGP
Routing must be enabled to enable Dell EMC Networking BGP. Both the AS
number and the router ID are required to be configured. Enabling of BGP is
automatic when the AS number and router ID are configured. The no enable
command may be used to temporarily disable BGP without removing the
BGP configuration.
Autonomous Systems
Dell EMC Networking BGP supports both exterior routing (eBGP) between
autonomous systems (inter-AS) and interior routing within an AS (iBGP).
Dell EMC Networking BGP is suitable for use in enterprise and data center
deployments. Dell EMC Networking switches do not have sufficient capacity
to hold a full Internet routing table.
Dell EMC Networking supports BGP version 4 with both 2-byte and 4-byte
Autonomous System Numbers (ASN). An autonomous system number is a
globally unique identifier for a group of IP networks that has a single, clearly
defined external routing policy.
Graceful Restart
BGP supports graceful restart per RFC 4724. When configured in graceful
restart aware mode, the router saves the route table contents prior to an
operator-initiated restart.
BGP Operations
Decision Process Overview
The BGP decision process is logic that applies inbound policy to routing
information from peers, computes routes, and advertises routes to peers.
Figure 38-1 shows an overview of the decision process. BGP parses incoming
UPDATE messages, storing routing information in Adj RIB-In. Phase 1 of the
decision process applies inbound policy to routes in Adj RIB In. Routes that
pass inbound policy are copied to Accept-RIB-In and LOCAL_PREF is set.
BGP uses the routing table to resolve a BGP next hop to a local next hop.
Locally originated routes (those configured with the network command or
redistributed from another protocol) go directly to Accept-RIB-In. Phase 2 of
the decision process selects the best route to each destination in Accept-RIB-
In. Each best route is stored in the local RIB and given to RTO. Phase 3 of the