Dell PowerSwitch S4820T 9.50.1 Configuration Guide for the S4820T System - Page 199
Enabling BGP, Route Flap Damping Parameters
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By default, Dell Networking OS compares the MED attribute on different paths from within the same AS (the bgp always-compare-med command is not enabled). NOTE: In Dell Networking OS, all newly configured neighbors and peer groups are disabled. To enable a neighbor or peer group, enter the neighbor {ip-address | peer-group-name} no shutdown command. The following table displays the default values for BGP on Dell Networking OS. Table 9. BGP Default Values Item Default BGP Neighbor Adjacency changes All BGP neighbor changes are logged. Fast External Fallover feature Disabled Graceful Restart feature Disabled Local preference 100 MED Route Flap Damping Parameters 0 half-life = 15 minutes reuse = 750 suppress = 2000 max-suppress-time = 60 minutes Distance external distance = 20 internal distance = 200 local distance = 200 Timers keepalive = 60 seconds holdtime = 180 seconds Add-path Disabled Enabling BGP By default, BGP is not enabled on the system. Dell Networking OS supports one autonomous system (AS) and assigns the AS number (ASN). To establish BGP sessions and route traffic, configure at least one BGP neighbor or peer. In BGP, routers with an established TCP connection are called neighbors or peers. After a connection is established, the neighbors exchange full BGP routing tables with incremental updates afterward. In addition, neighbors exchange KEEPALIVE messages to maintain the connection. In BGP, neighbor routers or peers can be classified as internal or external. External BGP peers must be connected physically to one another (unless you enable the EBGP multihop feature), while internal BGP peers do not need to be directly connected. The IP address of an EBGP neighbor is usually the IP address of the interface directly connected to the router. First, the BGP process determines if all internal BGP peers are reachable, then it determines which peers outside the AS are reachable. Border Gateway Protocol IPv4 (BGPv4) 199
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