Administrator Guide

Item Default
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. The Dell Networking OS supports one autonomous system (AS) and assigns the AS number
(ASN).
To establish BGP sessions and route trac, congure 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 classied 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.
NOTE
: Sample Congurations for enabling BGP routers are found at the end of this
chapter.
1 Assign an AS number and enter ROUTER BGP mode.
CONFIGURATION mode
router bgp as-number
• as-number: from 0 to 65535 (2 Byte) or from 1 to 4294967295 (4 Byte) or 0.1 to 65535.65535 (Dotted format).
Only one AS is supported per system.
NOTE
: If you enter a 4-Byte AS number, 4-Byte AS support is enabled automatically.
a Enable 4-Byte support for the BGP process.
NOTE
: This command is OPTIONAL. Enable if you want to use 4-Byte AS numbers or if you support AS4
number representation.
CONFIG-ROUTER-BGP mode
bgp four-octet-as-support
NOTE
: Use it only if you support 4-Byte AS numbers or if you support AS4 number representation. If you are
supporting 4-Byte ASNs, enable this command.
Disable 4-Byte support and return to the default 2-Byte format by using the no bgp four-octet-as-support command.
You cannot disable 4-Byte support if you currently have a 4-Byte ASN congured.
Disabling 4-Byte AS numbers also disables ASDOT and ASDOT+ number representation. All AS numbers are displayed in
ASPLAIN format.
Border Gateway Protocol IPv4 (BGPv4)
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