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neighbor {IP address | peer-group-name} allowas-in number
○ Peer Group Name: 16 characters.
○ Number: from 1 through 10.
Format: IP Address: A.B.C.D.
You must Configuring Peer Groups before assigning it to an AS.
The lines shown in bold are the number of times ASN 65123 can appear in the AS path (allows–in 9).
To disable this feature, use the no neighbor allow-as in number command in CONFIGURATION ROUTER BGP mode.
Dell(conf-router_bgp)#show conf
!
router bgp 65123
bgp router-id 192.168.10.2
network 10.10.21.0/24
network 10.10.32.0/24
network 100.10.92.0/24
network 192.168.10.0/24
bgp four-octet-as-support
neighbor 10.10.21.1 remote-as 65123
neighbor 10.10.21.1 filter-list Name in
neighbor 10.10.21.1 no shutdown
neighbor 10.10.32.3 remote-as 65123
neighbor 10.10.32.3 no shutdown
neighbor 100.10.92.9 remote-as 65192
neighbor 100.10.92.9 local-as 6500
neighbor 100.10.92.9 no shutdown
neighbor 192.168.10.1 remote-as 65123
neighbor 192.168.10.1 update-source Loopback 0
neighbor 192.168.10.1 no shutdown
neighbor 192.168.12.2 remote-as 65123
Enabling Graceful Restart
To lessen the negative effects of a BGP restart, use the graceful restart feature.
Dell Networking OS advertises support for this feature to BGP neighbors through a capability advertisement. You can enable
graceful restart by router and/or by peer or peer group.
NOTE: By default, BGP graceful restart is disabled.
The default role for BGP is as a receiving or restarting peer. If you enable BGP, when a peer that supports graceful restart
resumes operating, Dell Networking OS performs the following tasks:
● Continues saving routes received from the peer if the peer advertised it had graceful restart capability. Continues forwarding
traffic to the peer.
● Flags routes from the peer as Stale and sets a timer to delete them if the peer does not perform a graceful restart.
● Deletes all routes from the peer if forwarding state information is not saved.
● Speeds convergence by advertising a special update packet known as an end-of-RIB marker. This marker indicates that the
peer has been updated with all routes in the local RIB.
If you configure your system to do so, Dell Networking OS can perform the following actions during a hot failover:
● Save all forwarding information base (FIB) and content addressable memory (CAM) entries on the line card and continue
forwarding traffic while the secondary route processor module (RPM) is coming online.
● Advertise to all BGP neighbors and peer-groups that the forwarding state of all routes has been saved. This prompts all
peers to continue saving the routes they receive and to continue forwarding traffic.
● Bring the secondary RPM online as the primary and re-open sessions with all peers operating in No Shutdown mode.
● Defer best path selection for a certain amount of time. This helps optimize path selection and results in fewer updates being
sent out.
To enable graceful restart, use the configure router bgp graceful-restart command.
● Enable graceful restart for the BGP node.
CONFIG-ROUTER-BGP mode
bgp graceful-restart
● Set a maximum restart time for all peers.
Border Gateway Protocol IPv4 (BGPv4)
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