What is advertisement interval in BGP

[Aoi]

Hi.

I need some help on the command

neighbor XXXXX advertisement-interval

in BGP.
Does this send update messages to the peers with the specified intervals? 

My understanding was there was a certain amount of time (default value) depending on which devices used and this command was to update that value. However, I am not seeing any updates being sent to my peers despite this command or even without this.

Thanks

[Torbjørn]

The advertisement interval(Minimum Route Advertisement Interval in the RFC) is the time minimum interval between BGP advertisements/withdrawals of a prefix to a given BGP neighbour. This is intended to make the routing domain more stable and less prone to flapping routes. The default value for eBGP neighbors is 30 seconds and 5 seconds 0 seconds for iBGP.

[MHM Cisco World]

Add prefix 

And then check update after interval time.

Thanks A Lot
MHM

[David Ruess · Accepted solution]

Hello,

Updates are triggered when the BGP peer learns of a new network or has to modify an existing network (to include removal). This does not indicate that it will periodically send out updates of its advertised networks based on the timer you configure. This is used for when you're receiving a bunch of updates and instead of constantly sending updates to your peers you wait the interval after sending the first round of updates. For iBGP peers it is immediate and eBGP peers will wait 30 seconds between sending subsequent updates.

For iBGP neighbors this defaults to 0 seconds
For eBGP neighbors this defaults to 30 seconds

(at least for Cisco IOS)

You can see in the output here the defaults:

R7#sh ip bgp neighbors 
BGP neighbor is 1.1.1.1, remote AS 100, internal link (iBGP neighbor)
Inherits from template iBGP for session parameters
BGP version 4, remote router ID 11.11.11.11
BGP state = Established, up for 21:37:15
Last read 00:00:01, last write 00:00:01, hold time is 30, keepalive interval is 5 seconds
Configured hold time is 30, keepalive interval is 5 seconds
Minimum holdtime from neighbor is 20 seconds
Neighbor sessions:
1 active, is not multisession capable (disabled)
Neighbor capabilities:
Route refresh: advertised and received(new)
Four-octets ASN Capability: advertised and received
Address family IPv4 Unicast: advertised and received
Enhanced Refresh Capability: advertised and received
Multisession Capability: 
Stateful switchover support enabled: NO for session 1
Message statistics:
InQ depth is 0
OutQ depth is 0

Sent Rcvd
Opens: 1 1
Notifications: 0 0
Updates: 1 1
Keepalives: 15204 15093
Route Refresh: 0 0
Total: 15206 15095
Do log neighbor state changes (via global configuration)
Default minimum time between advertisement runs is 0 seconds

***OUTPUT REMOVED FOR BREVITY***

BGP neighbor is 4.4.4.4, remote AS 400, external link (eBGP neighbor)
BGP version 4, remote router ID 4.4.4.4
BGP state = Established, up for 00:01:01
Last read 00:00:10, last write 00:00:10, hold time is 180, keepalive interval is 60 seconds
Neighbor sessions:
1 active, is not multisession capable (disabled)
Neighbor capabilities:
Route refresh: advertised and received(new)
Four-octets ASN Capability: advertised and received
Address family IPv4 Unicast: advertised and received
Enhanced Refresh Capability: advertised and received
Multisession Capability: 
Stateful switchover support enabled: NO for session 1
Message statistics:
InQ depth is 0
OutQ depth is 0

Sent Rcvd
Opens: 1 1
Notifications: 0 0
Updates: 1 1
Keepalives: 3 3
Route Refresh: 0 0
Total: 5 5
Do log neighbor state changes (via global configuration)
Default minimum time between advertisement runs is 30 seconds

***OUTPUT REMOVED FOR BREVITY***

R7#

Hope this helps

-David