Incremental & triggered update || OSPF ||

[Umesh Prajapati11238]

Hi everyone,

I am a little bit confused that what is difference between incremental & triggered updates in OSPF.

Please explain anyone in layman's terms.

Regards,

Umesh

[MHM Cisco World]

If I am right  
incremental & triggered updates in OSPF
incremental, each LSA has age time, when it reach the router as the origin router of this LSA  update it LSA "you will see the Seq number change meaning it update"


triggered update 
any change to LSA before the age time, the router as the origin router of this LSA update it LSA "you will see the Seq number change meaning it update"

[MHM Cisco World]

small Lab for trigger Update 
in R1 I have two LO 
1.1.1.1 & 11.11.11.11
this show ip ospf db 
and packet capture show the LSA-1 with three prefix 1.1.1.1 11.11.11.11 and 100.0.0.0
we see the Seq number 0x80000005
this LSA normally age after 30 min 
but we trigger R1 to flood it LSA by shut down the LO 11.11.11.11

this show ip ospf db and packet capture, 
you see Seq 0X80000006 <- it must be higher 
also see the LSA-1 contain now only two prefix 1.1.1.1 and 100.0.0.0

Seq check
1- if the R2 receive Seq lower than it have in DB then it ignore the update 
2-if the R2 receive Seq higher than it have in DB then it will accept update

[Joseph W. Doherty]

Hmm, don't recall those terms being used for OSPF, more RIP like, I believe.  You might find this thread of interest: https://community.cisco.com/t5/routing/incremental-updates/td-p/1556315