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Beginner

OSPF LSA Refresh Interval

Can we change the LSA Refresh interval(30mins default) in OSPF or not?
 
P.S. I have gone through a lot of literature & googled it but can't find a clear answer (some say yes & some say no) ... & im confused now. So, plz if someone can answer it simply.
Everyone's tags (3)
1 ACCEPTED SOLUTION

Accepted Solutions

Re: OSPF LSA Refresh Interval


@xaviar188 wrote:
Can we change the LSA Refresh interval(30mins default) in OSPF or not?
 
P.S. I have gone through a lot of literature & googled it but can't find a clear answer (some say yes & some say no) ... & im confused now. So, plz if someone can answer it simply.

LSA refresh timer / interval can be changed in some vendors while it cannot be changed in some other vendors. For example, we can change / Tune this interval in Juniper while we cannot change it in case of Cisco Equipment. Hope, it will clarify your question.


Regards,
Waqas Karim (CCIE)
8 REPLIES 8
Beginner

Re: OSPF LSA Refresh Interval

Thanks luis. I have already gone through these & many other literature but couldn't get clear answer to my question i.e. Can we change the LSA Refresh interval(30mins default) in OSPF or not?
Hall of Fame Expert

Re: OSPF LSA Refresh Interval

Hello Xaviar,

from the links provided by the other colleague and with some other web search we can say the following:

LSA refresh time interval can be changed in some vendor implementations (Juniper for example).

Cisco routers look like are missing this capability.

 

However, to achieve better scalability in OSPF rather then changing the LSA refresh timer it is important to use the functionality of LSA group pacing described here:

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_ospf/configuration/xe-16-9/iro-xe-16-9-book/iro-cfg.html#GUID-CF9E095C-9036-4E7D-82E2-7B471857026D

 

As LSAs need to be refreshed in any case before max Age expires simply changing the LSA refresh timer does not provide great benefits. The LSA group pacing provides the capabitily to wait for the pacing time interval before sending new LSAs in this way there is  more efficient use of resources as multiple LSAs can be refreshed in a single LSU update packet. The default LSA group pacing timer is 240 seconds and this timer can be configured on Cisco routers. LSA group pacing also avoids a global synchronization of all locally generated LSAs that could happen in previous implementations.

 

Hope to help

Giuseppe

 

 

VIP Engager

Re: OSPF LSA Refresh Interval

Hi,

Why do you want to change the timer? What is special requirements?

 

There is two-timer in the OSPF SLAs 1. MaxAge and 2. LSRefreshTimer.

 

Every router will send a fresh copy of SLA after every 30 minutes with an incremented sequence number and age of zero.  If the router will not receive fresh SLA within MaxAge timer which is 60 minutes the router will flush the SLA automatically. The implication here is that there must be a mechanism for preventing legitimate LSAs from reaching MaxAge and being flushed. This mechanism is the link-state refresh (LSRefreshTimer) (30 Minutes).

Regards,
Deepak Kumar,
Resume duty after a long holiday
Beginner

Re: OSPF LSA Refresh Interval


@Deepak kumar wrote:

Hi,

Why do you want to change the timer? What is special requirements?

 

There is two-timer in the OSPF SLAs 1. MaxAge and 2. LSRefreshTimer.

 

Every router will send a fresh copy of SLA after every 30 minutes with an incremented sequence number and age of zero.  If the router will not receive fresh SLA within MaxAge timer which is 60 minutes the router will flush the SLA automatically. The implication here is that there must be a mechanism for preventing legitimate LSAs from reaching MaxAge and being flushed. This mechanism is the link-state refresh (LSRefreshTimer) (30 Minutes).


Hi @Deepak kumar,

I want to change because I was simulating it on my GNS3 Lab & wanted to see the next update which comes after 30mins by default. So, I had to wait for 30mins each time. It landed me on the question that whether we can change the LSA interval or not.

Everyone's tags (3)

Re: OSPF LSA Refresh Interval


@xaviar188 wrote:
Can we change the LSA Refresh interval(30mins default) in OSPF or not?
 
P.S. I have gone through a lot of literature & googled it but can't find a clear answer (some say yes & some say no) ... & im confused now. So, plz if someone can answer it simply.

LSA refresh timer / interval can be changed in some vendors while it cannot be changed in some other vendors. For example, we can change / Tune this interval in Juniper while we cannot change it in case of Cisco Equipment. Hope, it will clarify your question.


Regards,
Waqas Karim (CCIE)
Highlighted
Beginner

Re: OSPF LSA Refresh Interval


@Waqas Karim (CCIE) wrote:

@xaviar188 wrote:
Can we change the LSA Refresh interval(30mins default) in OSPF or not?
 
P.S. I have gone through a lot of literature & googled it but can't find a clear answer (some say yes & some say no) ... & im confused now. So, plz if someone can answer it simply.

LSA refresh timer / interval can be changed in some vendors while it cannot be changed in some other vendors. For example, we can change / Tune this interval in Juniper while we cannot change it in case of Cisco Equipment. Hope, it will clarify your question.


Thanks for the clear reply. So, we cannot change it on Cisco Routers. Clear now!

Everyone's tags (3)
VIP Expert

Re: OSPF LSA Refresh Interval

Why might you want adjust it? Reason I ask, if you feel the LSA refreshes are an issue, there's can be other techniques to mitigate the impact of this OSPF feature. For example, the OSPF demand circuits feature.
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