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Static routing table VS OSPF.

Hello

 

I´m studying for my 100.101 CCENT and was thinking... Is Static Routing Table much faster than OSPF? What would be the difference scaled to a big Network? Is it worth trying?

 

Thank you

Best regards

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Super Bronze

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Posting

Sorry for the late reply, but just read your post and I see no one else responded.

 

Generally there's a routing table maintained by the router.  How the routes are sourced into that table doesn't really matter.  I.e. whether the routes are sourced by static routes or OSPF doesn't matter to how "fast" the routing lookup is accomplished.

 

What can matter, to routing lookup performance, is how many route entries there are.  Often a route table being populated by a routing protocol will have many more routes than one being populated (exclusively) by static routes.

 

For other than very small networks, maintaining router route tables manually, using static routes, is generally impractical.

New Member

Hi,this is my first posting

Hi,

this is my first posting here, so please bear with errors I may make.

What also has to be considered is the CPU load a dynamic routing protocol like OSPF causes. An OSPF process can take up very much CPU usage mainly in the time period while the shortest path algorithm is executed.

Also only using static routes may give you a little plus for network security, because there isn't anything happening without you knowing it.

 

Besides that, Joseph Doherty of course is completly right. There should not be a difference in the time it takes for the packet / frame to traverse the router.

 

Regards,

Florian

Super Bronze

DisclaimerThe Author of this

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The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Florian is correct that a dynamic routing protocol does add to the processing load of the router.  However, that's mainly during initial or changes in topology (there's also some for keep alive type processing), normally very little CPU is expended for dynamic routing support, and packet forwarding can be prioritized over routing protocol processing (i.e. the dynamic routing protocol won't effectively slow actual forwarding, although overall capacity for doing so might be a tiny bit less).

In other words, in theory Forian is quite right, but in practice, other issues, for deciding between using a dynamic routing protocol vs. using static routing are of much more importantance.

New Member

 Hello,I agree with both

 

Hello,

I agree with both Joseph and Florian.

One more point from my side is that if we consider the administrative distance of both static and ospf,then yes we can say that static routing is much faster than ospf and other dyanamic routing protocols.However if we scale to a big network then configuring static route would be a headache and in that case use of dyanamic protocols is recommended keeping in mind the resource overhead associated with them.

Thanks

Super Bronze

DisclaimerThe Author of this

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

My understanding is, admin distance has more to due with how "trustworthy" we consider the source of the routing information than how fast routing is.  I.e. Generally we want to trust a route provided explictly (and manually) over one learned from a dynamic routing protocol.

Once a routing table has been updated, packet forwarding doesn't really care what the source of the update was.

New Member

Also static routes can be

Also static routes can be configured to be a floating static route, if you manipulate the administrative distance (AD) to be higher than any of the dynamic routing protocol-ADs, making the static routes "not as good as" the dynamically learned routes.

This enables you to configure for example a backup connection via dial-in, if your main connection is no working anymore (for example at a branch office).

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