Best Design OSPF with Stub Area or Not

[Rowlands Price]

Hi Support,

I have two L3 switches connected with OSPF with backbone are 0

switch 2 as many vlans with interface vlans created for users

it's better to create a stub area zone in switch 2 ?

What is the best design

regards

Attached is the scheme

[Joseph W. Doherty]

Just curious, why all the alternating /25s?

Also, BTW, do you know you could replace the shown OSPF network statements with just two such statements?

[Rowlands Price]

Hi Joesph, /25 is because we used a vlan per switch and we didn't have more than 50 users by switch, so we choose reduce the mask from /24 to /25

[Joseph W. Doherty]

You misunderstand my question.

Why didn't you assign consecutive /25s, not just bottom half of /24.

New question, is no more than 50 users, why not use /26?

BTW, my prior employer actually ran out of private address space, although they had to work at it.  ; )

[Rowlands Price]

Hi Joseph, sorry, i misunderstand your question

you are righ, normally we must summurized all ip range

[M02@rt37]

Hello @Rowlands Price 

Stub areas are often used to reduce OSPF routing information, especially in scenarios where there are many routes and you want to optimize the routing table.

If Switch 2 has a large number of external routes or participates in a complex network, using a stub area might help reduce the size of the OSPF database and improve routing efficiency.

If the number of routes in Switch 2's routing table is a concern, using a stub area can help by limiting the flooding of external routes into the area.

On the other hand, if Switch 2 needs to have complete routing information and needs to participate in the OSPF backbone area, a stub area may not be appropriate.

[Rowlands Price]

Hi M02@rt37

Thanks for you message,

SW2 is a L3 with only vlans (about 10 vlans maxi) with SVI, no routers or others nodes behind SW2

[Joseph W. Doherty]

Stubs are used to keep other area routes from entering a non zero area.  So how many routes would otherwise enter the candidate stub area?