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food for thoughts - pointing static route to dynamic route or using dynamic route totally

SJ K
Contributor
Contributor

Hi all,

I inherited this setup with 1 router and 1 L3 switch as illustrated in the diagram below.

The 10.10.10.1 and 10.10.10.2 are routed ports.

The 192.168.1.1 is an SVI and not a routed port.

EIGRP is setup between R1 and S2 for the below networks

192.168.0.0/24

10.10.10.0/24

192.168.1.0/24

R3 is not added as part of the EIGRP setup.

Right now, in R1, I have a EIGRP route to reach 192.168.1.0 network as below

D 192.168.1.0/24   via   10.10.10.2    S0/0

In S2, I have a static route that go to 192.168.3.0/34 to exit via gateway 192.168.1.2

S 192.168.3.0/34 via 192.168.1.2

q1) Assuming if i want to setup a route in R1 to the 192.168.3.0/24 in R3 below, is there any differences between

a) static route with gateway to the SVI in S2

192.168.3.0     255.255.255.0     192.168.1.1

b) static route with gateway to R3
192.168.3.0     255.255.255.0    192.168.1.2

c) turn on EIGRP on R3 entirely

Reason for asking this question is I have more routes in R3 and I have both method a) and b) running in Live now.  I am thinking of doing c) but i am thinking of is there any differences between them a) , b) and c)

All i can think of now is in R1, the inefficiency is that I will need 2 lookup if i use the static route method

1st is to lookup how to go to 192.168.3.0, (and it must go to the 192.168.1.0 network)

2nd is to lookup how to go to 192.168.1.0 network.

q2) Is there any difference between a) and b) methods -> such that when the packet destined to 192.168.3.0/24 reaches S2 (10.10.10.2 interface),

for method A , it will have to go the SVI before going to R3 while

for method B, the packet will go to R3 directly ?

Regards,
Noob

4 Replies 4

Richard Bradfield
Frequent Contributor
Frequent Contributor

Just enable EIGRP on R3

with networks

192.168.1.0/24

and

192.168.3.0/24

let the routing protocol sort out the routes

BTW

192.168.1.0/24 on R1 EIGRP is not required, as it is not a directly connected interface.

also add the 192.168.1.0 network to the EIGRP on S2

Hi Richard,

Thanks for your reply and sorry for the late response.

I understand turning on EIGRP will solve all these dilemma, but i am specifically interested to know the difference on method a) and b) in q2.

Hope you are able to let me know your thoughts.

Regards,
Noob

Richard Bradfield
Frequent Contributor
Frequent Contributor

the static route

192.168.3.0     255.255.255.0     192.168.1.1 on S2 will not get you very far, as it is not actually pointing to the gateway for the 192.168.3.0 network

whereas

192.168.3.0     255.255.255.0    192.168.1.2 on R2 will work,

and R3 must have routes back as below

192.168.1.0     255.255.255.0     192.168.1.1

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