12-13-2023 02:57 AM - edited 12-13-2023 08:55 AM
I have two ISR 4351 routers and I'm trying to esatliblising connectivity between 2 routers with serial interface. Is it possible to connect with different subnets?
R1# serial 0/0/0
ip address 192.168.1.1/24
encapsulation ppp
R2# serial 0/0/0
ip address 192.168.2.1/24
encapsulation ppp
Solved! Go to Solution.
12-15-2023 12:56 AM
Hello
It is possible to do, You will need to ultise virtual-templates to accoplish it, try the following:
RTR1
int ser 0/0/0
ip address 192.168.1.1 255.255.255.0
enacp Fr
clock rate 64000
no keepalives
frame-relau map ip 192.168.2.1 121
frame-realy interface-dlci 121 ppp virtual-template 12
int virtual-template 12
ip address 192.168.1.1 255.255.255.0
RTR2
int ser 0/0/0
ip address 192.168.2.1 255.255.255.0
enacp Fr
no keepalives
frame-relau map ip 192.168.1.1 121
frame-realy interface-dlci 121 ppp virtual-template 21
int virtual-template 12
ip address 192.168.2.1 255.255.255.0
12-15-2023 10:11 AM
@Joseph W. Doherty @paul driver @DaviRocK!
It's working with static routes. Why? default route is not working. Anyway we got a solution finally. Thanks @paul driver @Joseph W. Doherty @DaviRocK!
R1:-
R2:-
PC-1 PC-2
12-13-2023 02:59 AM
It p2p so you can not use different subnet in each side.
MHM
12-13-2023 03:13 AM
Do you have any idea about it. Is there any feature or else i can go with any technology ? like MPLS
12-13-2023 03:17 AM
I already mention below how you can use lo as ip unnumbered and make p2p use different subnet
Can you more elaborate why you need different subnet in each side?
MHM
12-13-2023 03:00 AM - edited 12-13-2023 03:19 AM
Hello @kasulasaiganesh
No, you need same subnet between these two serial interfaces. Aslo, from one side, you need to configure a clock [edited] if HDLC configured.
https://linuxtiwary.com/2015/03/30/static-routing-configuartion-on-cisco-router-using-serial-port/
12-13-2023 03:06 AM
One case you can use different subnet but it so so limit
R1
LO0 1.1.1.1
Interface x
Ip unnumbered loopback 0
R2
LO0 2.2.2.2
Interface x
Ip unnumbered loopback 0
Here even if lo use different since it p2p you can use different subnet with unnumbered ip address
But again it so limit and have some restrictions
MHM
12-13-2023 03:24 AM
Ok i'll try this configuration and update you.
thank you
12-13-2023 03:11 AM
Hi
clock? is this command to establish link with different subnets.
12-13-2023 03:17 AM - edited 12-13-2023 03:21 AM
With PPP encapsulation, the clock rate command is not required. PPP does not rely on a specific clocking signal from the DCE side. The clocking is often negotiated dynamically, and PPP handles synchronization differently than HDLC.
So:
R1# serial 0/0/0
ip address 192.168.1.1/24
encapsulation ppp
R2# serial 0/0/0
ip address 192.168.1.2/24
encapsulation ppp
12-13-2023 06:39 AM
"With PPP encapsulation, the clock rate command is not required."
Are you sure? Reason I ask, Cisco shows an example of two routers, back-to-back serial, using PPP and clockrate. See PPP Configuration Example in https://www.learncisco.net/courses/icnd-2/wan-technologies/serial-encapsulation.html.
12-13-2023 03:19 AM
No, "clock(ing)" is needed on serial links to work. Normally provided by the DCE. If you have to routers back-to-back, one of them needs to provide it.
12-13-2023 03:57 AM
Hope these are physical kit, how are you connecting these Serial port ?
Look at the high level you interface IP address wrong - correct this and test it :
R1# serial 0/0/0
ip address 192.168.1.1/24
encapsulation ppp
R2# serial 0/0/0
ip address 192.168.1.2/24
encapsulation ppp
12-13-2023 06:50 AM
An interesting question.
@MHM Cisco World has already showed one way to do this indirectly.
Normally, explicit IPs on both ends would be within the same subnet. But I wonder whether it might work with a static route on each router with the far side interface network being reachable through the local router's serial interface.
12-13-2023 09:09 AM - edited 12-13-2023 09:33 AM
Before I have tried with default route. Yes! route was formed but there is no end to end communication.
12-13-2023 09:53 AM
What's the actual default route statement look like?
You also did the similar on R2?
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide