Multiple default routes

[ncnaveen_arasu]

Hi

1) When we have two core routers in an enterprise connecting to two diffrent ISP's. and in LAN we will be having two diffrent VLAN subnets A and B connecting to layer 3 switch L3-1 and L3-2 switch respectively. where in clients are connected to L2 switch and gateway for client will be L3-1 and L3-2  switch .

How can we send segment A traffic from enterprise to ISP 1 and Segment B traffic  to ISP 2 by using static/default routes without dynamic routing protocols.

2)Can we use two default routes in a single router with diffrent AD as we can do in static routes.

Please clarify.

Thanks in advance

Naveen

[fb_webuser]

Naveen for the Core routers does it have physical connection to both L3 switchs , meaning that for example CoreR1 is connected to L3-1 and L3-2 (which should be ) or only single connection to L3-1.

---

Posted by WebUser Marwan Hassan from Cisco Support Community App

[ncnaveen_arasu]

Hi Web,

Core R1 is connected to L3-1 and core R2 is connected to L3-2. Both R1 and R2 core are interconnected.

[Stan Volansky]

Hi Naveen,

well using two default routes with different AD will not work...router will just install the one with the better AD and use it as the primary path. Use policy based routing as it routes based on the source IP address...

Rgrds,

Stan

Sent from Cisco Technical Support iPad App

[fb_webuser]

Naveen assuming that your terminating your vlans on L3 switch and not the router what you can do in this case run any redundancy protocol under the SVIs make L3-1 to be active for segment A and L3-2 to be active for segment B then on L3-1 create policy-based routing to match on segment A traffic and forward it out of interface connected to Core1 apply this PBR under svi segment A and on Core2 create PBR that would match on Segment B traffic and to have it forwarded to interface connected to Core2 and apply it under SVI segement B. but be aware that incase u applied that PBR to match on source ip address of segment A and that's it , segment A and B wouldnt be able to communicate so while creating ur ACL do the following deny source segment A going to segment B and then permit ip any any this would tell the L3 switch if any traffic going from segment A to B dont use PBR if any other traffic then use it. Again im not completely sure about how your network is currently configured , so if you could verify this would be able to support you more

---

Posted by WebUser Marwan Hassan from Cisco Support Community App