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blue phoenix
Beginner

FRAME-RELAY MULTI-POINT ON PHYSICAL INTERFACES

Hi,

Frame relay switch has a HQ that has PVC's to BR2 and BR3.  BR2 and BR3 has PVC's only to HQ and not each other.  My goal is for BR2 and BR3 to ping each other using EIGRP as the routing protocol.

I have configured ip addresses:

HQ

192.168.1.254 /24

BR2

192.168.1.1 /24

BR3

192.168.1.2 /24

eigrp are enabled on all 3 routers

router eigrp 1

  network 192.168.1.0 0.0.0.255

I only enabled frame-relay on their interfaces and used q933a for LMI and IETF for encapsulation.

I can ping the HQ from BR2 and BR3 but then again I cannot ping BR3 from BR2.  Now on documentation, it is said the no split-horizon is enabled by default on physical interfaces and so is inverse arp.  So how come I can't ping from spoke to spoke?  Does this mean I can only ping from spoke to spoke if I configure static mappings on the spokes and disabling inverse arp?

Cheers,

1 ACCEPTED SOLUTION

Accepted Solutions
bolick
Cisco Employee

In general I think you've got it although I don't believe that Inverse ARP and no split-horizon are enabled by default on physical interfaces. Most often you'll see this configuration using sub-interfaces for the DLCIs although there's nothing technically wrong with using the physical interface. Using sub-interfaces and explicitly configuring them is a good way to avoid any ambiguity. I believe show frame-relay interface will also show you the status if I remember the command correctly. It's been years (maybe decades now) since I've spent a lot of time on frame-relay though. There are a lot of good guides and examples in the Googles though for something that never dies.

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2 REPLIES 2
bolick
Cisco Employee

In general I think you've got it although I don't believe that Inverse ARP and no split-horizon are enabled by default on physical interfaces. Most often you'll see this configuration using sub-interfaces for the DLCIs although there's nothing technically wrong with using the physical interface. Using sub-interfaces and explicitly configuring them is a good way to avoid any ambiguity. I believe show frame-relay interface will also show you the status if I remember the command correctly. It's been years (maybe decades now) since I've spent a lot of time on frame-relay though. There are a lot of good guides and examples in the Googles though for something that never dies.

View solution in original post

Yes, you are right, I was able to prove it in a lab environment that split-horizon and inverse-arp are enabled by default in physical interfaces.

I was able to solve this issue by disabling inverse-arp on all routers

I configured frame-relay map ip's to the adjacent routers as if my frame-relay network is fully-meshed but in reality all traffic will first go to the HUB.

I configured no ip split-horizon eigrp [AS number] on the serial interface

Thanks,