Frame Relay: dynamic map created even when arp is disabled.

[BRUNO WOLLMANN]

I am studying for the CCIE R&S lab exam after having successfully passed the written. I just completed physically setting up my lab and am now working through various study material. I am currently working through Solie's "CCIE Practical Studies volume 1" and have run into some problems with Lab 13 on page 370.

Routers scotts_house and mini_me are creating dynamic mappings to starbucks_90210 even though I have configured the serial interfaces with "no frame-relay inverse-arp" and "no arp frame-relay". I have issued "clear frame-relay inarp" but the mappings eventually return. I have rebooted the routers but the mappings eventually appear.

Here are the partial configs. r2 is scotts_house. r3 is mini_me and r4 is starbucks_90210.

r2#sh run int s0/0/0

Building configuration...

Current configuration : 212 bytes

!

interface Serial0/0/0

ip address 10.10.1.10 255.255.255.248

encapsulation frame-relay

no arp frame-relay

frame-relay map ip 10.10.1.9 201

frame-relay map ip 10.10.1.11 201

no frame-relay inverse-arp

end

r2#sh fram map

Serial0/0/0 (up): ip 10.10.1.9 dlci 201(0xC9,0x3090), static,

CISCO, status defined, active

Serial0/0/0 (up): ip 10.10.1.11 dlci 201(0xC9,0x3090), static,

CISCO, status defined, active

Serial0/0/0 (up): ip 192.168.1.6 dlci 204(0xCC,0x30C0), dynamic,

broadcast,

CISCO, status defined, active

r3#sh run int s0/0/0

Building configuration...

Current configuration : 212 bytes

!

interface Serial0/0/0

ip address 10.10.1.11 255.255.255.248

encapsulation frame-relay

no arp frame-relay

frame-relay map ip 10.10.1.9 301

frame-relay map ip 10.10.1.10 301

no frame-relay inverse-arp

end

r3#sh fram map

Serial0/0/0 (up): ip 10.10.1.9 dlci 301(0x12D,0x48D0), static,

CISCO, status defined, active

Serial0/0/0 (up): ip 10.10.1.10 dlci 301(0x12D,0x48D0), static,

CISCO, status defined, active

Serial0/0/0 (up): ip 192.168.1.6 dlci 304(0x130,0x4C00), dynamic,

broadcast,

CISCO, status defined, active

r4#sh run int s0/0/0

Building configuration...

Current configuration : 143 bytes

!

interface Serial0/0/0

ip address 192.168.1.6 255.255.255.252

encapsulation frame-relay

no fair-queue

frame-relay interface-dlci 401

end

r4#sh fram map

Serial0/0/0 (up): ip 10.10.1.10 dlci 402(0x192,0x6420), dynamic,

broadcast,

CISCO, status defined, active

Serial0/0/0 (up): ip 10.10.1.11 dlci 403(0x193,0x6430), dynamic,

broadcast,

CISCO, status defined, active

Serial0/0/0 (up): ip 192.168.1.5 dlci 401(0x191,0x6410), dynamic,

broadcast,

CISCO, status defined, active

Any help would be appreciated and all posts will be rated.

thanks

Bruno

[pkhatri]

Bruno,

I believe the problem you are seeing here is that the InvARP entries have been created before you configured the frame-relay map statements. Therefore, issue the 'clear frame-relay inarp' command to clear those entries.

The entries will no longer be created the next time you reload the router.

Hope that helps - pls do remember to rate posts that help.

Paresh

[pkhatri]

One other thing, the 'no arp frame-relay' does not impact Inverse-ARP at all so it's really redundant config.

Paresh

[BRUNO WOLLMANN]

Paresh,

I have issued 'clear frame-relay inarp' but the dynamic mappings keep returning. I have gone so far as to erase the nvram, re-configure the interfaces w/ "no frame-relay inverse-arp" and then issued a "no shut" and the dynamic mappings still appear.

I have gone to the starbucks_90210 router and entered "no frame-relay inverse-arp IP 402" and "no frame-relay inverse-arp IP 403" on the serial interface and now the dynamic mappings do not happen.

Does inverse-arp need to be disabled at both ends? I would have thought that disabling on one router would make that router not create dynamic maps.

Bruno

[pkhatri]

Bruno,

I should have mentioned that it needs to be disabled at both ends.

Even if one end has inv-arp disabled, that does not stop it listening to and responding to InvARPs received from the other end.

Remove it at both ends and you will be right.

Paresh