From: Przemyslaw Karwasiecki (karwas@xxxxxxxxxxx)
Date: Tue Feb 05 2002 - 19:20:28 GMT-3
Hello,
My understanding of this problem/phenomenon is as folow:
1) you are assigning encapsulation and IP address
to serial interfaces on the spoke routers
2) spoke router learn by inverse arp (enabled by default)
about IP address of a hub router and keeps this map
in nonpersistent (RAM) memory
3) you create static map from spoke to another spoke
using as L2 address DLCI from your spoke to hub router
-- acording to Bruce Caslow book, this configuration
statement disables inverse arp on this particular DLCI.
But you alredy have, in nonpersistent memory, map from
your spoke to your hub.
4) you save your config (normal, usual wr mem)
5) you reload spoke router
---6) before spoke router has opportunity to learn via inverse arp maping between IP of your hub, and DLCI to your hub, configuration statement with static map is parsed, effectivelly stoping inverse arp on this DLCI.
---
7) Final effect -- after reload your spoke cannot ping hub router.
Now, to be technically correct, it is difficult to answer your question, because there is no sentence in your original post with question mark, but if your confusion is comming from the simple fact that router is performing dynamic inverse arp even when static map is present (against Caslow p.118), I have to tell you that I am confused as well.
In my lab behaviour is exactly as in yours:
Before reload:
r2#sh fram map Serial0 (up): ip 10.10.1.1 dlci 201(0xC9,0x3090), dynamic, broadcast,, status defined, active Serial0 (up): ip 10.10.1.3 dlci 201(0xC9,0x3090), static, CISCO, status defined, active r2#reload Proceed with reload? [confirm]
19:02:16: %SYS-5-RELOAD: Reload requested
After reload: r2#sh fram map Serial0 (up): ip 10.10.1.1 dlci 201(0xC9,0x3090), dynamic, broadcast,, status defined, active Serial0 (up): ip 10.10.1.3 dlci 201(0xC9,0x3090), static, CISCO, status defined, active
r2#sh run int s0 Building configuration...
Current configuration : 120 bytes ! interface Serial0 ip address 10.10.1.2 255.255.0.0 encapsulation frame-relay frame-relay map ip 10.10.1.3 201 end
Any comments on this? Is Caslow wrong in his statement that static frame relay map disables inverse arp on this DLCI? Or this is kind of race condition and inverse arp is faster then config parser?
Thanks for your feedback,
Przemek
On Tue, 2002-01-22 at 00:41, Muhamamd Durrani wrote: > Hi All !! > > I am running hub and spoke scenario ...all are using > physical interfaces and all PVC's are up !!! > > I am using map for spoke to see each other !!! > and spokes are using inverse-Arp to resolve HUB ip > with local DLCI > > According to bruce caslow ! > If Frame relay Map is configured for a particular > protocol and particular DLCI ..Inverse ARP for that > particular DLCI is disabled automatically !!!! > > condition: > if we saved Map statement into startup config : > > Is there any specific command to save MAP statement to > startup config !!!!! > > cause i write my config into NVRAm and reload my > router my router still running Inverse Arp to resolve > HUB ip !!!! > > Any clue !!! Am I missing something !!! > > Regards, > > > >
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