From: Brian Dennis (bdennis@internetworkexpert.com)
Date: Tue Jun 05 2007 - 14:04:17 ART
Inverse ARP is used for network layer address resolution. DLCIs are learned
from the Frame Relay switch through LMI. One does not have anything to
really do with the other. You can disable inverse ARP on an interface but
you will still learn the DLCI status through LMI.
Here is an excerpt from RFC 2390 (Inverse Address Resolution Protocol):
7. Protocol Operation
Basic InARP operates essentially the same as ARP with the exception
that InARP does not broadcast requests. This is because the hardware
address of the destination station is already known.
When an interface supporting InARP becomes active, it should initiate
the InARP protocol and format InARP requests for each active PVC for
which InARP is active. To do this, a requesting station simply
formats a request by inserting its source hardware, source protocol
addresses and the known target hardware address. It then zero fills
the target protocol address field. Finally, it will encapsulate the
packet for the specific network and send it directly to the target
station.
Upon receiving an InARP request, a station may put the requester's
protocol address/hardware address mapping into its ARP cache as it
would any ARP request. Unlike other ARP requests, however, the
receiving station may assume that any InARP request it receives is
destined for it. For every InARP request, the receiving station
should format a proper response using the source addresses from the
request as the target addresses of the response. If the station is
unable or unwilling to reply, it ignores the request.
When the requesting station receives the InARP response, it may
complete the ARP table entry and use the provided address
information. Note: as with ARP, information learned via InARP may be
aged or invalidated under certain circumstances.
--Brian Dennis, CCIE4 #2210 (R&S/ISP-Dial/Security/SP) bdennis@internetworkexpert.com Internetwork Expert, Inc. http://www.InternetworkExpert.com Toll Free: 877-224-8987 Direct: 775-745-6404 (Outside the US and Canada)
On 6/5/07 6:33 AM, "Shakeer AC" <shakeerac@gmail.com> wrote:
> Hi David, > > Use the command no frame-relay inarp on the interface. > > clear the frame-relay inarp , save and reboot. > > This should clear all the unused PVC. > > Regards, > Shakeer > > > On 6/5/07, Boaz David <boazdavi@gmail.com> wrote: >> >> Dear group, >> >> I am studying the CCIE lab. I have the WB from IPexpert. >> >> I worked through several labs. Since I always delete and build new >> Frame-relay PVC on serial interface, I found a lot of unused PVC on that >> interfaces even I only config like >> >> interface s0/0.24 point-to-point >> frame-relay interfac-dlci 104 >> ... >> ... >> >> If I show frame-relay pvc, I can see PVC 104 togather with other >> previously >> configured PVCs. >> >> like this >> >> DLCI = 104, DLCI USAGE = UNUSED, PVC STATUS = ACTIVE, INTERFACE = >> Serial0/0 >> DLCI = 105, DLCI USAGE = UNUSED, PVC STATUS = INACTIVE, INTERFACE = >> Serial0/0 >> >> >> Is there any method to clear it out (say 105) as it difficult to my >> troubleshooting? >> >> Anyone can help? >> >> Boaz >> >> _______________________________________________________________________ >> Subscription information may be found at: >> http://www.groupstudy.com/list/CCIELab.html > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html
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