From: Schulz, Dave (DSchulz@dpsciences.com)
Date: Wed Aug 03 2005 - 19:09:41 GMT-3
Thanks, Mark. I'll check this out
-----Original Message-----
From: Mark Forest
To: 'Brian Dennis'; Schulz, Dave; 'lab '
Sent: 8/3/2005 6:05 PM
Subject: RE: frame-relay inverse arp
To supplement Brian's comment about FR INARP great information can be
found
in RFC 1293 which is obsoleted by 2390. As well if you have access to
the
Cisco Press Frame Relay book by Chin (ISBN: 1587051168) it gives a
fairly
decent explanation of the FR INARP process as well as LMI activities.
mf
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Brian Dennis
Sent: Wednesday, August 03, 2005 12:34 PM
To: Schulz, Dave; lab
Subject: RE: frame-relay inverse arp
Dave,
A router learns about it's DLCI's through LMI and not through
inverse-ARP. Inverse-ARP has nothing to do with learning DLCI's. I've
heard a couple people make the same statement you did before so I'm
assuming
that there must be some CCIE preparation material that says that. I can
tell you that it's an incorrect statement.
Inverse-ARP is disabled for DLCI 102 because there is a static mapping
for
DLCI 102.
*****************************************
*** InARP Disabled for IP on DLCI 102 ***
*****************************************
interface Serial0/0
no ip address
encapsulation frame-relay
!
interface Serial0/0.1 multipoint
ip address 10.1.1.1 255.255.255.0
frame-relay map ip 10.1.1.1 102 broadcast
Inverse-ARP is disabled because this is a point-to-point subinterface
and no
mappings are needed.
***********************************
*** InARP Disabled for DLCI 102 ***
***********************************
interface Serial0/0
no ip address
encapsulation frame-relay
!
interface Serial0/0.1 point-to-point
ip address 10.1.1.1 255.255.255.0
frame-relay interface-dlci 102
HTH,
Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
bdennis@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 775-745-6404 (Outside the US and Canada)
________________________________________
From: Schulz, Dave [mailto:DSchulz@dpsciences.com]
Sent: Wednesday, August 03, 2005 3:39 AM
To: Brian Dennis; nobody@groupstudy.com; Thomwin Chen ; Desmond Ong ;
lab
Subject: RE: frame-relay inverse arp
Brian -
It appears that the last examples have Inarp active, but I must be
missing
something. There is not a "no frame inverse" command on those two.
Also,
if you are using subinterfaces and the question wants you to not learn
any
unused DLCIs, then is it enough to use the "no frame inverse" on only
the
subinterfaces? Or, should you insure that you have it on the main
interface
also?
Dave
-----Original Message-----
From: nobody@groupstudy.com
To: Thomwin Chen; Desmond Ong; lab
Sent: 8/3/2005 12:15 AM
Subject: RE: frame-relay inverse arp
Thomwin,
You do not need to disable inverse-ARP on the physical
interfaces if
you are using only subinterfaces. This is because the "no frame-relay
inverse-arp" command is not inherited by subinterfaces.
Here are some examples of when inverse-ARP is enabled or disable
based on the configuration itself or based on the use of the "no
frame-relay
inverse-arp" command.
**********************************
*** InARP Enabled for DLCI 102 ***
**********************************
interface Serial0/0
no ip address
encapsulation frame-relay
!
interface Serial0/0.1 multipoint
ip address 10.1.1.1 255.255.255.0
frame-relay interface-dlci 102
**********************************
*** InARP Enabled for DLCI 102 ***
**********************************
interface Serial0/0
no ip address
encapsulation frame-relay
no frame-relay inverse-arp
!
interface Serial0/0.1 multipoint
ip address 10.1.1.1 255.255.255.0
frame-relay interface-dlci 102
***********************************
*** InARP Disabled for DLCI 102 ***
***********************************
interface Serial0/0
no ip address
encapsulation frame-relay
!
interface Serial0/0.1 multipoint
ip address 10.1.1.1 255.255.255.0
frame-relay interface-dlci 102
no frame-relay inverse-arp
*****************************************
*** InARP Disabled for IP on DLCI 102 ***
*****************************************
interface Serial0/0
no ip address
encapsulation frame-relay
!
interface Serial0/0.1 multipoint
ip address 10.1.1.1 255.255.255.0
frame-relay interface-dlci 102
no frame-relay inverse-arp IP 102
*****************************************
*** InARP Disabled for IP on DLCI 102 ***
*****************************************
interface Serial0/0
no ip address
encapsulation frame-relay
!
interface Serial0/0.1 multipoint
ip address 10.1.1.1 255.255.255.0
frame-relay map ip 10.1.1.1 102 broadcast
***********************************
*** InARP Disabled for DLCI 102 ***
***********************************
interface Serial0/0
no ip address
encapsulation frame-relay
!
interface Serial0/0.1 point-to-point
ip address 10.1.1.1 255.255.255.0
frame-relay interface-dlci 102
Also it's a myth (aka urban legend ;-) that the "no arp
frame-relay"
command stops the replies to inverse-ARP. It doesn't.
HTH,
Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
bdennis@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 775-745-6404 (Outside the US and Canada)
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Thomwin Chen
Sent: Tuesday, August 02, 2005 8:45 PM
To: Desmond Ong; 'lab'
Subject: Re: frame-relay inverse arp
Hi Desmond,
you can test it by using a simple command :
debug frame-relay packet and see why most workbooks suggest no
frame-relay
inverse-arp configured on physical FR interface.
probably, you will also need this to know : no arp frame-relay
Rgds,
Thomwin
Desmond Ong <desmond.gk@netstarnetworks.com> wrote:
hi there,
anyone can enlighten me on the following?
when to use "no frame-relay inverse arp" and when to specifically use
"no
frame-relay inverse arp ip " ???
Thanks!
Regards,
Des
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