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RE: Frame-Relay Inverse-Arp posted 03/03/2004
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InARP is not enabled for a DLCI assigned to a P2P subinterface as layer 3 to
layer 2 mapping is automatic for a P2P subinterface.  A P2P subinterface
will reply to an InARP request from another router but will not actively
InARP itself.

Here are a few InARP subinterface examples:

**********************************
*** 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



Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
bdennis@xxxxxxxxxxxxxxxxxxxxxx
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 775-745-6404 (Outside the US and Canada)


-----Original Message-----
From: Scott Morris [mailto:swm@xxxxxxxxxx] 
Sent: Tuesday, March 02, 2004 4:27 PM
To: 'Kenneth Wygand'; 'Brian Dennis'; 'Ahmed Mustafa';
ccielab@xxxxxxxxxxxxxx
Subject: RE: Frame-Relay Inverse-Arp

Inverse ARP is enabled by default for all DLCI's.  It's not particular to an
interface type or not.

What he's getting at is two-fold.

1.  If you have a sub-interface, you must ASSIGN a DLCI here, nothing gets
stuck their automagically.
2.  If you have a static mapping, this overrides a dynamic one when you look
at the "show frame map" output. 

Normally we look at having inverse arp off because the exam tells us to.  If
we have  a full mesh of PVC's, we'd learn about connections that we should
have via our physical interface (leftover/unassigned dlci's).

HTH,

 
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, CISSP,
JNCIS, et al.
IPExpert CCIE Program Manager
IPExpert Sr. Technical Instructor
swm@xxxxxxxxxx/smorris@xxxxxxxxxxxx
http://www.ipexpert.net


-----Original Message-----
From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx] On Behalf Of
Kenneth Wygand
Sent: Tuesday, March 02, 2004 6:59 PM
To: Brian Dennis; Ahmed Mustafa; ccielab@xxxxxxxxxxxxxx
Subject: RE: Frame-Relay Inverse-Arp

Brian,
 
If it's not too much bother (I'm sure you know them off the top of your
head), can you tell me for which (sub)interface types inverse-arp is
en/disabled?
 
Thanks!
Ken

	-----Original Message----- 
	From: nobody@xxxxxxxxxxxxxx on behalf of Brian Dennis 
	Sent: Tue 3/2/2004 5:57 PM 
	To: 'Ahmed Mustafa'; ccielab@xxxxxxxxxxxxxx 
	Cc: 
	Subject: RE: Frame-Relay Inverse-Arp
	
	

	        The rule of thumb is that the command is applied wherever
the IP
	address is assigned. 
	
	        As a side note, if using multipoint subinterfaces with only
static
	mappings then InARP does not need to be disabled.
	
	Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
	bdennis@xxxxxxxxxxxxxxxxxxxxxx
	Internetwork Expert, Inc.
	http://www.InternetworkExpert.com
<http://www.internetworkexpert.com/> 
	Toll Free: 877-224-8987
	Direct: 775-745-6404 (Outside the US and Canada)
	
	-----Original Message-----
	From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx] On Behalf
Of
	Ahmed Mustafa
	Sent: Monday, March 01, 2004 9:49 PM
	To: ccielab@xxxxxxxxxxxxxx
	Subject: Frame-Relay Inverse-Arp
	
	   Can the command "No Frame-relay Inverse-Arp" be applied on a
	sub-interface
	or has to be a physical interface.
	
	If there is a case where Hub router has a multipoint interface to
spoke 1
	and
	spoke 2, and another multipoint interface to spoke 3.  The scenerio
requires
	that dynamic frame-relay must be disabled on first multipoint
interface, and
	not on second one.
	
	
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