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Re: Frame-Relay HELP with static mappings - one last question posted 09/18/2003
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Joe Martin wrote:

Ken,

Correct.  R2 will not propagate R3s ARP to R4.  By definition frame-relay is
a non-broadcast network.  So in order to have spoke-to-spoke connectivity
you would have to add a static mapping on R3; mapping the IP of R4 to the
dlci going to R2 (the hub), and vice versa.  Now because you added a static
mapping of the IP protocol on that VC (read DLCI), you will lose any dynamic
mappings for that protocol on that VC, once the router reboots.  Thus the
need to add a static mapping for the hub also.

An important reason why I mentioned earlier that p-p is the prefered method. In fact, aside from tripping you up in the lab, I can't think of a good reason to use multipoint.


When Cisco first supported frame relay there was no subinterface so you had only multipoint. Life sucked and so Cisco came up with the multipoint:)

Dave


Caslow does a pretty good job of explaining this in 'Bridges, Routers, and
Switches'

Hope that wasn't too confusing.  I know what I mean, I just have a hard time
spitting it out.

HTH,

Joe Martin
CCIE #12035

-----Original Message-----
From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx]On Behalf Of
Ken.Farrington@xxxxxxxxxxxxxxxxxxx
Sent: September 18, 2003 12:30 PM
To: ccielab@xxxxxxxxxxxxxx
Subject: RE: Frame-Relay HELP with static mappings - one last question


Last one on the subject - promise :) Im on a roll.


If I have a hub and spoke topology

R2-----------R3
|
|
|
|
R4

I turn in-arp on, on the multipoint subint on R2 and leave in-arp on on the
major interfaces on R3 and R4, i do not get a dynamic mapping for R3 on
router R4 and vice versa.

The way in which in-arp works, R2 will not propegate R3s ARP to R4.  would
this be correct?

Or do I need statics on R4 for R3 and vice-versa (or do I have a config
issue and it should work?)

Again, many thx



-----Original Message-----
From: Ken.Farrington@xxxxxxxxxxxxxxxxxxx
[mailto:Ken.Farrington@xxxxxxxxxxxxxxxxxxx]
Sent: 18 September 2003 19:05
To: ccielab@xxxxxxxxxxxxxx
Subject: RE: Frame-Relay HELP with static mappings :(


Proof of the pudding :))


GREAT :))


R2#sh frame map Serial0/0.1 (up): point-to-point dlci, dlci 104(0x68,0x1880), broadcast status defined, active




R2# 00:21:08: Serial0/0.2(o): dlci 106(0x18A1), pkt encaps 0x0300 0x8000 0x0000 0x80 6 (ARP), datagramsize 34 00:21:08: FR: Sending INARP Request on interface Serial0/0.2 dlci 106 for link 7 (IP) 00:21:08: Serial0/0.2(o): dlci 105(0x1891), pkt encaps 0x0300 0x8000 0x0000 0x80 6 (ARP), datagramsize 34 00:21:08: FR: Sending INARP Request on interface Serial0/0.2 dlci 105 for link 7 (IP) 00:21:09: broadcast dequeue 00:21:09: Serial0/0.2(o):Pkt sent on dlci 106(0x18A1), pkt encaps 0x300 0x8000 0x0 0x806 (ARP), datagramsize 34 00:21:09: broadcast dequeue 00:21:09: Serial0/0.2(o):Pkt sent on dlci 105(0x1891), pkt encaps 0x300 0x8000 0x0 0x806 (ARP), datagramsize 34 00:21:09: Serial0/0(i): dlci 106(0x18A1), pkt encaps 0x0300 0x8000 0x0000 0x806 (ARP), datagramsize 34 00:21:09: Serial0/0.2: FR ARP input 00:21:09: datagramstart = 0x1A00FCE, datagramsize = 34 00:21:09: Serial0/0(i): dlci 105(0x1891), pkt encaps 0x0300 0x8000 0x0000 0x806 (ARP), datagramsize 34 00:21:09: Serial0/0.2: FR ARP input 00:21:09: FR encap = 0x18A10300 00:21:09: 80 00 00 00 08 06 00 0F 08 00 02 04 00 09 00 00 00:21:09: 96 32 64 06 18 A1 96 32 64 02 01 02 00 00 00:21:09: 00:21:09: Serial0/0.2: frame relay INARP received 00:21:09: datagramstart = 0x1A0110E, datagramsize = 34 00:21:09: FR encap = 0x18910300 00:21:09: 80 00 00 00 08 06 00 0F 08 00 02 04 00 09 00 00 00:21:09: 96 32 64 05 18 91 96 32 64 02 01 02 00 00 00:21:09: 00:21:09: Serial0/0.2: frame relay INARP received 00:21:12: Serial0/0.1: Broadcast on DLCI 104 link 65(CDP) 00:21:12: Serial0/0.1(o): dlci 104(0x1881), pkt type 0x2000(CDP), datagramsize 2 98 00:21:12: broadcast dequeue 00:21:12: Serial0/0.1(o):Pkt sent on dlci 104(0x1881), pkt type 0x2000(CDP), dat agramsize 298 R2#



R2#
R2#sh frame map
Serial0/0.2 (up): ip 10.10.10.5 dlci 105(0x69,0x1890), dynamic,
              broadcast,, status defined, active
Serial0/0.2 (up): ip 10.10.10.6 dlci 106(0x6A,0x18A0), dynamic,
              broadcast,, status defined, active
Serial0/0.1 (up): point-to-point dlci, dlci 104(0x68,0x1880), broadcast
          status defined, active
R2#


-----Original Message----- From: Ken.Farrington@xxxxxxxxxxxxxxxxxxx [mailto:Ken.Farrington@xxxxxxxxxxxxxxxxxxx] Sent: 18 September 2003 18:51 To: ccielab@xxxxxxxxxxxxxx Subject: RE: Frame-Relay HELP with static mappings :(


Brian and Guys,


This is fantastic.  I am really finding somw awnsers to my questions thanks
to everyone.

Yes, you can run in-arp on a subinterfaces by turning on the frame
interface-dlci command and now am understanding the concepts of htis
command.

I feel, if I am to go into the lab, u must know that stuff inside out, not
just being able to put in the commands and hope it works.

BIG thx guys.  hope there is not to much more I ask about this
:))))))))))))))



-----Original Message-----
From: Brian McGahan [mailto:bmcgahan@xxxxxxxxxxxxxxxxxxxxxx]
Sent: 18 September 2003 18:34
To: Ken.Farrington@xxxxxxxxxxxxxxxxxxx; ccielab@xxxxxxxxxxxxxx
Subject: RE: Frame-Relay HELP with static mappings :(


Ken,


	The 'frame-relay interface-dlci' command isn't used for protocol
mappings, it's simply used to assign the VC to the interface.  By
default, all Frame-Relay VCs are assigned to the main interface.
Therefore, the 'frame-relay interface-dlci' command on the interface is
not used to assign the VC, but instead to apply attributes such as FRTS
or VoFR on a per PVC basis.

	On a point-to-point or multipoint interface, the command still
accomplishes the same thing, to assign the VC to the interface.  On
point-to-point interfaces, layer 2 to layer 3 protocol resolution is not
necessary, so assigning the VC is the only step.  For multipoint sub
interfaces, frame-relay inverse-arp is enabled by default.  Therefore,
if you use the frame-relay interface-dlci command on a multipoint
subinterface, you will automatically send inarp requests on the VC for
whatever protocols you are running on the interface.  If you use the
'frame-relay map' command, you are disabling inverse-arp for that
protocol for that VC.  If you use the 'no frame-relay inverse-arp', you
are disabling inverse-arp for all protocols for all VCs on that
interface.

HTH,

Brian McGahan, CCIE #8593
bmcgahan@xxxxxxxxxxxxxxxxxxxxxx

Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 708-362-1418 (Outside the US and Canada)



-----Original Message-----
From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx] On Behalf

Of


Ken.Farrington@xxxxxxxxxxxxxxxxxxx
Sent: Thursday, September 18, 2003 11:53 AM
To: ccielab@xxxxxxxxxxxxxx
Subject: RE: Frame-Relay HELP with static mappings :(

One thing to add, is that on the major interface when I use the frame-
relay
interface dlci command, it does not show up as a static entry and i

get a


dynamic entry

ie,

!
interface Serial0
ip address 10.10.10.4 255.255.255.0
encapsulation frame-relay
frame-relay interface-dlci 401
!

R4>sh frame map
Serial0 (up): ip 10.10.10.2 dlci 401(0x191,0x6410), dynamic,
             broadcast,, status defined, active


So even though you can put the command in, it does not seem to setup a static entry on the router and gets the mapping dynamically :))


Thx


-----Original Message-----
From: Farrington, Ken: IT (LDN)
Sent: 18 September 2003 17:49
To: ccielab@xxxxxxxxxxxxxx
Subject: RE: Frame-Relay HELP with static mappings :(


thx dave. it's just working out all the combinations now so I am confident for my lab.

and the combinations can be many correct?

Is there a default guide to what is correct or not from a Cisco
standpoint.
I know real life may be different :))

many thx for the quick reply.
Ken

-----Original Message-----
From: MADMAN [mailto:dmadlan@xxxxxxxxx]
Sent: 18 September 2003 17:44
To: Ken.Farrington@xxxxxxxxxxxxxxxxxxx
Cc: ccielab@xxxxxxxxxxxxxx
Subject: Re: Frame-Relay HELP with static mappings :(




Ken.Farrington@xxxxxxxxxxxxxxxxxxx wrote:



Please could you guys help me on this and confirm what I am saying

is


100%

correct?

Major Interface (multipoint by nature)
Only frame-relay map or Inverse ARP - Can enter interface-dlci but

it


will

not work.

Yes physical interface is multipoint though the interface dlci

comand


will work, more by accident than design as I think inverse arp is what
allows this misconfiguration to work.

point-to-point Sub Interface
frame-relay interface-dlci ONLY

multipoint Sub Interface
Only frame-relay map or Inverse ARP (cant use interface-dlci *see

below*)


R2(config)#int s0/0.1 multipoint
R2(config-subif)#frame map ip 10.10.10.4 104 bro
FRAME-RELAY INTERFACE-DLCI command should be used on point-to-point
interfaces
R2(config-subif)#frame-relay interface-dlci 104
R2(config-fr-dlci)#^Z
R2#

MY POINT ......

So if I have a point-to-point PVC between two routers, one is a
point-to-point sub int and the other end is a Major interface. I

HAVE TO


USE

"-frame interface-dlci" on the point-to-point sub int and

frame-relay


map
ip

on the otherside of the PVC which is a major interface.

(p-2-p sub-int)                    (major-int)
rtr2-------------------------------rtr4

Please could someone confirm this and let me know if there is any

good


documentation to clear this up.

Yes what you describe above is the correct config. Fun for the

lab,


don't do it in the real world;)

Dave

Many thx




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