From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Mon Nov 14 2005 - 14:04:07 GMT-3
Chris is correct. Issuing the " frame-relay interface-dlci"
command on the main interface in this case does not accomplish anything,
since the VC is already assigned to that interface by default.
Multipoint NBMA interfaces require layer 3 to layer 2 resolution. In
Frame Relay this can be either dynamic through Inverse-ARP or statically
with the "frame-relay map" command. You are disabling Inverse-ARP with
the "no frame-relay inverse-arp" command, and not configuring a static
mapping. Your configuration will work temporarily depending on your
order of operations, but try bouncing the interfaces or reloading and
you will see the problem.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
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> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Chris Lewis
> Sent: Monday, November 14, 2005 9:31 AM
> To: Mitchell, TJ; Skinner, Stephen; manoj menon; Arun Arumuganainar;
> ccielab@groupstudy.com
> Subject: RE: IE Lab Exercise
>
> TJ,
>
> Many things could have happened, along the lines of dynamic mappings
being
> created before you turn off inverse arp, however if you save the
config
> and reload, the config you show below will not allow the routers to
> communicate.
>
> I have a pod and have pasted in these configs (with adjustments for
> addressing and DLCI numbers to illustrate.
>
> R1 is hub with R2 and R3 as spokes.
>
> This is my config
> R1
> interface Serial2/0
> ip address 192.168.1.1 255.255.255.0
> encapsulation frame-relay
> no fair-queue
> frame-relay map ip 192.168.1.2 122 broadcast
> frame-relay map ip 192.168.1.3 133 broadcast
> no frame-relay inverse-arp
> end
>
> R2
> interface Serial1/0
> ip address 192.168.1.2 255.255.255.252
> encapsulation frame-relay
> no fair-queue
> frame-relay interface-dlci 221
> no frame-relay inverse-arp
>
> R3
> interface Serial2/0
> ip address 192.168.1.3 255.255.255.248
> encapsulation frame-relay
> frame-relay interface-dlci 331
> no frame-relay inverse-arp
>
> If I try to ping any of the addresses from a spoke, I get
encapsulation
> failed in the debug ip packet output.
>
> Chris
>
>
> "Mitchell, TJ" <tmitchell@allianttech.com> wrote:
> I have used the command in this exact scenario before so I know it
> works.
>
> Thanks
>
> T.J. Mitchell
>
> -----Original Message-----
> From: Skinner, Stephen [mailto:Stephen.Skinner@rbs.co.uk]
> Sent: Monday, November 14, 2005 10:11 AM
> To: 'manoj menon'; 'Chris Lewis'; Mitchell, TJ; 'Arun Arumuganainar';
> 'ccielab@groupstudy.com'
> Subject: RE: IE Lab Exercise
>
> TJ , chris, manoj
> i have just seen this in the CCO about the command "frame-relay
> interface-dlci"
> This command is typically used for subinterfaces; however, it can also
> be
> used on main interfaces. Using the frame-relay interface-dlci command
on
> main interfaces will enable the use of routing protocols on interfaces
> that
> use Inverse ARP.
>
> from what i have seen here i appologise for my previous comment`s ,
>
> regards
> Stephen Skinner
>
> > -----Original Message-----
> > From: manoj menon [SMTP:manojmenon123@yahoo.com]
> > Sent: 14 November 2005 15:08
> > To: Skinner, Stephen; 'Chris Lewis'; 'Mitchell, TJ'; 'Arun
> > Arumuganainar'; 'ccielab@groupstudy.com'
> > Subject: RE: IE Lab Exercise
> >
> > *** WARNING : This message originates from the Internet ***
> >
> >
> > Mitchel, Stephen,,
> >
> > Even on the spokes, just assigning frame-rely interface-dlci will
not
> help
> > any mapping, you got to either turn on 'inverse-arp' or state
> 'frame-relay
> > map' for that dlci....unless you use it under a point-to-point
> > sub-interface - off-course, no mapping is required on a p2p
> interface.
> >
> > Regards
> > Manoj
> >
> >
> >
> > "Skinner, Stephen" wrote:
> >
> > Also i forgot to say ,
> >
> > i have been taught that using the fram-relay interface-dlci
> command
> > assign
> > all outbound frames to that DLCI , therefore you have your
> mapping ,
> >
> >
> > althought i am beginning to doubt this
> >
> > steve
> >
> >
> > Stephen Skinner
> > > -----Original Message-----
> > > From: Skinner, Stephen
> > > Sent: 14 November 2005 15:00
> > > To: 'Chris Lewis'; Mitchell, TJ; Arun Arumuganainar;
> > > ccielab@groupstudy.com
> > > Subject: RE: IE Lab Exercise
> > >
> > > chris,
> > >
> > > i have always been told as best practise ,
> > >
> > > if you want to specify a DLCI without using static mapping you
> > should use
> > > the last command ,
> > >
> > >
> > > i forgot to say that this is for a spoke and not the hub ,
> > >
> > > i am thinking on the lab , i could leave it out and as you say
> ,it
> > would
> > > work , but it would not demonstrate my knowledge of the
> subject
> > and i
> > > believe you would be marked down for that
> > >
> > > i should have also really added the point-to-multipoint line
> to
> > the int
> > > s0/0
> > >
> > > P.S
> > > i forgot to say that this is for a spoke and not the hub ,
> > >
> > > cheers
> > >
> > > Stephen Skinner
> > >
> > > -----Original Message-----
> > > From: Chris Lewis [SMTP:chrlewiscsco@yahoo.com]
> > > Sent: 14 November 2005 14:45
> > > To: Mitchell, TJ; Skinner, Stephen; Arun Arumuganainar;
> > > ccielab@groupstudy.com
> > > Subject: RE: IE Lab Exercise
> > >
> > > *** WARNING : This message originates from the Internet ***
> > >
> > >
> > > I'm sorry TJ, I'm not sure I follow:
> > >
> > > The config supplied (it did not say for which router) was as
> > > follows:
> > >
> > > int s0/0
> > > encap frame-relay
> > > no frame-relay inverse-arp
> > > ip address 1.1.1.X 255.255.255.252
> > > frame-relay interface-dlci 40X
> > >
> > > What I was trying to point out was the following:
> > >
> > > 1. All DLCIs are by default assigned to the physical
> interface, so
> > > the last command here adds nothing over and above what teh
> router
> > would do
> > > if it were not there.
> > > 2. with no fram-relay inverse-arp and no manual map
> statements,
> > > there are no L3 to L2 mappings, so no packets will be sent out
> > that
> > > interface.
> > >
> > > You seem to be thinking that turning off inverse-arp will not
> > allow
> > > the router to assign a DLCI to an interface. This is
> incorrect.
> > > inverse-arp is about mapping a layer 3 destination to a local
> > layer 2
> > > address.
> > >
> > > "Mitchell, TJ" wrote:
> > >
> > > Chris --
> > > R3 is going to use the Frame-relay map command under the
> > > physical
> > > interface.
> > > Next the configuration that was provided for the spokes (by
> > > Stephen)
> > > will work fine, since you disabled inverse arp on the spokes
> > > the DLCI's
> > > need to be specified.
> > >
> > > Using that configuration doesn't configure L3 - L2 mapping
> > > on the
> > > physical interface for the spokes.
> > >
> > > Thanks
> > >
> > > T.J. Mitchell
> > > -----Original Message-----
> > > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]
> > > On Behalf Of
> > > Chris Lewis
> > > Sent: Monday, November 14, 2005 9:10 AM
> > > To: Skinner, Stephen; 'Arun Arumuganainar';
> > > ccielab@groupstudy.com
> > > Subject: RE: IE Lab Exercise
> > >
> > > Stephen,
> > >
> > > I don't see how this would help. All DLCI's are assigned to
> > > the physical
> > > interface by default, so assigning the DLCI with that
> > > command here does
> > > nothing. Also this is a multipoint interface, so without
> > > some layer 3 to
> > > layer 2 mapping, no packets are going anywhere.
> > >
> > > Arun, I believe the IE lab solution guide gives a working
> > > config, can't
> > > you look at that? From memory I think the OSPF section gives
> > > a clue as
> > > to how spoke to spoke connectivity is achieved. On the hub
> > > you can still
> > > use map statements.
> > >
> > > Chris
> > >
> > > "Skinner, Stephen" wrote:
> > > int s0/0
> > > encap frame-relay
> > > no frame-relay inverse-arp
> > > ip address 1.1.1.X 255.255.255.252
> > > frame-relay interface-dlci 40X
> > >
> > > HTH
> > >
> > > Stephen Skinner
> > >
> > >
> > > > -----Original Message-----
> > > > From: nobody@groupstudy.com [SMTP:nobody@groupstudy.com]
> > > > Sent: 14 November 2005 11:17
> > > > To: ccielab@groupstudy.com
> > > > Subject: IE Lab Exercise
> > > >
> > > > *** WARNING : This message originates from the Internet
> > > ***
> > > >
> > > > Here are conditions .
> > > >
> > > > 1) Topology HUB and SPOKE . R3=> Hub R4 and R5 => Spoke .
> > > > 2) Use only Physical interfaces on all the 3 routers
> > > > 3) Do not use Dynamic mapping ( No Inverse ARP )
> > > > 4) Do not configure static Layer 3 to Layer 2 Mapping on
> > > spokes
> > > >
> > > > Just wondering How to configure this ?. Any body can throw
> > > some light
> > > on
> > > > it .
> > > > It would be great !!!
> > > >
> > > > Thanks and Regards
> > > > Arun
> > > >
> > > >
> > >
> > >
> >
>
This archive was generated by hypermail 2.1.4 : Thu Dec 01 2005 - 09:12:06 GMT-3