RE: Frame map ip

From: Brian Dennis (brian@labforge.com)
Date: Sun Apr 06 2003 - 02:47:45 GMT-3


Why send two broadcast packets when you only need to send one?

What if you have 50 spokes, would you map broadcast for each spoke from
each spoke? If RIP had 70 networks to advertise, the spoke router needs
to send 3 packets to the hub. But if you have the 50 other mappings with
the broadcast keyword you would send 150 packets unnecessarily every 30
seconds.

Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
Director of CCIE Training and Development - IPexpert, Inc.
Mailto: brian@ipexpert.net
Toll Free: 866.225.8064
Outside U.S. & Canada: 312.321.6924

-----Original Message-----
From: OhioHondo [mailto:ohiohondo@columbus.rr.com]
Sent: Saturday, April 05, 2003 8:33 PM
To: Brian Dennis; 'DougAtHome'; 'ccielab'
Subject: RE: Frame map ip

It processes them and puts the best routes in the IP routing table.
Since
both of the RIP updates are from the same router, the RIP updates should
be
the same. I don't see a problem with that. As far as RIP is concerned,
it
received 2 updates from a neighboring router -- it just didn't wait the
full
period between updates.

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Brian Dennis
Sent: Saturday, April 05, 2003 9:35 PM
To: 'DougAtHome'; 'ccielab'
Subject: RE: Frame map ip

Let's same we have this config on a spoke router. One mapping to the hub
and the other to a second spoke run RIP as the routing protocol.

!
interface Serial1/0
 ip address 120.20.234.4 255.255.255.224
 encapsulation frame-relay
 frame-relay map ip 120.20.234.2 402 broadcast
 frame-relay map ip 120.20.234.3 402 broadcast
!
router rip
 network 120.0.0.0
!

When RIP has an update to send out the S1/0 interface it sends two of
them because of the two mappings with the broadcast keyword. Now when
the hub gets the two broadcast packets what does the hub do with them?

Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
Director of CCIE Training and Development - IPexpert, Inc.
Mailto: brian@ipexpert.net
Toll Free: 866.225.8064
Outside U.S. & Canada: 312.321.6924

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
DougAtHome
Sent: Saturday, April 05, 2003 3:23 PM
To: ccielab
Subject: Re: Frame map ip

This all surprizes me. Firstly, I would presume that Jeongwoo's
configuration would NOT work, and that broadcast is required for these
components. In my labs, after a reboot, the config would definitely
fail
without the broadcast - if not immediately, then definitely after
clearing
inarp.
Secondly, I have never seen samples where spoke to spoke maps eliminated
the
"broadcast" keyword. My understanding is that the broadcast first
allows
broadcast messages to be sent across the frame network. Secondly, where
necessary, the router emulates broadcast behavior by sending out
duplicate
messages out all dcli's referenced to that subinterface.
I don't know if I will have time to lab this out (my first attempt for
the
lab is now 3 weeks away), but would be interested in some
clarification/explanation. Thanks!

-----Original Message-----
From: Jeongwoo Park [mailto:jpark@wams.com]
Sent: Saturday, April 05, 2003 4:51 PM
To: 'ccielab@groupstudy.com'
Cc: 'Brian Dennis'
Subject: RE: Frame map ip

Thanks a lot for clarifying this.

Now I am converting this;
R2:Hub router
interface Serial0/0.234 multipoint
ip address 120.20.234.2 255.255.255.224
ip ospf network point-to-multipoint
frame-relay map ip 120.20.234.3 203 broadcast
frame-relay map ip 120.20.234.4 204 broadcast

To;
R2
its answer;
interface Serial0/0.234 multipoint
ip address 120.20.234.2 255.255.255.224
ip ospf network point-to-multipoint
frame-relay interface-dlci 203
frame-relay interface-dlci 204

I am not getting different result.
R2#frame map
Serial0/0.234 (up): ip 120.20.234.4 dlci 204(0xCC,0x30C0), dynamic,
broadcast,, status defined, active
R2#

I get only one map result. Shouldn't I get two of this?

R4:Spoke Router
interface Serial1/0
ip address 120.20.234.4 255.255.255.224
encapsulation frame-relay
ip ospf network point-to-multipoint
frame-relay map ip 120.20.234.2 402 broadcast
frame-relay map ip 120.20.234.3 402 broadcast

R3:Spoke Router
interface Serial1/0.234 point-to-point
ip address 120.20.234.3 255.255.255.224
ip ospf hello-interval 30
frame-relay interface-dlci 302

-----Original Message-----
From: Brian Dennis [mailto:brian@labforge.com]
Sent: Saturday, April 05, 2003 12:36 PM
To: 'Jeongwoo Park'; ccielab@groupstudy.com
Subject: RE: Frame map ip

Maybe there was a requirement to enable the router to ping itself.

As a side note the broadcast keyword isn't needed and is actually
causing
duplicate broadcast packets to be sent to "120.20.234.3". When spokes
map to
other spokes the broadcast keyword is useless because to hub will absorb
the
broadcast.

Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
Director of CCIE Training and Development - IPexpert, Inc.
Mailto: brian@ipexpert.net
Toll Free: 866.225.8064
Outside U.S. & Canada: 312.321.6924

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Jeongwoo Park
Sent: Saturday, April 05, 2003 11:48 AM
To: 'ccielab@groupstudy.com'
Subject: Frame map ip

Hi all.
I am doing ccie practice lab scinerio. I found a interesting answer
about
frame relay map.

its answer;
interface Serial0/0.234 multipoint
ip address 120.20.234.2 255.255.255.224
ip ospf network point-to-multipoint
frame-relay map ip 120.20.234.2 203 broadcast
frame-relay map ip 120.20.234.3 203 broadcast
frame-relay map ip 120.20.234.4 204 broadcast

As you can see, why would you want to have map frame to your own
interface
ip address? Can anyone of you explain this?

Thanks a lot,

JP



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