RE: ospf network type non-broadcast

From: Chuck Ryan (chryan) (chryan@cisco.com)
Date: Fri May 16 2008 - 09:21:43 ART


Here are my configurations, nothing fancy, all pretty basic.

****** R1 *******

interface serial1/0
ip address 10.0.0.1 255.0.0.0
encapsulation frame-relay
no fair-queue
serial restart-delay 0
no arp frame-relay
frame-relay map ip 10.0.0.3 103
frame-relay map ip 10.0.0.2 102
no frame-relay inverse-arp

router ospf 1
network 0.0.0.0 255.255.255.255 area 0

****** R2 *******

interface serial1/0
ip address 10.0.0.2 255.0.0.0
encapsulation frame-relay
no fair-queue
serial restart-delay 0
no arp frame-relay
frame-relay map ip 10.0.0.3 201
frame-relay map ip 10.0.0.1 201
no frame-relay inverse-arp

router ospf 1
network 0.0.0.0 255.255.255.255 area 0

****** R3 *******

interface serial1/0
ip address 10.0.0.3 255.0.0.0
encapsulation frame-relay
no fair-queue
serial restart-delay 0
no arp frame-relay
frame-relay map ip 10.0.0.1 301
frame-relay map ip 10.0.0.2 301
no frame-relay inverse-arp

router ospf 1
network 0.0.0.0 255.255.255.255 area 0

Thanks,

Chuck

________________________________

From: Michel Grossenbacher [mailto:pashtuk@gmail.com]
Sent: Friday, May 16, 2008 6:41 AM
To: Chuck Ryan (chryan)
Cc: Hong Chan; Cisco certification
Subject: Re: ospf network type non-broadcast

Hi Chuck
Can you provide your FR and OSPF configs for all three Routers?
best regards

Michel

On 16/05/2008, Chuck Ryan (chryan) <chryan@cisco.com> wrote:

        Hi Hong,

        I dont have any problem establishing adjacencies with or without
the
        neighbor statements configured under the ospf routing process.
That is
        what I don't understand. I thought with a network type of
non-broadcast,
        you have to manually define your neighbors on your DR in order
to
        establish adjacencies. As it turns out for me, that's not the
case. I
        can establish ospf adjacencies with the neighbor statements AND
without
        the neighbor statements.

        I'm trying to find out why this works with no neighbor
statements
        configured, and no broadcast statement at the end of my
frame-relay map
        statements.

        Thanks,

        Chuck

        ________________________________

        From: Hong Chan [mailto:howard.chan34@gmail.com]
        Sent: Friday, May 16, 2008 12:50 AM
        To: Chuck Ryan (chryan)
        Subject: Re: ospf network type non-broadcast

        Where is your DR? Is that on the r1?
        Try to add "ip ospf priority 0" on r2 & r3, add neighbor
statement on
        r1. If still not able to form neighborship, try debug to see
how's the
        hello packet talking.

        2008/5/16 Chuck Ryan (chryan) <chryan@cisco.com>:

               Hi GS,

               I have a question about the ospf network type,
non-broadcast. In
        a
               simple 3 router pod, with r1 being the hub and r2 and r3
being
        the
               spokes, I've been reading how you need to configure a
neighbor
        statement
               under r1 in order to establish ospf adjacencies with r2
and r3.

               When I lab it up and try it, it does work. What I have
also
        found out,
               is that no neighbor statement is necessary in order to
get ospf
               adjacencies up between r1 and r2, and r1 and r3. Frankly,
I
        don't see
               the difference whether I manually define neighbors or
not, the
        results
               appear to be the same.

               Can someone explain this behavior? I thought that if you
do not
        specify
               the neighbor statement, then the adjacencies will not
come up,
        but that
               doesn't appear to be the case. Also, I am not using the
        "broadcast"
               keyword on my frame-relay map statements.

               Thanks,

               Chuck



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