RE: OSPF NBMA

From: Snow, Tim (timothy.snow@eds.com)
Date: Sun Oct 05 2003 - 22:26:16 GMT-3


The frame-relay map command with the Broadcast keyword doesn't "make it work
as a broadcast network" The broadcast only signals to the router to forward
broadcasts on this interface. If you had a subinterface and had a
"frame-relay interface-dlci" those "broadcasts" would be automaticall sent.

Keep in mind that multicasts fall under the "Broadcast" keyword as well so
the hellos send to 224.0.0.5 need that keyword. If you have a neighbor
statement, you may be unicast hellos and therefor don't need the broadcast
keyword.

Try it with RIP version 2 for example, with and without the neighbor
statement and see what happens.

Tim

-----Original Message-----
From: Mac [mailto:lmac0303@hotmail.com]
Sent: Sunday, October 05, 2003 9:11 PM
To: ccielab@groupstudy.com
Subject: OSPF NBMA

Hi, Group,

I just grabed some configuration from cisco website as below, but just don't
know why broadcast key-word is issued because that would make it work as a
broadcast network. Even if there is no neighbor command, the network should
work. Your clarification is greatly appreciated.

Thanks,

Mac

Configurations for NBMA (Using Neighbor Statements)
http://www.cisco.com/warp/public/104/18.html
      R4-4K

interface Loopback0
      ip address 3.3.3.3 255.255.255.255
     !
     interface Serial2
      ip address 1.1.1.2 255.255.255.0
      encapsulation frame-relay
      no keepalive
      frame-relay map ip 1.1.1.1 16 broadcast
     !
     router ospf 1
      network 1.1.1.0 0.0.0.255 area 0
     !

      R1-7010

interface Loopback0
      ip address 2.2.2.2 255.255.255.255
     !
     interface Serial1/0
      ip address 1.1.1.1 255.255.255.0
      encapsulation frame-relay
      no keepalive
      clockrate 2000000
      frame-relay map ip 1.1.1.2 16 broadcast
     !
     router ospf 1
      network 1.1.1.0 0.0.0.255 area 0
      neighbor 1.1.1.2 priority 2
     !

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