Frame Relay and OSPF commands

[zillah2004]

When we use OSPF as routing protocol with Frame Relay ,we have got these commands to use :

ip ospf network point-to-multipoint

ip ospf network point-to-multipoint brodcast

ip ospf network point-to-multipoint non-broadcast

What are the difference between these commands?

[JonathanUK]

Hi

Take a look at this http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a0080094202.shtml

Basically when you setup OSPF you are given choices as to the type of network which you wish to implement. The document link I provided provides descriptions of each network type.

Hope that helps if it does rate

Thanks

Jonathan

[zillah2004]

Thanks Jonathan for the link.

I could not find in the link that you posted answer to my question.

I found this link as well, but I could not find answer to my question as well.

http://www.cisco.com/warp/public/104/22.html

Thanks

[JonathanUK]

Hi

This link will tell you everything about ospf quite heavy reading though.

http://www.apps.ietf.org/rfc/rfc2328.html

Also see below

NBMA

1 (same subnet number)

Fully meshed; manually configured adjacencies; DR/BDR elected; RFC2328-defined

Point-to-Multipoint

1 (same subnet number)

Partial mesh or star; automatic adjacency; no DR/BDR elected; RFC2328-defined

Point-to-Multipoint non-broadcast

1 (same subnet number)

Partial mesh or star; manually configured adjacencies; no DR/BDR elected; RFC2328-defined

Broadcast

1 (same subnet number)

Fully meshed; automatic adjacency; DR/BDR are elected; Cisco-defined

Point-to-Point

Separate subnet for each subinterface

Partial mesh or star; subinterfaces; automatic adjacency; no DR/BDR elected; Cisco-defined

[zillah2004]

Another thing,,,Cisco says:

" The broadcast keyword provides two functions:

A- It forwards broadcast when multicasting in not enabled.

B- It smiplifies the configuration of OSPF for nonbroadcast networks that use Frame Relay ".

Why do we need to use keyword broadcast with this command below:

RTX(config-if)#frame-relay map ip 10.1.1.2 111 brodcast.

This command is static mapping between layers 3 address and layer 2 address,,,,why do we need to use broadcast keyword ?

My understanding in the static mapping we are not going to rely on broadcast to be advertised our interesting to do mapping!!!.

[JonathanUK]

Hi hope below helps the broadcast word is optional.

Similarly, the frame-relay map protocol protocol-address dlci [broadcast] command can be used to specifically assign DLCIs to the multipoint subinterfaces. The optional broadcast keyword in the frame-relay map command is required if broadcast and multicast traffic are to be sent over the specified dlci. Without the broadcast option, dynamic routing protocols such as EIGRP, OSPF and RIPv2 would not be able to advertise multicast route updates over the specified dlci. In comparison with the frame-relay interface-dlci command, the frame-relay map command performs static addressing mapping and it disables Inverse ARP on the specified dlci. In addition, the frame-relay map command is supported on the physical interface and the frame-relay map command should be used when the far end Frame Relay device does not support Inverse ARP.

Full link to article is here http://www.ciscopress.com/articles/article.asp?p=170741&seqNum=6&rl=1

Hope that helps if it does rate.

Thanks

Jonathan