OSPF Frame Relay Network types

jskfan
jskfan used Ask the Experts™
on
I am looking to find examples about OSPF frame relay regarding the network types mentioned below, but could not find ones with clear explanation. other than point to point that seems easy the other ones are a bit confusing

 Non-Broadcast
 Broadcast
 Point-to-Point
 Point-to-Multipoint
 Point-to-Multipoint Non-Broadcast
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Don JohnstonInstructor
Top Expert 2015
Commented:
This can be rather involved. As in, I've had classes where we spend an hour (or more) talking about this.

Can you be more specific? What in particular are you looking for?

Another thing to keep in mind is that frame-relay is in it's twilight. Many providers are not offering it to new customers and for existing customers they're pushing hard to migrate off of it. Rumor is that it will not be in the next rev for CCNA certification.

Author

Commented:
** Ok... let s say I have configured the serial interface as a point to multipoint, then configured the ipospf priotity 255, and configure neighbors statically (spokes)
then I will go to serial interfaces of spokes and configure them with ip ospf priority 0, and configure the IP to DLCI mapping between spokes.
in this case...is this network called NBMA ? if so is it a Broadcast or Non- Broadcast NBMA?

** Broadcast is like ethernet...but we can configure Point to multipoint as broadcast as well as non-broadcast.. In which case we need to configure one type but not the other?

*** if we have on hub router and 2 spokes connected through Frame relay, before doing any configuration on our routers regarding routin protocols, is our  Network considered as NBMA ?

Thanks you
Don JohnstonInstructor
Top Expert 2015
Commented:
in this case...is this network called NBMA ?
Did you append the keyword "broadcast" to the end of your frame-relay map statement?

If you didn't, then it's an OSPF NBMA network. If you did, then it's an OSPF broadcast network.

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Author

Commented:
Sorry I should have given an example:

R1 is a HUB , R2 and R3 are the spokes (Frame Relay)
R1 has 2 sub-interfaces one of them S0/0.1is configured as Point to Multipoint ( there is no key word Broadcast or Non-Broadcast specified...which I believe s by default Non Broadcast if not specified)
another sub-interface is s0/0.2 is configured as point to point connecting R1 to R4
all 4 routers are in the same OSPF area.
R1,R2,R3 connecting serial interfaces are all multipoint.
in this case:
*** can we configure part of the interfaces as Multipoint and part as point to point , I mean are they compatible, considering the hello,dead time,etc....?
This is a simple configuration,

***we can configure neighbors statically on the HUb and and configure static IP to DLCI  mapping between the Spokes. and configure spokes priority with 0, so theat they don't become DR or BDR.
would this also be compatible with Point to Point.
***This a bit complex configuration...I wonder why this config needs to be used instead of the first one.

Thank you
Don JohnstonInstructor
Top Expert 2015
Commented:
I wonder why this config needs to be used instead of the first one.
"This config"  "First one"  What configs?

What exactly is this about? Is this some type of lab setup? Is this an actual network? What is it you're trying to accomplish?  And if there are configs, post them.

Author

Commented:
It is a Concept of OSPF in a Frame relay NBMA.
I need to know which Connection types can co-exist in the same OSPF area over Frame Relay.

I am going to paste the above statement here:

1*** can we configure part of the interfaces as Multipoint and part as point to point , I mean are they compatible, considering the hello,dead time,etc....?
This is a simple configuration,

2***we can configure neighbors statically on the HUb and and configure static IP to DLCI  mapping between the Spokes. and configure spokes priority with 0, so theat they don't become DR or BDR.
would this also be compatible with Point to Point.
   .This a bit complex configuration...I wonder why this config needs to be used instead of the first one (#1)
Instructor
Top Expert 2015
Commented:
I think that what you want to know is if you can mix sub-interface types and ospf network types and still get them to work.

The answer is a qualified yes.  Or more precisely, sometimes you can and sometimes you can't. But when you can, it always requires additional configuration (you have to tweak the timers, manually define the neighbors, etc.).

Author

Commented:
Thank you!!

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