Hi Rene,
So with those types of network types ( so far 5 ) , is there any preference to use one over the other for frame relay and why ?
thx
Ahmad
Hi Ahmad,
They all work so it doesnât matter too much which one you pick.
The point-to-point or point-to-multipoint network types are probably the easiest to use. You donât require a DR/BDR election so you donât have to worry about setting the correct priority.
Rene
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19 posts were merged into an existing topic: OSPF Point-to-Point Network Type over Frame-Relay
I have a customer that is designing 4 areas in a ring configuration using /30s to Area 0 /24 DR and asked if he could make the 4 area rings network point to point connections between each router. Is this a good design? I told them it should be OK as long as a DR/BDR lived in Area 0.
Thoughts
Mike C.
Hello Michael.
I refer to yout @ReneMolenaarâs previous post where he states that [quote=âReneMolenaar, post:24, topic:921â]
They all work so it doesnât matter too much which [network topology] you pick.
The point-to-point or point-to-multipoint network types are probably the easiest to use. You donât require a DR/BDR election so you donât have to worry about setting the correct priority.
[/quote]
So it really doesnât matter which network type you choose, as long as they are configured correctly.
However, keep the following issues in mind:
- If each area is composed of a point to point connection between routers, you do not require DR/BDRs at all.
- Secondly if you are creating four areas and these areas connect to each other in a ring topology, then one of these areas will not be directly connected to area 0. You will require either a virtual link (which is not advisable as a permanent solution) or you will need to revise the topology.
I hope this has been helpful!
Laz
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Hi Rene,
Why there is no Point-To-Point non-broadcast type, I mean by the Design of OSPF why there is no such type ??
Kind Regards,
Hussein Samer
Hi Hussein,
Thereâs no need to, at the other end of a point-to-point connection there is only 1 other deviceâŠ
Broadcast traffic can be used on multi-access network, like Ethernet where you want everyone to receive certain traffic.
Rene
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Hi Guys,
Why is it that for Point-to-Multipoint (Broadcast or Non-Broadcast), you used the ip ospf network point-to-multipoint command and ip ospf network point-to-multipoint non-broadcast command.
But for Point-to-Point you didnât use the âip ospf network point-to-pointâ?
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Hello Joseph
Looking over the lessons, I see that for the OSPF Point-to-Point Network Type over Frame-Relay lesson, youâll see that the configuration parameters for a serial subinterface when configuring point to point frame relay requires you to specify the type of subinterface. In this lesson, Rene is configuring the following on the Hub:
Hub(config)#interface serial 0/0.102 point-to-point
and
Hub(config)#interface serial 0/0.103 point-to-point
Notice the point-to-point keyword. When OSPF is applied to this interface, the default network type is automatically detected as point-to-point. This is specified in the OSPF command reference below:
âŠwhere it states that the default depends on the configured ânetwork typeâ. So in the configuration, the ip ospf network point-to-point command could have been implemented, but was the default, so it was not necessary.
I hope this has been helpful!
Laz
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Isnt there a error in the network diagram and the command line?
192.168.123 subnet used for DLCI 103 part in network diagram but in configuration 192.168.13 subnet used
Hub(config)#interface serial 0/0.103 point-to-point
Hub(config-subif)#ip address 192.168.13.1 255.255.255.0
Hello Anoop
Yes there seem to be some discrepancies in the diagram, the IP address, as well as in the routing table at the end of the lesson.
Iâll let Rene know to fix these.
Thanks for pointing that out!
Laz
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Hi Rene,
I have a question about what kind of ospf network to configure, it all depends on who you ask, of course. Here goes!
In my company, for p2p links over ethernet the type of OSPF network I configure is ip ospf network point-to-point, since I consider that it is not necessary to have a choice of DR/BDR, regardless of whether the protocol/connection technology is Ethernet, FR, ppp, etcâŠ
Would this be correct?
Regards.
Hello Gerard
If you have two directly connected routers over an Ethernet link and you know you wonât be adding another router to that particular network segment, then yes, it would be correct to set up the link as a point-to-point network for OSPF. The result would be that there would be no DR/BDR elections on that particular network segment.
Technically speaking, this can be achieved. The question, however, is, why would you do it? The DR/BDR election is not particularly resource-intensive, regardless of how many routes are advertised on your OSPF network. Nor is it particularly time-consuming to affect convergence time in any substantial way. Unless you have a central OSPF router with dozens or even hundreds of point-to-point Ethernet links to other OSPF routers, making such links point-to-point for OSPF will have little to no substantial benefit. By no means is it incorrect, in fact, it is theoretically more efficient.
The question however remains, is the change worth the marginal benefit? Itâs really up to you. And remember, if in the future you (or your successor) happen to add another router to that particular network segment (by adding a switch for example), you will have to remember to remove that particular command from both of the OSPF routers, which is an additional point of failure in the process.
So yes you are right, it really depends on who you ask, and how each individual evaluates the benefits and drawbacks of each choice.
I hope this has been helpful!
Laz
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hello Mr Rene, already thank you for the explanation of the course, please for what purpose we will be called to configure these different types of OSPF Networks and for each Type please give me its deployment context. I hope my question is understood. thanks in advance
Hello Charles
Take a look at this NetworkLessons note on OSPF Network Types. There you will find details about each network type, including where and how it can be used. If you have any further more specific questions, feel free to let us know!
I hope this has been helpful!
Laz
A post was merged into an existing topic: THE Updated CCIE V1.1
Hello team,
As mentioned in one of the articles that Point-to-point link on one interface of a network can be a neighbor to broadcast network type on the other side of the link.
I just wanted to know how the situation would be for all the network types?
Like broadcast with nbma, p2mp, p2mnb, p2p?
Thank you in advance!!
Sincerely,
Jugal Modi
Hello Jugal
Your question is quite interesting. The configuration youâre asking about is known as a network type mismatch, and itâs a common issue in OSPF networking, which I believe is what youâre referring to.
Hereâs a brief rundown on how different OSPF network types interact:
- Broadcast with NBMA : A broadcast network type can form an adjacency with an NBMA network. However, you need to manually specify neighbors on the NBMA side. The broadcast side will consider the NBMA side as a broadcast and will try to establish adjacency with it.
- Point-to-Multipoint with Broadcast/NBMA/P2P: Point-to-Multipoint can form an adjacency with any network type. However, on the P2MP side, you need to manually specify the neighbors.
- P2MP with P2MNB: P2MP can form an adjacency with P2MNB, but youâll need to manually specify neighbors on both sides.
- P2P with any other type: Point-to-Point can form an adjacency with any other network type. However, manual neighbor specification may be required depending on the other network type.
The above information is academic in nature! It should never be used to create an OSPF topology in a production network!!!
Itâs always best to avoid network type mismatches, as they can lead to unexpected behavior and complicate troubleshooting. Always ensure that both sides of a link are using the same network type.
I hope this has been helpful!
Laz