Re: OSPF quiz

I guess you don't see the separation between OSPF and Frame Relay.

OSPF is a versatile protocol that can cope with different topologies.
If the network between one router and his neighbour supports
broadcasting, then it can autodiscover neighbours by so doing.
Like "Hey, anybody here want to chat?"

But it also supports running on networks that have no broadcasting
ability. Frame relay being one of them. So there you have to
tell who the neighbours are.

Easy ? Well, cisco made it more complex by enabling frame relay
interfaces to behave like if they support broadcasting.

So now you have the choice: use this virtual broadcast or not ?

HTH,
-Carlos

Kaio Vilar @ 01/06/2011 10:22 -0300 dixit:
> My question is, why I use the command neighbor in OSPF Frame Relay
> networks, I believed that only the command frame-relay map XXXX
> BROADCAST.
>
> Example
>
> R1> R2
>
> R1
> int s0 / 0
> frame-relay map ipv6 fe80:: 2102 BROADCAST
>
> Why make this command? It forces the neighborhood?
> INT S0 / 0
> IPV6 ospf neighbor FE80:: 2
>
> R2
> int s0 / 0
> Frame-relay map ipv6 fe80::1 201
>
> Regards
>
> 2011/6/1, Carlos G Mendioroz <tron_at_huapi.ba.ar>:
>> I'm not sure I understand your issue.
>> If it is a non broadcast network for OSPF, OSPF will not do broadcast,
>> so the broadcast map is useless ?
>>
>> -Carlos
>>
>> Kaio Vilar @ 01/06/2011 10:00 -0300 dixit:
>>> Master,
>>>
>>> One question about OSPFv3.
>>>
>>> Why in NON-Broadcast, I need config "neighbor x.x.x.x", the command
>>> frame-relay map x.x.x.x BROADCAST not solve the problem about
>>> neighborhood?
>>>
>>> Regards,
>>> Kaio Vilar
>>>
>>> 2011/5/31, Carlos G Mendioroz <tron_at_huapi.ba.ar>:
>>>> As someone I respected put it many times, food for thought.
>>>> Great links Petr.
>>>> -Carlos
>>>>
>>>> Petr Lapukhov @ 31/05/2011 18:50 -0300 dixit:
>>>>> Carlos,
>>>>>
>>>>> It could be interesting to compare this behavior to the way other
>>>>> protocol treat 3rd party next-hops. Also, try figuring the process that
>>>>> OSPF uses when picking up an FA for NSSA prefixes. A while ago I wrote a
>>>>> few summaries on the 3rd party NHops processing in different routing
>>>>> protocols, hope it might be helpful still:
>>>>>
>>>>> http://blog.ine.com/2010/09/02/understanding-third-party-next-hop/
>>>>> http://blog.ine.com/2009/11/13/ospf-prefix-filtering-using-forwarding-address/
>>>>>
>>>>> Look into that NSSA FA selection process, it might be amusing :)
>>>>>
>>>>> Regards,
>>>>>
>>>>> --
>>>>> Petr Lapukhov, petr_at_INE.com
>>>>> CCIE #16379 (R&S/Security/SP/Voice)
>>>>> CCDE #20100007
>>>>>
>>>>> Internetwork Expert, Inc.
>>>>> http://www.INE.com
>>>>> Toll Free: 877-224-8987
>>>>> Outside US: 775-826-4344
>>>>>
>>>>> 2011/5/31 Carlos G Mendioroz <tron_at_huapi.ba.ar
>>>>> <mailto:tron_at_huapi.ba.ar>>
>>>>>
>>>>> Just wanted to share a small quiz. Try to answer w/o labbing this
>>>>> up.
>>>>>
>>>>> Topology: Central site with a firewall connected by a lan to two
>>>>> borders (B1 and B2) using HSRP for DG (FHRP). Borders run serial
>>>>> links to
>>>>> branches. OSPF single area in the WAN.
>>>>>
>>>>> B1 and B2 have a static route to an internal network X poining to
>>>>> the
>>>>> FW. B1 redidtributes X with metric 20 metric type 1. B2 does the
>>>>> same
>>>>> thing with metric 50.
>>>>>
>>>>> At a branch,, how many routes do you see, assuming same bandwidth on
>>>>> both serial links ?
>>>>>
>>>>> --
>>>>> Carlos G Mendioroz <tron_at_huapi.ba.ar <mailto:tron_at_huapi.ba.ar>>
>>>>> LW7 EQI Argentina
>>>>>
>>>>>
>>>>> Blogs and organic groups at http://www.ccie.net
>>>>>
>>>>>
>>>>> _______________________________________________________________________
>>>>> Subscription information may be found at:
>>>>> http://www.groupstudy.com/list/CCIELab.html
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>> --
>>>> Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina
>>>>
>>>>
>>>> Blogs and organic groups at http://www.ccie.net
>>>>
>>>> _______________________________________________________________________
>>>> Subscription information may be found at:
>>>> http://www.groupstudy.com/list/CCIELab.html
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>> --
>> Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina
>>

-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net