From: Nadeem Ansari (nadeem.ansari574@gmail.com)
Date: Fri Feb 27 2009 - 05:38:13 ARST
yeah you are absolutely correct, but this LSA is just for awareness of a
multiaccess network and its DR, and nothing to do with routing as it does
not carry any prefixes information
Regards
Nadeem
On Fri, Feb 27, 2009 at 3:55 AM, Miroslav Kosut <miroslav.kosut@gmail.com>wrote:
> Hello experts,
>
> this is what I realized while reading the OSPF's RFC:
>
> Let's say every OSPF router creates the "tree" from the "graph" when
> looking at the topology.
> (note difference between graphs and trees - tree CAN'T contain loops)
>
> When "node is a router" and "link is a network between routers", then:
>
> If you had only point to point links, branch in the tree can be divided to
> more only at nodes.
> If you had multiaccess network such as ethernet, branch can also be divided
> to more "at the network". So in this case a "fictitious" node can be in the
> middle of multiaccess network.
>
> .. and that's why Type 2 LSA exist - to describe this "fictitious" node,
> also called DR.
>
> Router LSAs describe it's connected networks, and
> Network LSAs describe it's connected routers.
>
> Hope it makes sense :-)
>
> Regards,
> Miro Kosut
>
>
> On Feb 26, 2009, at 7:55 PM, Nadeem Ansari wrote:
>
> That is true but what is the use of this LSA for routing of a packet ? It
>> is
>> just to provide awareness about multi access segment
>>
>> On Thu, Feb 26, 2009 at 9:33 PM, Ronnie Angello <ronnie.angello@gmail.com
>> >wrote:
>>
>> These LSAs are generated by the DR to advertise connectivity to a
>>> multiaccess network and connections to all of the routers that are
>>> connected to the multiaccess network.
>>>
>>> For example, consider routers A and B connected via a point to point
>>> Gigabit Ethernet link. Physically it's a point to point connection.
>>> Logically, you have both routers A and B connected to the DR
>>> "pseudonode." The router that's elected the DR will generate a Type 2
>>> LSA to advertise this pseudonode.
>>>
>>> On Thu, Feb 26, 2009 at 6:08 AM, Nadeem Ansari
>>> <nadeem.ansari574@gmail.com> wrote:
>>>
>>>> Hi Experts,
>>>>
>>>> I have an odd question related to OSPF Net Link States LSA-Type2, As it
>>>>
>>> has
>>>
>>>> information about DR, Network Mask used on multiaccess network and
>>>>
>>> attached
>>>
>>>> routers...
>>>>
>>>> What is the use and importance of this LSA in OSPF routine operation, As
>>>> election and information about DR and BDR are distributed via OSPF Adj
>>>> establishment
>>>> Need your suggestion
>>>>
>>>> Regards
>>>> Nadeem
>>>>
>>>>
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>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> Ronald Angello
>>> CCIE 17846
>>> CCDP, CCIP, CCNP
>>>
>>
>>
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