[j-nsp] ospf rid lo0 stub advertisement

[Ivan Ivanov]

Hi Aaron,

Although the JNCx Sybex books are valuable study guide, they are quite old
now. I quickly checked the JUNOS version that the book is based on, and it
shows 5.x

It is not a surprise that you can achieve what you have quoted from the
book. This was changed at some point in the JUNOS evolution and the lo0.0
address is not anymore automatically advertised.

One other thing that was changed, after the books were released, is the way
the BGP routes that failed as-path loop check are treated. In the book, it
might be JNCIE rather the JNCIP, is stated that those routes are discarded
and can't be seen with any operational command. This behavior was changed,
and now they show as hidden routes.

Ivan,

On Tue, Feb 28, 2017 at 7:20 PM, Aaron <aaron1 at gvtc.com> wrote:

> I am using logical systems in my lab and trying to see the
> auto-advertisement of the lo0 interface working and it's not.  Any ideas ?
>
>
>
> ********************************************************************
>
> https://www.juniper.net/assets/us/en/local/pdf/study-
> guide/study-guide-jncip
> .pdf
>
>
>
> page 178 of 708 (page is actually labeled page 156) mentions the following.
>
>
>
> By default JUNOS software will obtain the OSPF router ID from the first
> interface that is detected with a non-Martian address. Because lo0 is
> always
> the first interface examined when rpd starts, explicit configuration of the
> RID under routing-options is rarely necessary. Simply assigning the desired
> IP address to the lo0 interface results in a stable and deterministic
> router
> ID.
>
>
>
> JUNOS software automatically advertises a stub route to the interface from
> which the RID is obtained; therefore it is not actually necessary to
> explicitly configure lo0 as an OSPF interface to meet the lo0 connectivity
> requirements of this configuration example.
>
>
>
> Manually configuring the RID under routing-options will affect connectivity
> to the lo0 address, as the router will no longer include a stub route for
> its lo0 interface. You will have to enable OSPF on the lo0 interface, as
> done in the previous example, if lo0 connectivity is required and you have
> assigned the RID manually.
>
>
>
> Omitting the lo0 interface from your OSPF configuration results in the lo0
> address being advertised as a stub network in the router LSAs (type 1 LSAs)
> that are generated and flooded into all areas to which a given router
> attaches.
>
> ********************************************************************
>
>
>
> -Aaron
>
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>



-- 
Best Regards!

Ivan Ivanov