[j-nsp] OSPF Confusion

[Wojciech Janiszewski]

Hi Crist,

>From this Router LSA you can see that 10.56.1.1 (R3) has two links:
1) id 10.56.1.1, data 10.56.1.1, Type Transit (2)
where:
    id 10.56.1.1 - Designated Router address for that link
    data 10.56.1.1 - IP address of interface of router R3 for that link
2) id 10.56.1.17, data 10.56.1.17, Type Transit (2)
where:
    id 10.56.1.17- Designated Router address for that link
    data 10.56.1.17 - IP address of interface of router R3 for that link

I assume that R3 is a DR for that links, and then the aforementioned
outputs is correct.

If you would look at the router LSA of the other routers, for the same
links you would probably see something like this:
for R1 - id 10.56.1.1, data 10.56.1.14, Type Transit (2)
for R2 - id 10.56.1.17, data 10.56.1.22, Type Transit (2)

Regarding your question, please check the Forwarding Addresses in NSSA LSAs
and how they resolve.

Regards,
Wojciech Janiszewski


2014-02-26 0:11 GMT+01:00 Crist Clark <cjc+j-nsp at pumpky.net>:

> This may be something simple, but I've been staring at it a while and am
> confused now. I have a rather simple network,
>
>     1    1
>
> R1 --------- R2
>
>  \           /20
>
>   \10       /
>
>    \       /
>
>     \     /
>
>      \   /
>
>     10\ /20
>
>       R3
>
>
> The numbers are the OSPF metrics for each interface. The R1-R2 link is 10
> Gbps. The interface metric is manually set to 1 on R1 and R2. The other two
> links are both 1 Gbps media, but the R1-R3 is limited to 500 Mbps and the
> R2-R3 to 100 Mbps by their respective carriers. (Well, not really. This is
> a lab set up meant to simulate the real network.) I've used the 10 and 20
> metrics on the interfaces as shown to tell OSPF something about that.
>
>
> What I want to happen is all traffic from R3 to go to both R1 and R2 via
> the R1-R3 link unless that link is down. With the costs configured as they
> are, I would think it would do that, but it's not working for R3.
>
>
> This is all a NSSA. R3 is distributing a default route into the area. Both
> R1 and R2 are importing static routes into the area. The routing on R1 and
> R2 works how I want. R2 sees R1 as the best next hop for the default and
> all of R1's statics. R1 sees R3 as the default next hop and sees R2 as best
> for all of R2's statics.
>
>
> The problem is that R3 sees R2 as the best next hop for all of the statics
> on R2. I don't understand why. The cost of the path from R3 to R2 is lowest
> via R1, 11 vs. 20, right?
>
>
> R3 is a EX4500/4200 chassis running 11.1R3.5. In trying to troubleshoot
> this, I'm also a bit baffled by the router LSA that R3 is sending out to
> the area. Here's the IP info for the links,
>
>
> R1-R2:  160.33.151.85-160.33.151.86/30
>
> R1-R3:  10.56.1.14-10.56.1.1/28
>
> R2-R3:  10.56.1.22-10.56.1.17/29
>
>
> But when I look at the LSA for itself in R3's database,
>
>
>     OSPF database, Area 0.0.0.1
>
>  Type       ID               Adv Rtr           Seq      Age  Opt  Cksum
>  Len
>
> Router  *10.56.1.1        10.56.1.1        0x80000030  2005  0x20 0x9786
>  48
>
>   bits 0x2, link count 2
>
>   id 10.56.1.1, data 10.56.1.1, Type Transit (2)
>
>     Topology count: 0, Default metric: 10
>
>   id 10.56.1.17, data 10.56.1.17, Type Transit (2)
>
>     Topology count: 0, Default metric: 20
>
>   Topology default (ID 0)
>
>     Type: Transit, Node ID: 10.56.1.17
>
>       Metric: 20, Bidirectional
>
>     Type: Transit, Node ID: 10.56.1.1
>
>       Metric: 10, Bidirectional
>
>   Gen timer 00:09:48
>
>   Aging timer 00:26:35
>
>   Installed 00:33:25 ago, expires in 00:26:35, sent 00:33:23 ago
>
>   Last changed 00:36:20 ago, Change count: 22, Ours
>
> It looks like its listing itself in as its neighbors? Wha'?
>
> The other devices' router LSAs look like I expect. BTW, the other two
> routers are Palo Alto Networks firewalls.
>
> Like I said, I'm probably missing something easy. Haven't done much OSPF in
> JUNOS or tried much traffic shaping before.
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