Re: [j-nsp] OSPF Confusion
On Thu, Feb 27, 2014 at 02:23:17PM -0600, Eduardo Barrios wrote: > Hi Christ, > > This from Juniper about exporting into ospf and metrics: > > http://www.juniper.net/techpubs/en_US/junos13.1/topics/concept/ospf-routing-external-metrics-overview.html > > > So if you exported your static routes into OSPF they will be a Type 2 > external metric (you can check with "show ospf database external detail"), > use only external cost and not take into account the link-state metric in > your diagram. I'm pretty sure that's not how it works. Think about the case where you have the same external route imported in multiple places. How would OSPF decide which route to take? That explanation of type-1 versus type-2 is misleading. For a type-2 route, the path to the best (lowest metric) type-2 LBA is the best path to that LBA's ASBR. So in my case, the best path from R3 to R2 (the ASBR for the external routes) is through R1 (at least that's how it looks to me). I have tried changing all of the external routes to be imported as type-1, and I get the exact same result. But being able to see all of the metrics did show some interesting things. I was playing with costs, trying to make them reflect the inverse-bandwidth model better, when I noticed that this, 11 R1 - R2 \ /20 \10 / \ / \ / \ / 10\ /50 R3 Set of metrics got me the behavior I wanted. From R3, the next hop for external routes off of R2 was R1. I was running with type-1 externals, so the path metric shows up. The metric for one of those externals is 32. So that is elucidating in one way. Now I see why, when the cost for R2->R3 equals the the cost for R3->R2, that the R3-R2 link is the best next hop. The metric is 10+1+(cost on that link) versus just (cost on that link). But in another way, I'm still confused. Why does the cost for R2->R3 come into the calculation of the cost for R3->R2 at all. I think I'm missing some basic understanding of OSPF. I'll also add that when I purposely break the R1-R3 link, the protocol does not seem to deal with it at all. So, yeah, I really seem to be lost on traffic engineering in OSPF. > * You might have to write an export policy: from protocol static + any > route-filter that you need, then accept and also add metric xx > > Thanks, > Eduardo > > Eduardo Barrios, EIT, JNCIP-SP > Telecommunications Specialist > Lower Colorado River Authority | 3505 Montopolis Dr. | Austin, TX 78744 > 512.730.6332 ph > > > > -Original Message- > From: juniper-nsp [mailto:juniper-nsp-boun...@puck.nether.net] On Behalf Of > Crist Clark > Sent: Tuesday, February 25, 2014 5:12 PM > To: Puck > Subject: [External] [j-nsp] OSPF Confusion > > . > > 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? > > . > ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] OSPF Confusion
I think Eduardo forgot to mention that you should also change the metric to be Type 1, then the internal metric will be added and I think you get the behavior you want. /Per Sent from my iPad, please ignore stupid spelling corrections! > 27 feb 2014 kl. 21:23 skrev Eduardo Barrios : > > Hi Christ, > > This from Juniper about exporting into ospf and metrics: > > http://www.juniper.net/techpubs/en_US/junos13.1/topics/concept/ospf-routing-external-metrics-overview.html > > > So if you exported your static routes into OSPF they will be a Type 2 > external metric (you can check with "show ospf database external detail"), > use only external cost and not take into account the link-state metric in > your diagram. > > * You might have to write an export policy: from protocol static + any > route-filter that you need, then accept and also add metric xx > > Thanks, > Eduardo > > Eduardo Barrios, EIT, JNCIP-SP > Telecommunications Specialist > Lower Colorado River Authority | 3505 Montopolis Dr. | Austin, TX 78744 > 512.730.6332 ph ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] OSPF Confusion
Hi Christ, This from Juniper about exporting into ospf and metrics: http://www.juniper.net/techpubs/en_US/junos13.1/topics/concept/ospf-routing-external-metrics-overview.html So if you exported your static routes into OSPF they will be a Type 2 external metric (you can check with "show ospf database external detail"), use only external cost and not take into account the link-state metric in your diagram. * You might have to write an export policy: from protocol static + any route-filter that you need, then accept and also add metric xx Thanks, Eduardo Eduardo Barrios, EIT, JNCIP-SP Telecommunications Specialist Lower Colorado River Authority | 3505 Montopolis Dr. | Austin, TX 78744 512.730.6332 ph -Original Message- From: juniper-nsp [mailto:juniper-nsp-boun...@puck.nether.net] On Behalf Of Crist Clark Sent: Tuesday, February 25, 2014 5:12 PM To: Puck Subject: [External] [j-nsp] OSPF Confusion . 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? . ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] OSPF Confusion
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 : > This may be something simple, but I've been staring at it a while and am > confused now. I have a rather simple network, > > 11 > > 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 *10.56.1.110.56.1.10x8030 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. > ___ > juniper-nsp mailing list juniper-nsp@puck.nether.net > https://puck.nether.net/mailman/listinfo/juniper-nsp > ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
[j-nsp] OSPF Confusion
This may be something simple, but I've been staring at it a while and am confused now. I have a rather simple network, 11 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 *10.56.1.110.56.1.10x8030 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. ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
