CT brushes off...(OSPF)

Well everyone, now that I'm settled in my new job I think I'm going to starting nailing this stuff down for good.

Having redesigned anything and everything layer 3 in the network, I'm ready to put the final touches on the BSCI and finally move on to something else. Frankly, I have had the idea of this test in my head so damn long that I still feel burnt out even though I've only looked at it occasionally this last 6 months.

Well anyway, since we're a Cisco shop, EIGRP is not a problem, and I've just designed our dual-ISP topology complete with AS-Path filtering, etc, so BGP is not a major concern. It's been a LONG time since I worked OSPF into the ground so I think that is where I am going to start. I started building the physical layer topology this evening and am about ready to start hitting it hard. Just like BGP, I am sure this stuff will start rushing back to me. I plan to have this sucker knocked out cold in a couple weeks.

Wish me luck everyone.

Find more posts tagged with

SAVE $250 on Your CISCO Boot Camp — Use Code "EXAM26"

Exclusively for TechExams members for Infosec Boot Camps starting before April 30, 2026

View CISCO Boot Camps

Comments

Mrock4

You got it bro. I have confidence in you..you're pretty sharp (for an old guy). If you need anything let me know. I've beat the hell out of OSPF. Likewise, I may contact you for some BGP info..

I hear ya on wanting to move on. I've been talking about the BSCI for a long, long time now..I'm ready to open a new book.

Slowhand

Sounds like fun to me, I'll be digging into CCNP-level OSPF before long, here.

jamesp1983

good luck!

cisco_trooper

Ok. So I've configured OSPF with 5 areas + area 0 and have configured, stubs, total stubs, not-so-stubs, and totally stubby not so stubs, all redistributing external networks with both type 1 and type 2 external metrics to make sure I fully understand how each operates without a hitch. Upon configuration the stuff all came rushing back to me. Piece of cake. I'm gaining momentum and I think I actually understand the LSDB better now than I ever have.

I haven't done the NBMA stuff yet because I don't have a frame-relay switch configured right now. I know dynamips has its own implementation of a frame relay switch but it is inflexible in its configuration so I usually configure my own. I'm going to try to finish that up today and start labbing the NBMA topics in OSPF.

Look out ISIS, we will soon meet again and I shall kick your @$$....

Mrock4

Awesome man. Yeah I don't think I had a true understanding of the LSDB back in the day when we'd talk and I was 'studying'..it finally clicked when I labbed it all up though. Dynamips works great for frame relay if you can set it up properly. I'm still figuring that one out, but I just read a forum the other day where there were multiple CCIE's who passed the R&S lab with 70% or more of their studying done on Dynamips..not too shabby brother.

BTW, you got a PM.

cisco_trooper

Wowsers. I hate NBMA...but that's not the focus of this discussion, well not entirely.

So I have a frame relay cloud configured. Each multipoint router can ping every other router through the cloud. Connectivity is great.

I configured ospf, which defaults to non-broadcast for multipoint links. No neighborships form as expected. Great. Fine.

I wasn't interested in non-broadcast so I configured the network type to point-to-multipoint nonbroadcast to begin my NBMA refresher course. I manually configure the neighbors and get the topology working. I then decide to tear that down and move on to nonbroadcast. I remove the neighbor statements, set the network types back to nonbroadcast. Should be simple.

This is where the **** hits the fan. Every neighbor relationship died, EXCEPT ONE....and it refused to die. I'm like, "Ok. maybe cisco snaffued or whatever..." so I clear the OSPF process on both offending devices. Neighborship dies, but THEN here it comes creeping back. W T F? non broadcast ospf types have to have neighbors manually configured. Who the HELL does this neighborship god think he is not following the rules? Did Cisco screw up? is this thing still functioning under my original configuration.......?

BLAH!!

*** iKiLLU ****

networker050184

Is this in Dynamips? I have seen Dynamips do some buggy things with neighbor relationships.

cisco_trooper

networker050184 wrote:

Is this in Dynamips? I have seen Dynamips do some buggy things with neighbor relationships.

Yes, this was in dynamips....

I was just curious if anyone had seen this behavior before.....

networker050184

I have had it happen in labs in Dynamips especially when CPU usage is high. Most of the trouble I saw was with EIGRP though.

cisco_trooper

Yeah, with high CPU usage I would expect to see missing neighbor relationships. I would never expect to have neighbor relationships you just shouldn't have.....

This is actually a server class machine too. It is running about 2% CPU with 11 active devices so resources shouldn't be an issue. Whatever, just thought it was really weird...

networker050184

When I was running EIGRP labs I would have neighbor relationships just stay up on only one side of the link. Even after shutting down the other router completely, clearing the neighbors and waiting the only way to clear would be to restart Dynamips. Dynamips is a great tool, but still not the real thing.....

cisco_trooper

yeah, so OSPF is a piece of cake so its time to nail down ISIS. Wish me luck guys, few come out alive.....

networker050184

Good luck with the ISIS!

Mrock4

IS-IS rocks...I enjoyed studying IS-IS more than anything I think. Ironically enough, I hated IS-IS with a passion before I studied it.