I have to honestly say, I am so relieved (for now) to have this smaller Topology to demonstrate how and why Front Door VRF's work, why they work and why we care about them at all when no Cisco training material mentions them. What is a Front Door VRF and why do I can if … Continue reading DMVPN – Adding Front Door VRFs to DMVPN Lab (Part 1), the lab is configured, but DMVPN stuck in “IKE”!
There will actually be no labbing of this one, as the same configurations will still apply to building tunnel interfaces, with just a few tweaks for the Routing Protocols swapped. What type of OSPF Area is used, why it is used, and additional OSPF configs Being that these Branches are going to have a single … Continue reading DMVPN – Quick review (non-labbed) of configs needed for OSPF as the Branches IGP with BGP running over the WAN!
The above Topology has already been configured with its respective IP Addressing / Routing Protocols, all Adjacencies are Up/Up, and we are ready to jump straight into NHRP (Next Hop Resolution Protocol) configuration on the Hub / NHS (Next Hop Server) which will be PHX1 Router in this Topology and then onto the DMVPN Spokes! … Continue reading DMVPN – Huge DMVPN Lab, multi-branch deployment considerations, Phase 1 to Phase 2 DMVPN clearly demonstrated, lots of configuration and verification!
To round off Redistribution series of posts for Dynamic Routing Redistribution, what better way to drive it home, than to Redistribute every Dynamic Routing Domain into every other one and see what we can break? There will be a LOT of output from this lab to demonstrate how to verify and configure / troubleshoot everything … Continue reading TSHOOT – Redistribution Part 5 – The OSPF / EIGRP / BGP / Redistribution lab!
I will wrap this up with a look at OSPF and BGP Redistribution, above is a Topology I labbed during ROUTE studies of the BGP MED concept, this is to demonstrate visually the difference of iBGP vs eBGP being the AS that BGP Routers reside in. Troubleshooting Redistribution into OSPF and OSPFv3 OSPF is very … Continue reading TSHOOT – Redistribution Part 3 – OSPF, OSPFv3, and BGP Redistribution review and troubleshooting!
While getting together some command prompt syntax from my lab, I got a jolt of nostalgia from labbing ROUTE, and decided to instead configure the lab Topology shown above as I started configuring my switches for Layer 3 routing and before I knew it I was troubleshooting OSPF and EIGRP Ajdacencies! I will try to … Continue reading TSHOOT – Redistribution Part 1 – Configuring an OSPF / EIGRP / iBGP Lab to completion, ready for Redistribution!
Being that it has been quite awhile since my ROUTE, this will contain a lot of core / foundation concepts, and tie them into troubleshooting as I go. That said, here we go! OSPFv2 (IPv4) review and troubleshooting OSPF is configured with a Process # that is locally significant only "router ospf #" and networks … Continue reading TSHOOT – OSPFv2, OPSv3, OSPF Address-Families, huge LSA / LSDB review, and troubleshooting everything OSPF!
Apologies for how terrible the Topology is, I took an existing picture and put some purple arrows leading off the ABR's, indicating that this is actually where Type 4 LSA's are created. Now ASBR's create Type 5 LSA's which of course are External / Redistributed routes which are shared throughout the entire routing domain across … Continue reading OSPF: Type 4 LSA’s, who creates them, why they create them, a relatively shorter post for once!
For those who have forgotten how LSA's work between Area's, let us refresh your memory: Type 1 and 2 LSA's live within their own Areas to create the SPF Tree ABR's extract the Network / Subnet Mask information to create a Type 3 LSA which it then floods into the other Area (Summary LSA in … Continue reading OSPF: Route filtering between Areas (Inter-Area) configured and explained!
Sticking with this Topology in case I need to lab something for demonstration, it is clear what routers are where. To begin, every router within any given Area should have an identical copy of the LSDB, and that only Type 1 and Type 2 LSA's are flooded only within the Area they originated. The Database … Continue reading OSPF: Database Exchange Process including messages, neighbor states, and all things neighbor forming related!
This will be our topology for most of Review, though I am currently leaving Area 34 and Area 15 out of the equation since we aren't really worried about those for review. You can create a process and an Area by configuring OSPF directly on an interface, rather than making the process and adding the … Continue reading OSPF: Creating OSPF from the interface, playing with Hello / Dead timers, intro to Hello-Multiplier and other good review!
Now I've spent hours and hours trying to figure GRE out, this was not included in my CCNP ROUTE material except for some DMVPN using mGRE, however I did want to know for practical purposes how to encapsulate broadcast / multicast traffic over an IPSec tunnel which in turn needs a GRE tunnel as there … Continue reading VPN: DEEP Dive into GRE Tunnel configuration over OSPF, explanation of behaviors and how to overcome them!
One thing that was lacking from Chris Bryants training that I found in the INE series is explanations between when to use OSPF Filter-list vs a Distribute-list. I have modified the network as reflected in the Topology so Area 34 will no longer be a stub, and Area 15 will only be an NSSA Area. … Continue reading OSPF: DEEP Dive – Distribute-List vs Filter-List, and reviewing Prefix-Lists as Filter-Lists use Prefixes to filter!
Since I already have the lab configured with different OSPF Area's, and we had a riveting exploration into the world of LSA's and the LS DB of each router, I wanted to hit some other topics again thoroughly before I switch up protocols for more DEEP Dives into all things CCNP ROUTE related! Without further … Continue reading OSPF: DEEP Dives into Summarization methods, Authentication, Default-Information Originate (Always)!
To note I used the same color I have previously for IPSec VPN tunnels, however that color is more just one of the few colors not reserved for protocols (as I generally use blue for OSPF, red for RIP, and orange for EIGRP), so this time green is for VRF-Lite. So I wanted to pull … Continue reading VRF-Lite: Complete configuration and explanation of behaviors, OSPF and EIGRP demonstration and how they work (or why the don’t work)