IS-IS PDU Types

Today I studied IS-IS Link-State Packet PDU's in more detail, specifically how it relates to both L1 and L2 links. I'm still a little confused on how pseudo-node works in broadcast networks but I have a feeling IS-IS is rarely if ever used as a routing protocol on a LAN network. It also got me to think about ES's (End-Systems) in a IS-IS Network. Since IS-IS uses an entirely different protocol than IP what host or computer even use IS-IS and CLNS instead of the IP stack? I'm going to have to do a little more digging around here but I suspect that it has something to do with the long history of IS-IS. I also went through my portable command book this evening and went through EIGRP commands and a simple lab using SSH instead of the usual console sessions. I think I'm going to go the security route so I might as well get used to encrypting passwords and locking down routers now! I hope everyone has Happy New Years, I won't be celebrating tonight due to my early shift tomorrow but I hope all my friends and family have fun and be safe tonight! 2010 is going to be a BIG year for me, I'm finally starting to see a shimmer of light at the end of the tunnel for a lot of goals I have set for myself.

Chapter 6 IS-IS Routed Protocol

Well today I spent a lot of time reading and re-reading the IS-IS pages on CLNS NSAP (Network Service Access Points) which is basically the OSI version of an IP address. Since I've been dealing mainly with IPv4 and some IPv6 it's been really hard to grasp the NSAP theory. Nothing like reading the same three pages over and over again until you sorta grasp what they're talking about. I believe that repetition is key to becoming good at anything and this seemed to work pretty well because after that I was able to read the rest of the pages pretty easily. NSAP works very similar to an IP protocol but it reminds me kinda of like NetBIOS for some reason. Tomorrow will be more IS-IS theory, this chapter doesn't have much configuration so may try and lab some other topics in the mean time to keep my CLI skills sharp.

Chapter 6 IS-IS

Today was a short study session this morning, only about an hour since it was mainly just reading about IS-IS (Intermediate System-Intermediate System). During my reading I'm learning that IS-IS are very similar to OSPF mainly because they were developed around the same time and the developers seemed to be in competition with each other the entire time! OSPF is the more popular protocol today based on being focused on IPv4 entirely to begin with. IS-IS uses a short of open ended protocol standard which leaves it very scalable for future purposes. IS-IS is also not nearly as complex to OSPF thanks to simpler mechanisms for creating routing domains and less LSP's (Link-State Packets) needed to accomplish the same goal. I'll probably do a little more research on the history of this protocol tonight along with lab out a couple of Frame-Relay topics just to keep my mind sharp with configuring routers.

Chapter 5 Configuration Lab

I'm finally doing with Chapter 5 learning about OSPF and how to tune it specifically to your needs. Next up is a totally new technology for me IS-IS (Intermediate System-to-Intermediate System) Protocol. All I know about it so far is that it's a link-state protocol and word on the street is that it's way simplier than OSPF! I'm betting so since this chapter is only about 60 pages compared to the two 70 page chapters on OSPF. I plan on doing the end of chapter multiple choic answers here shortly or tonight and messing around with som OSPF labs I'm finding on the website http://www.sadikhov.com/forum/

OSPF Authentication and Virtual Links

I polished off the rest of the CCNP theory in the Study Guide book by going through the last few pages regarding Virtual Link connections and OSPF Authentication. You would think Cisco would of made EIGRP authentication configuration similar and as easy as OSPF is. Anyways you set these two protocols up completely different which just adds to the growing list of things I'm going to need to remember for the exam. I'm about at the half way mark in a 700 page book which only took me about a month. I estimated that it would take me around 4-5 months so I'm making real good progress. I ordered the CCNP BSCI Portable Command Guide which should come in handy when I want to get quick study sessions in during the days I work. I plan on ordering the BSCI lab guide and the exam guide once I'm near complete with this book. I can't believe how much in-depth this material is, 4 books for 1 exam for a 4 exam certification. in layman's terms it's going to take me 16 books to get this certification at this rate! In actuality though, this is the hardest out of the 4 so once I knock this one out it should be all down hill from that point. I bet I'll need at least 8-10 books though all together which is a big difference than the 2 I needed for the CCNA Certification. Even the 2 books for the CCNA was a bit overkill for that exam honestly!

OSPF Stub Types

I spent this Christmas morning studying and configuring the 3 stub types, Stub Area, Totally Stubby Area, and NSSA (Not So Stubby Area). I'm not going to even ask who came up with those names but the material made since as long as you undertood how it effects the LSA type you receive in that particular area. I also ran into something I NEVER noticed so far in the past 8 months I've been learning about Cisco. If you have two directly connected serial interfaces, you CAN'T ping you're own serial IP address if the other side of the serial link is misconfigured in any way. I spent a better part of 30 minutes troubleshooting this problem and even blaming it on the GNS3 program itself until I did a little research. Even if your serial interface shows up/up, if you can't ping your serial IP it's a good chance there's a misconfiguration on either side of the point-to-point connection. MERRY CHRISTMAS!

OSPF Default Route Summarization

My lab studies today was kinda of all over the place. One of the labs I created was testing out connections to my PC's loopback and watching frames be put on the wire (with Wireshark) to my GNS3 lab. Well some how during the testing of this I lost DNS connectivity with my PC and I couldn't for the life of me figure it out. I didn't realize it was an issue with DNS until I tried connecting to google.com using it's IP address and worked but couldn't by using it's host name. After about an hour of t-shooting my own home network (including replacing a router-switch) a simpl reboot fixed all my issues. Troubleshooting 101 tip...reboot your computer first to see if this resolves your problems! Anyways after that fiasco, I finished my studying today about learning a little bit about the different stub types and configuring a multi-homed OSPF lab dealing with route summarization.