About a two weeks ago David Bombal from Configure Terminal contacted me about doing a write up for CCIE Command Memorizer. As a current CCNP student there is obviously some of the CCIE content that still goes over my head but most of the stuff I am fairly okay with. David didn’t seem to mind that I wasn’t a CCIE as yet and I sure didn’t mind giving CCIE Command Memorizer a spin so below are my thoughts and feelings.
During my initial research on the CCIE Command Memorizer I found that CCIE Command Memorizer was geared towards the CCIE Routing and Switching (R&S) Lab. When I received the application Monday two weeks ago my initial impression was that it covers without many frills and spills in an effective and efficient manner the commands in a Do-It-Yourself fill in the blanks task to objective orientated format. There is no round-about, search for things “what now” moments; everything is straight and to the point. Another bonus is that the download isn’t enormous either.
The CCIE Command Memorizer application itself is written in an e-book format, which works for the content and in that format. If like myself you like using the keyboard when you get going on command line (IOW dislike moving between the mouse+keyboard) some of the shortcuts might feel “off” and take a bit to get use to. Take heart that once you get going it all starts flowing like second nature.
My feelings on how the CCIE Command Memorizer would fit into my studies it that as a study tool / study aid as it helps you practice commands anywhere at any time as long as you have your notebook handy (face it as a CCNP I realize I am a Geeks and my notebook goes on holiday with me so this pretty much means anywhere). My current situation with a LAB is that I am busy getting racks, cabling, and other kit together to put a LAB up, the actual LAB is non-existent. In my situation the CCIE Command Memorizer is my stop-gap for actual “command” time practice as I don’t really have kit and at times no block time to zero in on a specific Technology Area and do some quick revision work with a specific focus only on that technology. This is different from the LAB where you need to setup and configure peripheral services and technologies to get to the meat close to the bone, CCIE Command Memorizer lets you focus ONLY on those parts to give you practice on those parts.
In my opinion students that would find the CCIE Command Memorizer useful would be individuals who have problems with instant recall of information when under stress or duress (people with classic test condition issues that forget as they walk through the door when in normal day-to-day they are Uber networkers) and students who need to drill things to remember (repetition, repetition, repetition) information to get it to pass from short term into long term memory (this one would be me). Most other students may also find it handy to bridge the book theory and lab practical (where you just went through the theory to quickly go over the practical again to cement the knowledge just a bit more).
From my perspective as a CCNP student the CCIE Command Memorizer shares most (if not all) of the content material with the CCNP that I cared to check up on. In the two weeks I have been working through EIGRP and OSPF (notes to follow shortly) for the BSCI. Everything I covered in theory the CCIE Command Memorizer covered + some more.
To close off for those who want a one-size-fits-all study solution don’t mistake the CCIE Command Memorizer for something it wasn’t built to be. The CCIE Command Memorizer is a STUDY TOOL / STUDY AID and not a “Complete Blended Solution” or All-In-One (aio) Product like the guys from IP Expert offer. This will mean that you will probably either attend classes from a Cisco Learning Partner and/or do labs at home or through a Rack Rental Company and/or also have Cisco Press books that will ADD TO THE VALUE the CCIE Command Memorizer.
In summation I suggest taking a serious look at the CCIE Command Memorizer and how to integrate it into your study plans. Taking all things into consideration I would seriously recommend the CCIE Command Memorizer even to current CCNP level students. The value add is easy to find and it helps to have something that you can take along as you travel that does command line study effectively without the need to spend hours on “setting up other things” before you get to play with advanced topics.
Open Shortest Path First – OSPF Fundamentals – Configuring Options On an Internal Router
To allow you to tune OSPF on an Internal Router you have the following options available at your disposal:
Defining the Router ID and Loopback interface
The Router ID (when thinking about OSPF Domains) is used to identify any given Router in the Link State Advertisements (LSAs) in an OSPF Database. A given Router on a network requires an ID (Router ID) to participate in an OSPF Domain. The Router ID can be assigned/set in one of two fashions:
In most configurations the Router ID is set by the administrator as this makes it easier to track events, internal documentation, and system-administration remotely or even on the router itself.
Setting the Router ID
The Router ID as discussed previously must be present for a Router to participate in an OSPF Domain. This Router ID can be set in one of two methods:
Setting the Router ID – Method One (Less Preferred)
The OSPF Router ID can be defined using the router-id (background link) command found in IOS.
Using the Router-ID command isn’t always the best idea when combining BGP and OSPF as both technologies employ the same method in electing a Router ID. So manually setting a Router ID (using the Router-id command) for OSPF could cause BGPs Router ID to differ from BGP which causes administration problems as well as could cause other problems at a later stage when combining the two technologies.
Should you still want to change the Router ID using this method anyway the command is:
Router(config)#router ospfRouter(config-if)#router-id ip-address
Dissecting the above when the Router ID has been chosen/assigned using the router-id command, the Router ID is kind of stable and may possibly change (barring a power cycle or a OSPF process reset). This is an important factor because changing the Router ID post (after) configuration could possibly break some OSPF configurations, such as virtual links (which as the name implies don’t exist, and could take some thinking to logically get working again).
Setting the Router ID – Method Two (Preferred)
Should the router-id command not be present/available on the router IOS you are using, and you want a more reliable method (sticky) that spans, the Router ID is automatically elected via:
I inherently look for the easier easier solution to a problem that will work long term, more work once off doesn’t matter (first off config) the solution must stick and continue working through power outages, reboots and the CEO trying his hand at “setting up” his own hardware, voice being a good example i.e. putting each end point into it’s own vlan thus ensuring QoS while the organization grows (there are limitations in the number of vlans, but I have yet to reach them).
Looking at the top the better method to control the Router ID (using automatic means) is through the use of the Loopback interface IP address. A loopback interface is a virtual interface (duh) that will always be active (cannot flap) and will be the first active interface (*shrug* logic dictates as it becomes the Router-ID, comments as I haven’t tested this out?).
The command to use a loopback is as follows (CCNA topic):
Router(config)#interface loopback inerface-numberRouter(config-if)#ip address ip-address subnet-mask
Consider assigning loopbacks a /32 mask 255.255.255.255 (1 end point) to minimize the ip space usage of the virtual interface(s) on the network (use it dont use it). I have come across some places that say that loopbacks wont work with the /32 mask (cant find source again), I will verify once I setup my kit again. In that case use the smallest (/31 or /30).
What I want to take away from this is should the Router ID be chosen/assigned using the loopback interface, the Router ID is stable and wont change. What’s important here is that a Loopback interfaces is NOT a physical interface thus cannot go up and down (flap) and therefore is not as unstable element in the network (i.e. loopback is stable) and thus is more desirable. Even in the event of a power cycle the loopback will once again be the Router ID.
Think about including the Loopback interface in the general network commands even if you aren’t configuring OSPF. This gives you an easy point to ping to should there be a need to troubleshoot (can I reach point A from point B) this should tell you alot about Layer 1 if the interface is un-shut and it has an ip-address.
Changing the COST
The COST metric on a Cisco is calculated as 100,000,000 bps divided by the bandwidth of the interface in bits per seconds. Sometimes when using a fast interface type (FE and GE) or when dealing with inter-vendor situations (Cisco / 3COM / HP) changing the default cost metric becomes a requirement (this is due to (1) faster link speeds not calculating correctly (2) or the metric equations being different between inter-vendor kit).
The command to change default cost:
Router(config-if)#ip ospf cost costThe cost variable is a 16-bit value (0 to 65,535). The lower values being the more preferred costs while higher being less preferred (shown below).
As you can see in the above table Fast Ethernet is the “drop off point” (where all things being 1) for the “fast” links (Fast Ethernet and Gigabit Ethernet both equal 1). In this case it would be better to manipulate the default cost so that the Gigabit Ethernet link is preferred over the Fast Ethernet Link. This would mean changing the cost per interface.
Another way to deal with high-bandwidth paths is to change the way a Cisco calculates cost (mess with the equation). We adjust the numerator in the automatic calculation (the Cisco automatic formula) to make some things happen in this case. To do this use the ospf auto-cost reference-bandwidth command on IOS, the default is 100 (Fast Ethernet) adjust it to 1000 (Gigabit Ethernet) and you will “fix” the equation.
Router(config-router)#ospf auto-cost reference-bandwidth reference bandwidthTwo very important NOTES (1) ospf auto-cost reference-bandwidth should be applied to all routers in an area if it is applied at all and the command (2) ip ospf cost overrides the calculated cost calculated by auto-cost reference-bandwidth
Determining the DR with the Priority Command
The hello field includes a priority field (if you can still remember) thus providing a mechanism by which designated router (DR) and backup designated Router (BDR) gets elected.
To be eligible for election, the priority must be a positive integer between 1 and 255 (if the priority is 0 (zero) the router cannot participate in the election process).
The highest priority wins (Cisco Router Default is 1) the election process.
Because the default is 1, to break all ties the Cisco Router ID is used as the deciding factor in the election process (ergo why hard coding the Router ID is a bad idea). The command to adjust priority (interface-by-interface mind you):
Router(config-if)#ip ospf priority numberNotes and Notices: This is a part of my personal BSCI notes and research to assist myself in learning and understanding the concepts and theory for the BSCI exam. I learn by making notes reading and writing things down and wish to file them where I cannot lose them. These notes are not to be seen, judged or mistaken for replacements to Cisco recognized and authorized training which I personally support and attend and suggest you undertake if you are going for the BSCI Certification.
If I added some value to your Cisco Experience with this post please add some value to my studies and leave a comment, question, suggestion, note of thanks or encouragement for me to hurry up and complete my certifications. My reasoning for wanting some interaction is that the last Recruiter said I need CCNP, Juniper and a Specialization track. The LOOOOONG Road to Cisco Indeed. Thanks Deon