Saturday, April 10, 2010

CCNP Portfolio IS-IS Labs


I'm about half way through the CCNP lab portfolio book finally. I started on the first IS-IS lab presented in the book and it refreshed my memory on a lot of the IS-IS topics which I can honestly say that I forgot. The lab was focused on the basics and the end goal was to setup an IS-iS lab where the core network was running as an IS-IS level 2 network. The other goal was to implement security measures to prevent rouge outside networks/routers from trying to create an adjacency to the current IS-IS network which was pretty straight forward. I plan on completing the IS IS portion of this book within the next week or two, I'm working overtime at the NOC this upcoming week so we'll see how far will get by this time next week rolls around!

Tuesday, April 6, 2010

Finished the OSPF CCNP Portfolio Labs



All of this studying and labs (lots and lots of labs) are starting to pay off. I'm finally starting to grasp many of the CCNP routing topics without having to reference a book or look up how to configure certain commands. I went through the OSPF challenge lab and was able to knock it out in about 20 minutes which is pretty good. One thing about troubleshooting networks is that you can gain a lot of information just from looking at the running configurations and the ip routing table. Looking at the device log (show logging) helps you determine what happened and when, this is very helpful in real world environments. Next up is IS-IS and then the redistribution chapters which is gonna teach me a lot of new techniques I bet!

Saturday, April 3, 2010

OSPF Over Frame Relay


Today worked through the CCNP Portfolio lab 3-4 which has to do with OSPF over frame relay. This lab was mostly review for though. I did finally bit the bullet and learn how to setup a Cisco router as a frame-relay switch finally. I always used the frame relay icon in GNS3 for all of my frame relay studies. It was fairly straight forward, just mainly pointing the DLCI's where they need to go and configuring the serial interfaces for frame DCE connections was all that was needed really. I also went through some of the different type of OSPF NBMA topologies you can configure, such as point-to-multipoint or creating neighbor connections through the OSPF configuration.

Sunday, March 28, 2010

CCNP OSPF lab Portfolio


I finally finished up the EIGRP section and I'm now moving through some of the OSPF labs. Right now the labs are just going over basics but I have learned a few new things that I never thought about when it came to OSPF. When configuring loopbacks with IP addresses and using OSPF as your routing protocol, If their aren't any specific Router ID's (RID) set, OSPF will use the Loopback address as the RID.

For example if I configured the loopback 1 interface with the IP address 192.168.1.1 255.255.255.0, the router would use this as the RID as well. So when you run the show ip route command, it shows up as 192.168.1.1 /32 instead of the 192.168.1.1 /24 that you have actually configured on the lo1 interface. to circumvent this, you should type in the interface command ip ospf network point-to-point which tells the router to treat the loop back interface as routing destination rather than a routing ID.

Wednesday, March 24, 2010

Multicast Protocol Overview

Multicasting enables data to be sent over networks to a group of destinations in the most efficient way. The data is sent from the source as one stream; this single data stream travels through the network. Other network devices only replicate the data through the network if they have other members on their interfaces that are apart of this destination group.

Multicast groups are identified by Class D IP addresses, which are in the range from 224.0.0.0 to 239.255.255.255. Muticast uses the Internet Group Management Protocol (IGMP) and Cisco Group Management Protocol (CGMP) for determining which network devices require the multicast data stream. Protocol Independent Multicast (PIM) is used for determining the best way to route multicast traffic.

There are many differences between Multicast and Unicast packets. Unicast duplicates a packet for each reciever that it needs to send the data too (one copy for each reciver). Multicast sends one packet stream as mentioned previously, downstream routers replicate the packets only on links where receiving hosts exist. Multicast provides the following advantages over unicast:

  • Enhanced efficiency
  • Optimized Performance
  • Support for distributed applications
The disadvantage of multicast is that it uses UDP (User Datagram Protocol) as it's transport protocol. This means that packets are only sent on "best-effort" delivery and that packets aren't sent reliably. In order to cut down on unreliable packets, the multicast applications them selves may need to provide some sort of reliability mechanisms to prevent huge data lost. This could mean more processing power needed on the hosts them selves.

Shawn Moore invites you to follow my study progress at http://shawnmoorecisco.blogspot.com/. I also invite you to download my free CCNA eBook lab book at: http://www.configurethenetwork.com.

Article Source: http://EzineArticles.com/?expert=Shawn_Moore

Sunday, March 21, 2010

EIGRP Challenge Lab


I did my best to get through all of the tasks for the EIGRP Challenge Lab but I was unable to complete two tasks because I wasn't sure what they we really wanting me to do. The first was to filter a specific network from advertising out of a routers interface. The other task was to filter a network from entering a routers interface. I wasn't sure if I was just supposed summarize the network or create access-lists, route-maps, etc to deny the traffic. Besides that I managed to finish every other task successfully.

I had to change EIGRP settings such as manual summarization, change hello timers, and implement MD5 authentication which was all pretty straight forward. The weirdest task preventing EIGRP from sending multicast updates between the neighbors R1 and R2 (As shown above). I think I figured it out by entering the following command under my EIGRP AS 1

Router 1
router eigrp 1
neighbor 172.16.12.2 s0/0

Router2
router eigrp 1
neighbor 172.16.12.1 s0/0

If any one has any better suggestions on how to limit multicast addresses or if my method was completely wrong, please let me know haha!

Saturday, March 20, 2010

A Few Different CCNA Lab Simulation Options


As all of us Cisco certified and future Cisco certified professionals know, the key to passing the CCNA is knowing your hands on configuration like the back of your hand. This presents a challenge to many of us who's budget is limited from buying the latest and greatest Cisco equipment that could cost anywhere from hundreds to thousands of dollars to create a decent lab!

Fortunately many simulation programs are out there to help replicate the hardware and software needed to pass the exam. Even newer to the Cisco world and in my opinion closer to the real thing is emulation software that uses the actual IOS to simulate working on a Cisco router.

Simulation programs provide a very affordable way to create labs to possibly pass the CCNA exam with the bare minimum requirements. There are many simulation programs to choose from. In particular you would want to look for something that has many different Cisco devices to play with along with being updates with the newest IOS commands.

This is something you should note because it's not uncommon for different IOS versions to use a slightly different set of commands to accomplish the same task. Before choosing a simulation program it is also valuable to note that you won't have access to every feature available with a real router and equipment so many commands will not be available to you.

There's also the option of using emulation software such as GNS3 which allows you to completely emulate a Cisco device without the actual hardware. You can also do cool things such as connect to a real Cisco device from the emulator program to help cut down on cost if you already have a few Cisco devices but not enough to create a full CCNA lab. There are a few downsides though as well. The main downside is that as of today, you aren't able to emulate Cisco Switches due to the way Cisco switch hardware works.

However emulators such as GNS3 has a simple Ethernet switch built in that you could use or you can connect your emulated network to an outside world to connect to your Cisco switches. The other downside is that you must have access to actual IOS images in order to use any of the emulator device. This can be particular hard to acquire unless you are a vendor or a CCIE with credentials to access these images from Cisco directly. There are many choices out there but always remember that nothing beats actual equipment and hardware!

Check Out My CCNA Lab Book At: http://www.configurethenetwork.com That Features Over 15 Scenario Based Real World Labs!

Article Source: http://EzineArticles.com/?expert=Shawn_Moore