BGP AS_PATH Attribute

I've been working through the BGP section in the CCNP Lab Portfolio book over the past week. This morning I went over a short lab regarding the AS_PATH Attribute. It's kind of strange that the BGP labs have been the shortest labs so far, you would've thought BGP would of been a pretty big section.

As other people mentioned, this chapter has a lot of mistakes and it makes the configuration of the labs confusing. You don't know if it's you not configuring the routers right or the book giving the wrong information.

Even still I managed to get through this chapter which consisted of created a special BGP access list with the use of "regular expressions".

I configured the following regular expression access list on the ISP router:

ISP(config)#ip as-path access-list 1 deny ^100$
ISP(config)#ip as-path access-list 1 permit .*

ISP(config)#router bgp 300
ISP(config)#neighbor 172.24.1.18 filter-list 1 out

Tomorrow's BGP lab seems to be longer than the other labs so we'll see just how much material I'll have to work through. I shouldn't be able to finish a full BGP lab in 15 minutes...not yet anyways :)

DHCP Router Configuration

I spent this morning reviewing DHCP router configuration and the many options that you have as a DHCP server. From what I've seen in real networks most routers won't utilize DHCP configuration unless it's for a smaller network using a Cisco 1841 or something similar. The bigger enterprise routers are usually deployed in bigger environments where there are already dedicated DHCP server(s) in place. I did learn a command that would of helped me tremendously during my CCNA studies.

To all the people studying for the CCNA try out this command on a router and you'll get a nice surprise:

Router# show ip port-map

Yup that's right, you get a complete list of the most common TCP and UDP ports used, very handy for the CCNA exam or just for a quick reference!

IS-iS over Frame Relay

I knocked out the last of the IS IS topics in the CCNP Lab Portfolio finally. One interesting caveat about IS-IS and NBMA (Non-Broadcast Multi Access) networks is that it can only perform as point-to-point connections. Which is very different from OSPF that can use different NBMA technologies such as multi-point. Tomorrow I begin the different routing manipulation topics that's a HUGE part of the exam I hear.

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!

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!

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.

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.