The Forwarding-Address (FA) field and how it’s processed to make a routing decision when dealing with type 5 LSA is something very interesting. In this post I will try to bring some light to this feature.
First of all, what’s the Forwarding-Address (FA) field? Well, it’s a field located in the type 5 and type 7 OSPF LSAs. In this post I will focus on LSA5, though this explanation applies also to LSA7
The value of this field is an IP address, and it’s used to inform about which IP should be used to reach the external prefix that is announced in the LSA5. We know that LSA5′s are used to introduce in the OSPF domain information originated outside of the OSPF domain, i.e. redistributed information. When an OSPF router redistributes external info into the OSPF domain, that info is injected as an LSA5 (depending on the type of area, it could be injected as LAS7).
We have been quiet for some time now. Our current schedule is leaving us with not too much free time to dedicate to the blog, but after this week, I think we are going to be able to get back into the normal post rate.
We have been working on a educational/training site this past months, and managed to finally put it in production a few days ago.
It’s called Network Faculty (https://networkfaculty.com), and is a streaming service with videos about IT. Right now is only networking (multivendor – not all in life is Cisco), but is going to grow in a little while on Security, Programming and server stuff (virtualization, linux, service, etc). As you know we (the guys behind initial draft) are focused on networking and it was natural to come up with Networking videos first. The philosophy behind the service is a “little” bit different of what other vendors are offering:
There are 3 different ways to build an InterAS VPN. But, first of all, how can it happen to have the need of an InterAS VPN? Well, this is something that usually happens when two sites from the same customer are provided by different ISPs. In this case, both ISPs need to agree on a way to interconnect their VPNs in order to provide ent-to-end connectivity to the customer. Another typical situation is when an ISP is bought by a bigger one, and in their portfolio it’s present the service of providing VPNs. In this case, although it’s the same ISP, it still has two different networks with two different ASNs. In order to provide VPN end-to-end, it needs a way to solve the InterAS VPN issues.
I said at the beginning that there are 3 different ways to provide for this connectivity, but in fact there are 4. The three firsts are the most common, and the last one is a mix. They take the name from the chapter that explains them in the RFC2547bis. These ways are:
Hello everybody, vacation is over for us and we are back to start posting technical articles again.
Right now we are busier than ever with a project that is taking a lot of time from us, but we are going to push hard to keep updating the blog with new stuff on a regular basis. If you want to read more about a specific topic, just post it on the comment section and we will do our best to cover it.
We are also going to start rolling updates for the CCIE version of the flashcards to fix application issues and a lot of typos/spell errors in the next days. This will be done first for Android, and later we will update the iPhone version.
Right now I’m having problems with Apple, because they don’t like our app, they say that the interface is not good enough, and the iPhone CCNA version of the App was rejected. We are afraid that if we upload an update to the CCIE or CCNP version, they may reject it and pull out the application completely from the store. We know that our app does not have the best/pretty interface, but I think that is good enough to get the job done (show the flashcards). We are going to be very careful with every update we push for iOS, so this may delay a little bit the upgrade process compared to Android.
If you have the app and are enjoying it, please don’t forget to rate it on the Apple/Play Store this would help us a lot in the situations like I have described before. If we have good reviews on our apps we can use it as a tool with Apple application reviewers.
I’ll like to send a special THANK YOU, to the readers that downloaded all our applications, that is a nice gesture from all of you, and a clear sign of support.
We appreciate that. Also, I would like thank all the mails sent to us, reporting errors in the apps, issues in the flash cards or simply mentioning how cool you think our app is
Lastly, we have uploaded two new apps into the Android market for CCNA and CCNP in spanish. Spanish is our native language so it was a natural move. If interested grab it here:
Guys, summer is over, is now time to get back to work
A lot of people preparing for the CCIE don’t have a clear understanding of what a CCIE bootcamp looks like and if/when should they attend one, so to help out here is another review of the INE bootcamp. Daniel had the chance of attending this bootcamp on February and his experiences are here and here. I had a chance of going to the class recently (Aug 2012).
Before talking about the specifics of the INE bootcamp, lets talk about what’s a CCIE bootcamp? Like most networking/IT classes, it’s a course design to cover a vast amount of information in a very short time-frame (most cases 5 to 10 days), this means that the more prepared we are, the more we can get out of the class.
In terms of the CCIE, this equals a solid understanding of the core topics of the blueprint, having done extensive technology and full mock labs (most vendors will recommend that before attending a live class, the student has completed most, if not all, of their workbooks). This also means that probably the best time to attend one of these classes is near the actual lab date, since probably the maximum benefit possible will be to brush up on odd topics (EEM/ZBF/PfR anyone?) and corner cases. It’s completely possible to go to a bootcamp at the beginning of the CCIE preparation, but the cost/benefit analysis probably won’t be great.
The class was held in central London at the Rydges Kensington Hotel, the location was convenient and had easy access from public transport, also there was a large selection of hotels nearby suitable for all price ranges. A typical class day started at 9:00 AM and lasted until 8/9 PM
Hello, today is the turn to release the CCNA flashcard application. This is the third release of our app, and there is still one more to come . The previous can be found here: CCNP flashcards and CCIE flashcards.
As we did wit the CCNP version, right now is only available the Android version, and the iPhone version is pending Apple for approval. I’ll let everyone know when they released to the iTunes store.
This app contains more than 530 flash cards for our fellow CCNA students, covering the full blueprint, with very detailed cards and massive answer descriptions.
The flash cards are divided in the following CCNA topics:
If you are preparing for the CCIE, you are probably doing a lot of labs.
In my case, I use the INE rack rentals, in order to make my life easier and uniform across the different Macs I use, I created a script to automatically login into the INE rack rentals and another one to log directly into the 10 different devices in the topology with different tabs using iTerm2.
The automatic telnet login expect script:
#!/usr/bin/expect -f set timeout 20 set host [lindex $argv 0] set Username "YOUR-INE-RACK-USERNAME" set Password "YOUR-INE-RACK-PASSWORD" spawn telnet $host expect "Username: " send "$Username\r" expect "Password: " send "$Password\r" interact exit