Google Gtalk - Finally Dead

Google Talk was one of those applications that I have been using on almost daily basis for years. Although google was keep sending notifications that they gonna stop gtalk for any further use and suggested to use Hang Out application, I think still many people out there were preferring to use old gtalk . But today they seem to kill the application finally

Anyways... Let's see how new Hangout App works. I need to install it's plugin into my chrome browser.

Also expect some interesting Technical posts in march... I know it's been a while.

HTH...
Deepak Arora
Evil CCIE

OSPF Path Selection With Default Information Originate - How You Gonna Fix It ? - Part 2

As OSPF recent design issue discussed here can possibly turn into obnoxious CCIEv5 R&S troubleshooting scenario, I got one email from another friend who also ran into interesting OSPF design issue recently around OSPF default information originate too.

Here is a quick topology of his network design:

At high level the design looks pretty simple. R1 & R2 are peering with WAN cloud using E-BGP. Between R1-R2-R3-R4-R5 we are running OSPF Area 0. To ensure R3-R4-R5 have reachability to external prefixes (Since it's always good to avoid BGP to IGP Redistribution), R1 & R2 are injecting default route into the network using "default-information originate always metric-type 1" option.

Also R1 & R2 are connected to each other over a link running OSPF.

Now let's talk about problem...which is the fun part :)

If R1's WAN connection goes down, R4 can't reach any external prefixes using default route any longer. Whereas at the same time both R3 & R5 don't lose their connectivity to same external prefixes.

Now ideally once R1 find it's WAN interface down, it should get default route from R2 and should be able to route R4's traffic in that direction.

Let me show you same behaviour using CLI :

Before R1's WAN Link goes down

After R1's WAN Link goes down 

No ICMP Packets Received Any Longer on R6

R1 is not installing default route from R2

See if you can figure out " WHY " behind this and offer different ways we can fix this design issue. Feel Free to post you solution, recommendation and findings under comments section. I'll update the post around next weekend with my findings and solutions to the design.

HTH...

Deepak Arora

Evil CCIE



Update

 In SPF Debug

How To Earn 50% Off On JNCIA-JUNOS Exam

While reading about Juniper Certifications on web, today evening I came across interesting URL where they asked to register first and then offered pre-assessment tests. 

As I am currently in middle of my JNCIA-JUNOS prep I thought to take a look on my progress by taking the pre-assessment exam. 

Although I scored far better than I thought to be in pre-assessment exam :) , But since I passed the pre-assessment test, to my surprise they gave me 50% discount voucher for the JNCIA-JUNOS exam.

Here is the URL in case you are interested to earn discount voucher as well :)

https://learningportal.juniper.net/

But in the mean while Jan 2015 First week seems to be good time to go for exam and start the new year with a small bang.

HTH....
Deepak Arora
Evil CCIE

Finally IPv6 Forum Certified Network Engineer (Gold)

http://www.ipv6forum.com/ipv6_education/Certified/home/applicantdetails.php?id=4510&url=http://www.ipv6forum.com/ipv6_education/Certified/home/certifiedlist.php?p=59&filter=6&limit=15


HTH...
Deepak Arora
Evil CCIE

OSPF Path Selection With Default Information Originate - How You Gonna Fix It ? - Part 1

I recently got a call from friend , he was stuck with an interesting OSPF Path Selection issue. Obviously the things didn't work the way he expected it to be :)

Now initially he was been given a Consulting task that involved Design & Configuration changes to meet a new network requirement.

Here is how the network initially looked like :

The customer had active-active WAN connections where these connections were also serving both WAN as well as Internet connectivity. Where as in LAN side they were using OSPF as shown in Topology above.

Now the new requirements given were:

> Brought Up New Internet Connection that will act as Primary Path to reach internet.

> In case the New Internet connection goes down, the old WAN cloud should still work as backup path to reach internet

> From R4's perspective, the path towards R2 should be primary path to reach internet (Through New Internet GW) while path through R3 should be backup path. I am not sure why this was a Hard Requirement but I guess the path from R4 to R3 was through RF link as shown below:

> Introduction of Static Routes, PBR, NAT for whatever reasons were not allowed to be used to solve this problem 

Now my friend tried to solve this problem in an interesting way. He Introduced RIPv2 as new IGP between R5-R3-R2 to ensure he doesn't have to change anything into existing IGP since there was a large IGP domain connected to this setup.

Using RIPv2 he injected default route into RIB of R2 and R3. He had to change distance of RIPv2 originated default route so that it can get priority over BGP injected default route. Than he tried Injecting Default Routes into OSPF domain towards R4 using "Default Information Originate " option. Since the control over path selection was required here, During default route injection he used Metric Type as 1 with Higher metric given while injection route at R3 as shown below:

Obviously the solution didn't work as expected and here is why:

As you can on R4 we still have two routes instead of one in Routing Table.

Can you figure out what's the problem here and how we can fix it in easiest way ?

Or You Have any other better solution to fix it while meeting the given restrictions ?

I'll post my solution to the problem after 2 weeks.

To be on same page here is the Addressing I Used in while labbing this up:

Here is relevant configuration:

 

Good Luck  !!! :)

HTH...

Deepak Arora

Evil CCIE

Update For Ref: See comments section for further information.

HTH...

Deepak Arora

Evil CCIE