Do you like this site? Remember to share it to all your friends on Facebook and Twitter!

Saturday, December 20, 2008

IOS OSPF Multi-VRF support: remember to add "capability vrf-lite" statement

IOS "Multi-VRF" to me is a solution to one of my headache. Since I failed to persuade my colleagues buying new switches, I have to make one hardware acting as two.

(The following story is really demonstrating a bad habit. You should avoid the same mistakes by prepare well before you do anything!)

Without study further at the beginning, I jumped right into configuring and enabling the Multi-VRF feature. I decided to use OSPF, so my first configuration looked like this:

router ospf 1 vrf XXXXX
 area authentication message-digest
 network area

Looks not too wrong, isn't it?

In fact, I immediately saw a lot of routing entries coming in. That's why I thought I was right at the first moment.

Then something strange came out. I checked more carefully about the routing table entries and found some routes are just missing. All OSPF externals and "intra-area"s are there, but not those "inter-area"s.

I googled a while and found this page on The missing statement is "capability vrf-lite". So the correct configuration should be like this:

router ospf 1 vrf XXXXX
 capability vrf-lite
 area authentication message-digest
 network area

A good lessen for myself!

Saturday, December 13, 2008

Subscription button is OK now!

Shining to the sky (DSC_0526)
Shining to the sky (DSC_0526),
originally uploaded by Li-Ji.
Just to let you know, the subscription inconveniences is gone now. I have completed the Feedburner account transition and all were tested OK!

Please keep subscribing!

Cisco Reading List

Thanks to Johnson Liu's blog, I found more useful web sites and blogs that help to study about Cisco. I decide to publish all my collected Cisco reading and subscription list here in OPML(?) format.

I hope it helps your study!

Subscribe when you can, bookmark otherwise!

Wednesday, December 10, 2008

Subscription button might not work sometimes because of moving Feedburner account

Yellow Daisy (DSC_0034)
Yellow Daisy (DSC_0034),
originally uploaded by Li-Ji.
I am sorry to let you know, the "Subscribe" buttons might not work sometimes for a while.

I am moving my Feedburner account into Google account. The subscription link will be changed from* to*.

I suggest you to bookmark this site and subscribe later.  Sorry for any inconveniences!

Tuesday, December 9, 2008

Manual routes only configuration practice (CNA-02-001)

CCNA Exploration 4.0, Semester 2, "Manual routes only configuration" Packet Tracer 5.0 practice file (CNA-02-001).

In this example, we practice adding "manual routes" only, to maintain full connectivity.

The diagram shown in this example is quite simple. However, we will quickly learn in it: if we maintain all the necessary routes manually by hand, we could make a lot of careless mistakes. And the result is only a partially working network. The worst thing is, we have to examine all routers to find out where the problem is!

That's why we have to study so much about "automatic" ways to maintain full connectivity!

Many documents did not explain the following terms clear. In fact:

  • Static means Manual
  • Dynamic means Automatic
We used to choose "Static" and "Dynamic" to call entries in routing table and also those in MAC address table. I suggest "Manual" and "Automatic" would be better and clearer substitutions!

Popular Posts