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
 router-id 1.2.3.4
 area 1.2.3.0 authentication message-digest
 network 1.2.3.0 0.0.0.255 area 1.2.3.0

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 Cisco.com. The missing statement is "capability vrf-lite". So the correct configuration should be like this:

router ospf 1 vrf XXXXX
 router-id 1.2.3.4
 capability vrf-lite
 area 1.2.3.0 authentication message-digest
 network 1.2.3.0 0.0.0.255 area 1.2.3.0

A good lessen for myself!

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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!

• Cisco Reading List

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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).

• CNA-02-001.pkt, (Backup Link)
• CNA-02-001-sol.pkt (solution for reference), (Backup Link)

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!