Build It in Layers

One of the best thing about having all of the incredible Guest Speakers in the CCIE R&S Lab Fundamentals and Written Bootcamp is you get to see who agrees with your approach, and who does not.

A week or so ago – we were very blessed to have one of the brightest minds in the CCIE space – Marko M from IPexpert. I not only learned how to pronounce his last name, I also discovered that he agreed with my strategy recommendation for students about how to build a complex network configuration in layers. In this post, I thought I would demonstrate this approach.

Perhaps you need to run OSPF over two Frame Relay neighbors and you need to engage area 0 authentication for these neighbors. While some would build the entire configuration and then troubleshoot any problems, I prefer to build in layers and verify as I go along. If something does go wrong – it is so much easier for me to isolate the issue and correct it. Sure, I might not go as fast as someone else, but I certainly go fast enough to pass. Let us see…

The Frame Relay

R2

R2(config)#interface s0/0
R2(config-if)#shut
R2(config-if)#encapsulation frame-relay
R2(config-if)#no frame-relay inverse-arp
R2(config-if)#ip address 10.10.10.2 255.255.255.0
R2(config-if)#frame-relay map ip 10.10.10.4 204 broadcast
R2(config-if)#no shutdown

R4

R4(config)#interface s0/0
R4(config-if)#shutdown
R4(config-if)#encapsulation frame-relay
R4(config-if)#no frame-relay inverse-arp
R4(config-if)#ip address 10.10.10.4 255.255.255.0
R4(config-if)#frame-relay map ip 10.10.10.2 402 broadcast
R4(config-if)#no shutdown

Lab Step Verification

R4

R4(config-if)#do ping 10.10.10.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.10.10.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/8/12 ms

The OSPF

R2

R2(config-if)#router ospf 1
R2(config-router)#network 10.10.10.2 0.0.0.0 area 0
R2(config-router)#neighbor 10.10.10.4

R4

R4(config-if)#router ospf 1
R4(config-router)#network 10.10.10.4 0.0.0.0 area 0
R4(config-router)#neighbor 10.10.10.2

Lab Step Verification

R4#*Mar  1 00:28:18.551: %SYS-5-CONFIG_I: Configured from console by console
R4#*Mar  1 00:29:41.531: %OSPF-5-ADJCHG: Process 1, Nbr 10.10.10.2 on Serial0/0 from LOADING to FULL, Loading Done

The OSPF Authentication

R2

R2(config)#router ospf 1
R2(config-router)#area 0 authentication message-digest
R2(config-router)#interface s0/0
R2(config-if)#ip ospf message-digest-key 1 md5 cisco

R4

R4(config)#router ospf 1
R4(config-router)#area 0 authentication message-digest
R4(config-router)#interface s0/0
R4(config-if)#ip ospf message-digest-key 1 md5 cisco

Lab Step Verification

*Mar  1 00:54:11.363: %OSPF-5-ADJCHG: Process 1, Nbr 10.10.10.2 on Serial0/0 from LOADING to FULL, Loading Done

Something else worth noting here is how the console messages often provide the required verification. It could not be easier!

Anthony Sequeira CCIE, CCSI
Twitter: @compsolv
Facebook: http://www.facebook.com/compsolv

Tags: CCIE, CCIE R&S, ccie r&s frame relay, exam, lab, practice, Strategy, training