zNetLaB › Guided labs › Service Provider
VRF-lite — two customers, one router, the same addresses
Service Provider Intermediate 3 devices 5 checked tasks 100 points Plan lab
Two customers both use 10.0.0.0/30 to reach the provider edge. Put each customer’s interface in its own VRF so the overlap stops mattering, and prove the global table knows nothing about either. You build it in a browser, type real commands at each device, and every task below is
checked against the running configuration — so you find out it is wrong before anybody else does.
Open this lab in the simulator
The simulator runs in your browser with nothing to install. This lab is part of the full simulator: open it free for 7 days with a new account, then with a plan. It needs an account, which keeps your progress.
The scenario
Two customers both use 10.0.0.0/30 to reach the provider edge. Put each customer’s interface in its own VRF so the overlap stops mattering, and prove the global table knows nothing about either.
Your role: an engineer in the provider’s network operations centre. Level: Intermediate Done when: all 5 goals show as passed (100 points).
Network status
Devices: 3 routers, cabled as drawn. No Layer 1 or Layer 2 faults: every link is connected and up. CE-Alpha starts with addresses (G0/0 10.0.0.2/30). CE-Bravo starts with addresses (G0/0 10.0.0.2/30). PE starts with an empty configuration. Known problems
None: nothing is misconfigured. The network is simply not finished: what the goals list is what you have to build or secure. Goals
Customer Alpha’s interface is in VRF ALPHA (20 pts) Customer Bravo’s is in VRF BRAVO (20 pts) Both VRF tables hold 10.0.0.0/30 (25 pts) The global table holds neither (15 pts) Each customer reaches its own provider edge (20 pts) The activity, in order
Customer Alpha’s interface is in VRF ALPHA Why: Each goal is a state the lab can check on the running device. Verify with: show running-config Customer Bravo’s is in VRF BRAVO Why: Each goal is a state the lab can check on the running device. Verify with: show running-config Both VRF tables hold 10.0.0.0/30 Why: Each goal is a state the lab can check on the running device. Verify with: show running-config The global table holds neither Why: A route that should not exist is a leak or a loop waiting to happen. Verify with: show ip route Each customer reaches its own provider edge Why: A ping needs a route in BOTH directions. This is the end-to-end proof that everything before it worked. Verify with: ping 10.0.0.1 Tips
Work in the order given: later goals depend on the earlier ones. After every change, run the verify command before moving on; do not guess. Stuck? Read the verify output first. It names the interface, neighbour or route that is wrong. Why this matters
Two customers both use 10.0.0.0/30 to reach the provider edge. Put each customer’s interface in its own VRF so the overlap stops mattering, and prove the global table knows nothing about either.
What you will be able to do
Customer Alpha’s interface is in VRF ALPHA
Customer Bravo’s is in VRF BRAVO
Both VRF tables hold 10.0.0.0/30
The global table holds neither
The network
ISR 4331, ISR 2911 — 3 devices in all, already cabled.
Gi0/0/0 Gi0/0 10.0.0.2/30 Gi0/0/1 Gi0/0 10.0.0.2/30 PE CE-Alpha CE-Bravo Drawn from this lab: devices, cables, ports and the addresses already set. Device Model Address already set
PE ISR 4331 configure it CE-Alpha ISR 2911 configure it CE-Bravo ISR 2911 configure it
Cabling
PE Gi0/0/0 ↔ CE-Alpha Gi0/0 PE Gi0/0/1 ↔ CE-Bravo Gi0/0
What is configured at the start
These are already configured when the lab opens — including, where this is a troubleshooting lab, the fault itself:
CE-Alpha interface g0/0
ip address 10.0.0.2 255.255.255.252
no shutdown
exit CE-Bravo interface g0/0
ip address 10.0.0.2 255.255.255.252
no shutdown
exit PE interface g0/0/0
no shutdown
exit
interface g0/0/1
no shutdown
exit Tasks, and how each one is checked
Every task is decided by reading the live network — a neighbour in FULL, a ping that succeeds, a line in the running configuration — not by looking for a keyword you typed. The same command shows you what the lab sees.
# Task Pts How to verify it yourself
1 Customer Alpha’s interface is in VRF ALPHA 20 Checked automatically against the device’s live state (vrfIface). 2 Customer Bravo’s is in VRF BRAVO 20 Checked automatically against the device’s live state (vrfIface). 3 Both VRF tables hold 10.0.0.0/30 25 Checked automatically against the device’s live state (vrfRoute). and Checked automatically against the device’s live state (vrfRoute). 4 The global table holds neither 15 On PE: show ip route does not list 10.0.0.0/30. 5 Each customer reaches its own provider edge 20 On CE-Alpha: ping 10.0.0.1 must succeed. and On CE-Bravo: ping 10.0.0.1 must succeed.
Stuck? Ask the coach
Tell the coach what you see or what you tried. It gives you a hint, not the answer, the way a senior engineer would. Included with a free trial or any plan.
Ask the coach
Reference solution
Try it yourself first — the lab checks your work either way. This is one configuration that makes every task pass, device by device:
PE vrf definition ALPHA
rd 65000:1
address-family ipv4
exit
exit
vrf definition BRAVO
rd 65000:2
address-family ipv4
exit
exit
interface g0/0/0
vrf forwarding ALPHA
ip address 10.0.0.1 255.255.255.252
no shutdown
exit
interface g0/0/1
vrf forwarding BRAVO
ip address 10.0.0.1 255.255.255.252
no shutdown
exit Where this is examined
This lab practises these topics in the zNetLaB certification courses:
Related labs
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