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Diamond, two paths 08 — default routes routing
Enterprise Intermediate 6 devices 5 checked tasks 52 points Plan lab
Scenario — Surat and Kozhikode are joined by two paths, one through Vizag and one through Imphal. Every interface is already addressed. Your job is the routing: use a default route design (default toward the head-end, specific routes only where needed) so every office can reach every other. 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
Surat and Kozhikode are joined by two paths, one through Vizag and one through Imphal. Every interface is already addressed. Your job is the routing: use a default route design (default toward the head-end, specific routes only where needed) so every office can reach every other.
Your role: a network engineer on the enterprise team. Level: Intermediate Done when: all 5 goals show as passed (52 points).
Network status
Devices: 4 routers, 2 PCs, cabled as drawn. No Layer 1 or Layer 2 faults: every link is connected and up. R-Surat starts with addresses (G0/0 10.27.1.1/24, G0/1 172.23.7.1/30, G0/2 172.23.7.5/30). PC-Surat is a host with 10.27.1.10/24, gateway 10.27.1.1. R-Vizag starts with addresses (G0/0 172.23.7.2/30, G0/1 172.23.7.9/30). R-Imphal starts with addresses (G0/0 172.23.7.6/30, G0/1 172.23.7.13/30). R-Kozhikode starts with addresses (G0/0 10.27.2.1/24, G0/1 172.23.7.10/30, G0/2 172.23.7.14/30). PC-Kozhikode is a host with 10.27.2.10/24, gateway 10.27.2.1. Known problems
None: nothing is misconfigured. The routers are simply not finished: the goals list what has to be built. Goals
R-Surat: a route — 10.27.2.0/24 via 172.23.7.2 (8 pts) R-Vizag: 2 routes — default via 172.23.7.1; 10.27.2.0/24 via 172.23.7.10 (8 pts) R-Imphal: 2 routes — default via 172.23.7.5; 10.27.2.0/24 via 172.23.7.14 (8 pts) R-Kozhikode: a route — default via 172.23.7.9 (8 pts) 10.27.1.10 (Surat) reaches 10.27.2.10 (Kozhikode) (20 pts) The activity, in order
On each router write a route for every network it does not touch, using its own neighbour as next hop. Why: The next hop must be an address on a directly connected subnet, or the route never enters the table. Verify with: show ip route Read the routing table of every router and compare it with the plan. Why: The next hop must be an address on a directly connected subnet, or the route never enters the table. Verify with: show ip route Ping from each LAN to every other LAN, in both directions. Why: The next hop must be an address on a directly connected subnet, or the route never enters the table. Verify with: show ip route 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. Common mistake: Pointing the default route at the wrong neighbour address Common mistake: Forgetting the head-end needs specific routes back to every branch Common mistake: Leaving a transit router without the routes to LANs beyond it Why this matters
A branch does not need to know every network. A default route toward the head-end handles everything unknown, while the head-end carries the specific routes — the standard hub-and-spoke design for small sites.
What you will be able to do
Choose between a default route and specific routes
Point a default route at the correct neighbour
Read the gateway of last resort in show ip route
The network
ISR 2911, PC — 6 devices in all, already cabled.
Fa0 Gi0/0 10.27.1.1/24 Fa0 Gi0/0 10.27.2.1/24 Gi0/1 172.23.7.1/30 Gi0/0 172.23.7.2/30 Gi0/2 172.23.7.5/30 Gi0/0 172.23.7.6/30 Gi0/1 172.23.7.9/30 Gi0/1 172.23.7.10/30 Gi0/1 172.23.7.13/30 Gi0/2 172.23.7.14/30 R-Surat PC-Surat 10.27.1.10/24 · gw 10.27.1.1 R-Vizag R-Imphal R-Kozhikode PC-Kozhikode 10.27.2.10/24 · gw 10.27.2.1 Drawn from this lab: devices, cables, ports and the addresses already set. Device Model Address already set
R-Surat ISR 2911 configure it PC-Surat PC 10.27.1.10 / 255.255.255.0 gw 10.27.1.1 R-Vizag ISR 2911 configure it R-Imphal ISR 2911 configure it R-Kozhikode ISR 2911 configure it PC-Kozhikode PC 10.27.2.10 / 255.255.255.0 gw 10.27.2.1
Cabling
PC-Surat Fa0 ↔ R-Surat Gi0/0 PC-Kozhikode Fa0 ↔ R-Kozhikode Gi0/0 R-Surat Gi0/1 ↔ R-Vizag Gi0/0 R-Surat Gi0/2 ↔ R-Imphal Gi0/0 R-Vizag Gi0/1 ↔ R-Kozhikode Gi0/1 R-Imphal Gi0/1 ↔ R-Kozhikode Gi0/2
What is configured at the start
These are already configured when the lab opens — including, where this is a troubleshooting lab, the fault itself:
R-Surat interface g0/0
ip address 10.27.1.1 255.255.255.0
no shutdown
exit
interface g0/1
ip address 172.23.7.1 255.255.255.252
no shutdown
exit
interface g0/2
ip address 172.23.7.5 255.255.255.252
no shutdown
exit R-Vizag interface g0/0
ip address 172.23.7.2 255.255.255.252
no shutdown
exit
interface g0/1
ip address 172.23.7.9 255.255.255.252
no shutdown
exit R-Imphal interface g0/0
ip address 172.23.7.6 255.255.255.252
no shutdown
exit
interface g0/1
ip address 172.23.7.13 255.255.255.252
no shutdown
exit R-Kozhikode interface g0/0
ip address 10.27.2.1 255.255.255.0
no shutdown
exit
interface g0/1
ip address 172.23.7.10 255.255.255.252
no shutdown
exit
interface g0/2
ip address 172.23.7.14 255.255.255.252
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 R-Surat: a route — 10.27.2.0/24 via 172.23.7.2 8 On R-Surat: show ip route 10.27.2.0 shows next hop 172.23.7.2. 2 R-Vizag: 2 routes — default via 172.23.7.1; 10.27.2.0/24 via 172.23.7.10 8 On R-Vizag: show ip route 0.0.0.0 shows next hop 172.23.7.1. and On R-Vizag: show ip route 10.27.2.0 shows next hop 172.23.7.10. 3 R-Imphal: 2 routes — default via 172.23.7.5; 10.27.2.0/24 via 172.23.7.14 8 On R-Imphal: show ip route 0.0.0.0 shows next hop 172.23.7.5. and On R-Imphal: show ip route 10.27.2.0 shows next hop 172.23.7.14. 4 R-Kozhikode: a route — default via 172.23.7.9 8 On R-Kozhikode: show ip route 0.0.0.0 shows next hop 172.23.7.9. 5 10.27.1.10 (Surat) reaches 10.27.2.10 (Kozhikode) 20 On PC-Surat: ping 10.27.2.10 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
Common mistakes
Pointing the default route at the wrong neighbour address
Forgetting the head-end needs specific routes back to every branch
Leaving a transit router without the routes to LANs beyond it
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:
R-Surat ip route 10.27.2.0 255.255.255.0 172.23.7.2 R-Vizag ip route 0.0.0.0 0.0.0.0 172.23.7.1
ip route 10.27.2.0 255.255.255.0 172.23.7.10 R-Imphal ip route 0.0.0.0 0.0.0.0 172.23.7.5
ip route 10.27.2.0 255.255.255.0 172.23.7.14 R-Kozhikode ip route 0.0.0.0 0.0.0.0 172.23.7.9 Where this is examined
CCNA 3.0 default routing; CCNP ENARSI static routing.
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