VLSM

lab completed in dorm room 10-04

Background

PPC uses the private Class B space 172.16.0.0/16. All hosts were on the same network, causing performance issues — subnetted it with VLSM based on each division's host requirements.

Deliverable 1: VLSM Chart

Name	Hosts Needed	Usable Hosts	CIDR	Increment	Network Address	First Usable	Last Usable	Broadcast
Sales	1200	2,046	/21	8	172.16.0.0	172.16.0.1	172.16.7.254	172.16.7.255
Manufacturing	612	1,022	/22	4	172.16.8.0	172.16.8.1	172.16.11.254	172.16.11.255
Engineering	31	62	/26	64	172.16.12.0	172.16.12.1	172.16.12.62	172.16.12.63
Accounting	24	30	/27	32	172.16.12.64	172.16.12.65	172.16.12.94	172.16.12.95
HR	10	14	/28	16	172.16.12.96	172.16.12.97	172.16.12.110	172.16.12.111

Router-to-router link (N. America ↔ Mumbai): 172.16.12.112/30

Deliverable 2: Build the Network

• Built network from net150Lab6.1.Starter.pkt — router interfaces and static routes were pre-configured; only needed to add PCs and configure IPs/gateways
• Added two PCs per switch: 2nd available IP in the subnet + last valid IP in the subnet (gateway uses the 1st available IP)
  • Sales — gateway 172.16.0.1, SalesFirst 172.16.0.2, SalesLast 172.16.7.254
  • Manufacturing — gateway 172.16.8.1, ManFirst 172.16.8.2, ManLast 172.16.11.254
  • Engineering — gateway 172.16.12.1, EngFirst 172.16.12.2, EngLast 172.16.12.62
  • Accounting — gateway 172.16.12.65, AcctFirst 172.16.12.66, AcctLast 172.16.12.94
  • HR — gateway 172.16.12.97, HRFirst 172.16.12.98, HRLast 172.16.12.110
• Router-to-router serial link (Se3/0): N. America Router 172.16.12.113/30, Mumbai Router 172.16.12.114/30
• Ran PDU tests between divisions — all successful
  • AcctFirst → SalesFirst
  • SalesLast → ManLast
  • HRFirst → EngFirst
  • EngLast → SalesLast
  • HRLast → AcctLast
• Practiced saving router config (Config tab → Save NVRAM), power-cycled both routers (Physical tab), used Fast Forward to restore links
  • Confirmed interface IPs persisted on both N. America Router and Mumbai Router after restart