VLSM IPv4 addressing Topology Design

[newbienoob]

Hi. I need some help understanding the question and how to execute it. 

Question:

Assume that ‘Advanced Integrated Electronics (AIE)’ is a Malaysian semiconductor manufacturing company. The company's operations are divided into two main divisions: Product-type Division and Functional Division. In the product-type division, we have groups based on Data Centre, IOT, Software Development, and Memory Solutions Development. In the Functional Division, we have groups based on Administration, Human Resources, Networks, Legal Services, Finance, and Security.

Groups based on Product-type Division are distributed in Penang and Johor Bahru. Groups based on Functional Division are distributed at Shah Alam and Petaling Jaya. Groups based on both Product-type and Functional Divisions are available in Cyberjaya. 

AIE employs 310 staff, combined in all its branches. Assume that one host is required for each employee. The number of hosts required per group can be shared between multiple branches containing the specific group.

Data used:

IP address Block	Divisions	Number of employees/hosts
120.192.8.0/22	Data Centre	64
	IOT	24
	Software Development	68
	Memory Solutions Development	32
	Administration	22
	Human Resources	14
	Networks	40
	Legal Services	10
	Finance	16
	Security	20

So based on the question "Groups based on Product-type Division are distributed in Penang and Johor Bahru. Groups based on Functional Division are distributed at Shah Alam and Petaling Jaya. Groups based on both Product-type and Functional Divisions are available in Cyberjaya."

So I divide it like this:

State	Division	Host Required
Penang	Software Development	68
	Data Centre	64
Johor Bahru	IOT	24
Shah Alam	Administration	22
	Human Resources	14
Petaling Jaya	Network	40
	Legal Service	10
Cyberjaya	Memory Solution Department	64
	Finance	16
	Security	20

Is this correct or should I share all the divisions in Cyberjaya? If I have to share all the divisions in Cyberjaya let's say both Penang and Cyberjaya have a Software Development division, do I share the host required too like 34 for Cyberjaya and 34 for Penang?

[Giuseppe Larosa]

Hello @newbienoob ,

given the following scenario

>>

Groups based on both Product-type and Functional Divisions are available in Cyberjaya.

AIE employs 310 staff, combined in all its branches. Assume that one host is required for each employee. The number of hosts required per group can be shared between multiple branches containing the specific group.

>> Is this correct or should I share all the divisions in Cyberjaya? If I have to share all the divisions in Cyberjaya let's say both Penang and Cyberjaya have a Software Development division, do I share the host required too like 34 for Cyberjaya and 34 for Penang?

I would say that Cyberjaya should have IP subnets and corresponding VLANs for all groups .

People using a laptop can move from a site to another one. So you cannot simply divide by 2 the number of users in a group. And you need to leave some space for growth in each user group.

Hope to help

Giuseppe

[Martin L]

Looks like you are on good track; 68, 64, 40 ? 

VLSM project is about taking large block (of /22 assigned) and dividing into smaller blocks based on size of network IPs requirement (aka nodes or end users). You start with the larger block and move towards smaller ones -  and on the way - figuring out the number of subnets and size of each;  This is because a larger block can be spliced into smaller ones. In other words, /22 includes several /24s, where each of those /24s can be further divided into smaller ones, i.e./26s, and so on ending with /30s -if required for p2p links.  (/31 can be used but it is not used by Cisco for purpose of CCNA cert) 

What mask (or slash /?) gives u a network for 68 hosts, then 64, 40, 24, etc. ?

Update: I have shared pdf with VLSM process at CLN ;  - link updated; get pdf; it may help u 

Regards, ML
**Please Rate All Helpful Responses **

[Richard Burts]

The OP needs to assign subnets for groups of employees. I would suggest that the first step should be to determine the number of addresses required in each subnet. It might help if we remember that the size of subnets uses numbers that are powers of 2. So subnet sizes might be 4, 8, 16, 32, 64, 128. (note that the department that has 64 employees can not use a 64 subnet but would require a 128). Once you have the size of each subnet then you assign subnets for each group. Martin has suggested assigning subnets starting with the largest groups and working down to the smallest groups. I find that approach works quite well.

[paul driver · Accepted solution]

Hello
Based on your OP you would require 340 hosts spanning 10 vlans.
See attached example..