Cisco student needs help please???

[danabersoch]

Hi guys,

Iam in year one ccna and for my first assignment I have to design a network with:

3 departments each in there own subnet salesX50 hosts, WarehouseX30 hosts and AdminX20 hosts.

There is a lot of other stuff i have to do for the assignment but I'm really struggling to design it.

Its sort of up to me, what demands each department have on the network so Ive put that there are two shared databases and file transfers from the sales department to the warehouse (trying to keep it simple, but not too simple)

At the moment (with packet tracer) I have a generic cisco router with 4 fast ethernet ports where three of which are connected to cisco switches for the stated departments/subnets. (every connection is 100mbps)

I need help with:

Should I stick with cat 5 100mbps utp or because of the 50 hosts in the sales department should I go for cat 6 gigabit or fibre ( just for the connection from the switches to the router to prevent bottlenecks)???

And what are my options with cisco routers, I'm not familiar with them so if you can give me any models I can go research

Please help me any sort of input is really needed, cheers.

[Jon Marshall]

Daniel

Yes you do if you do not have a L3 capable switch. So your config on the router would look something like -

Sales 192.168.11.0 /26 - vlan 10

Warehouse 192.168.11.64 /26 - vlan 11

Admin 192.168.11.128 /26 - vlan 12

the interface on the router is fa0/1

int fa0/1

no ip address

int fa0/1.10

encapsulation dotq1 10

ip address 192.168.11.1 255.255.255.192

int fa0/1.11

encapsulation dotq1 11

ip address 192.168.11.65 255.255.255.192

int fa0/1.12

encapsulation dot1q 12

ip address 192.168.11.129 255.255.255.192

a sales client will have it's default-gateway set to 192.168.11.1

a warehouse client 192.168.11.65

an admin client 192.168.11.129

and as you correctly say in your previous post the port on the switch that int fa0/1 connects into must be configured as an 802.1q trunk.

Jon

[danabersoch]

Cheers Jon

I found the commands on how to config the subinterfaces and Im back on track with this asignment.

I appreciate the advice guys and will be using a lot of it.

I will post progress or failures if or when it occurs!!

[danabersoch]

I have managed to find all the comands and I have come up with a design and all the hosts can ping each other (packet tracer). I have attached my topology diagram for your guys approval, please comment, cheers.

[Joseph W. Doherty]

What you show should work. However, assuming the 2821 had 3 interfaces, you could use it where you have the central switch and save the cost of one switch. Or, if you replaced the central switch with a L3 switch, you likely wouldn't need the separate router. (This would likely provide better LAN routing performance.) Or, if there was also a WAN to deal with, you might retain the 2821 (or smaller router, e.g. 2801, 1841, etc.) to connect to it along with replacing the central L2 switch with a L3 switch. (In the latter, you could either route between the router and the L3 switch, or have both logically on the same subnets. [The last, I'm sure, is confusing but remember L3 switches tend to also be L2 switches.])

If you're wondering which is the "best" design, that depends on the requirments you're attempting to meet.

PS:

Another variation would be to use a L3 switch in the place where you're using the 2821. This would seem stange until you consider that if your uplinks from the switches are gig, the small 8 port 3560 offers 100 Mbps ports but only one gig port. Using it in a router on the stick configuration, like the 2821, might be less expensive than providing a gig port L3 switch to replace the central L2 switch yet offer much faster LAN routing than a 2821 (or any 2800 or 3800 ISR). Real designs also need to account for actual device capabilities.

[danabersoch]

I totally get what you mean with layer three switches and I also get the jist of what they do, BUT I can't use them as Im early on in the course.

Youve got me a bit worried on the fact I wouldnt need that central switch but here is what Ive tried to express in the assignment:

(oh yeah the 2821 has only 2 interfaces abut loads of expansion slots)

The reason for the 2821 over cheaper routers - cos of the gig interfaces for the trunk.

The reason for vlan and routing on a stick - with a router being the central device it would be expensive to add more departments or even a server but as it is there would be no cost (for devices) for new vlans or subnets!

The cost of the central switch is equal to one expansion module for the router

Please tell me if this is enough of a reason to go with this design

[Joseph W. Doherty]

That's good thinking about both the cost of add-on modules for the 2821 vs. a basic switch and later expansion!

However, on your possible later network expansion point, either router ports or another switch could be obtained later. Plus you're assuming new subnets/VLAN would require a new interface. Assuming you needed to split/grow VLAN 10, without adding new equipment, you could trunk up just the VLANs from that physical switch. In otherwords, easy growth without even the need to buy additional interfaces or switches.

Yes, the 2821 has gig interfaces, but the 2821 doesn't ofter the performance to substain gig bandwidth. In fact, it can not really substain 100 Mbps interfaces. It could subtain the perfomance of 2 or 3 10 Mbps interfaces.

To use a Cisco router that can actually support multiple gig bandwidth, you might need the new ASR series. A single gig trunk might be supported by a 7200 with NPE-G2.

If you can't use a L3 switch in your design (yet) that's fine. You're correct, that a central switch by saving interfaces on the router (assuming trunking) might be less expensive than the additional interfaces, but again, you're also sharing that trunked interface's bandwidth. (Always trade-offs.)

[danabersoch]

I got a distinction on this assignment, woooohooo,

thanks for all your imput, helped me out loads!!!