Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

  • Congratulations John Tel on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!

Configuring interface FastEthernet 0/1 3

Status
Not open for further replies.

AaronBeau

MIS
Jan 29, 2008
89
US
I would like to start by saying I am not a Cisco guy. With that in mind, here is what I am trying to accomplish.

My FastEthernet 0/1 interface needs to be configured to allow our 18 remote locations to connect back to us. Previously they all came in through the serial interface.

I am not sure if I am going to explain this correct, but this is what I am trying to program:
FastEthernet0/1:0 10.0.10.1
FastEthernet0/1:1 10.0.11.1
....up to.....
FastEthernet0/1:17 10.0.28.1

Any guidance would be greatly appreciated.
 
That's exactly right. This is all assuming that all of your Metro E connections are on the same LAN subnet, which is almost certainly the case.
 
I think you're well ahead of the curve if this is only the second time you've really had to touch a router!

I don't know what the routing is going to look like on those remote routers, though. Do they also have two Fast Ethernet interfaces? I seem to recall that those only have one Fast Ethernet interface.
 
The Linksys routers are 10/100 so I should be all set with the remote sites.
 
Can you have more than one VLAN on those routers? You'll want to put the WAN interface into a different VLAN and keep it separate from the rest of the LAN traffic.

How are these things working now? I thought that those routers didn't have serial interfaces, yet they're talking serially to the main router now.
 
Sorry for jumping in so late on this, but I have several of these types of networks running.

You are very close, just need some a few more routing changes.


CORPORATE

The Cisco router FE0/0 interface should be set up as follows:
[blue]
interface FastEthernet0/1
ip address 10.0.0.1 255.255.255.0
[/blue]
You're going to need static routes to point back to the remote sites:
[blue]
ip classless
ip route 0.0.0.0 0.0.0.0 192.168.1.254
ip route 192.168.10.0 255.255.255.0 10.0.0.10
ip route 192.168.11.0 255.255.255.0 10.0.0.11
ip route 192.168.12.0 255.255.255.0 10.0.0.12
ip route 192.168.13.0 255.255.255.0 10.0.0.13
ip route 192.168.14.0 255.255.255.0 10.0.0.14
ip route 192.168.15.0 255.255.255.0 10.0.0.15
ip route 192.168.16.0 255.255.255.0 10.0.0.16
ip route 192.168.17.0 255.255.255.0 10.0.0.17
ip route 192.168.18.0 255.255.255.0 10.0.0.18
ip route 192.168.19.0 255.255.255.0 10.0.0.19
ip route 192.168.20.0 255.255.255.0 10.0.0.20
ip route 192.168.21.0 255.255.255.0 10.0.0.21
ip route 192.168.22.0 255.255.255.0 10.0.0.22
ip route 192.168.23.0 255.255.255.0 10.0.0.23
ip route 192.168.24.0 255.255.255.0 10.0.0.24
ip route 192.168.25.0 255.255.255.0 10.0.0.25
ip route 192.168.26.0 255.255.255.0 10.0.0.26
ip route 192.168.27.0 255.255.255.0 10.0.0.27
ip route 192.168.28.0 255.255.255.0 10.0.0.28
[/blue]
All Corp DHCP should have the Cisco's FE0/0 (192.168.1.1) as the default gateway.

I am assuming that 192.168.1.254 is separate device that accesses the internet. You'll have to put static routes in that as well. All those static routes should point to the Cisco FE0/0 (192.168.1.1).


REMOTE SITES

All DHCP should point to the LAN interface of the WRT54G for the default gateway.

The WRT54G WAN interface IP address should correspond to the routing table above.

The WRT54G should have 10.0.0.1 as it's default gateway.

You'll have to make sure all firewall functions are turned off.

I'm not sure about the DD-WRT firmware mod, but the WRT54G has 2 modes of operation "router" and "gateway", you don't want gateway mode because then all traffic is NAT'd.

One other thought...
I believe the DD-WRT mod of the Linksys routers are capable of RIP.
You could get rid of all the static routes in all the devices by enabling RIP on everything.
RIP has it's drawbacks; all devices send out the entire routing table every 30 seconds which can generate some traffic, but you network is relatively small and you have enough bandwidth available, I'd consider it.

I think that's everything, let us know how it works out.

MCSE CCNA CCDA
 
I believe they will accept multiple VLANs. Currently we have old (10 years old) Cisco 1700 routers at each remote site.

The plan with this Metro Ethernet connection is to next roll out VoIP at all our locations. Would the RIP traffic generate too much traffic for that? Also is RIP hard to configure, as I said I am a Systems guy so I don't want to attempt something too far over my head.
 
RIP is easy to configure and won't generate too much traffic with a network your size. You'd basically use the same commands I gave you for EIGRP, except the first command is "router rip" instead of "router eigrp 1".
 
He'll want version 2 RIP for the 24 bit masks for 172.x.x.x and 10.x.x.x

Burt
 
Yes, RIPv2 for classless routing.

As far as VoIP...
You have plenty of bandwidth, each VoIP session only consumes 84k (with overhead) of bandwidth.
However, you will probably want to implement some form of QoS.
You can implement QoS based on several factors: MAC address, IP address, VLAN, DiffServ, Dot1p, etc.
You're probably going to be restricted to what the DD-WRT routers will support.

MCSE CCNA CCDA
 
I talked to the network engineers from our Metro Ethernet connection, and I got some more information and some terminology!!

They want the FastEthernet0/1 interface divided up into Sub Interfaces. The reason they wanted it that way was to avoid network broadcast storm in the event that a router goes bad (not too sure but it sounded legit).

 
It may be legit, but I don't understand it. If you break it up into subinterfaces, that means that each subinterface is going to be on its own VLAN, which means they're doing trunking to you. It also has some ramifications regarding your IP addressing scheme.
 
OMG - this definitely is a Monday!
I tried breaking it up into subinterfaces and when attempting to put the IP address on it I get the following error:
Code:
conf t
int fa0/1.1
ip address 10.0.10.1 255.255.252

% Configuring IP routing on a LAN subinterface is only allowed if thatsubinterface is already configured as part of an IEEE 802.10, IEEE 802.1Q,or ISL vLAN.

You said:
that means that each subinterface is going to be on its own VLAN, which means they're doing trunking to you

That is a foreign langauge to me, could you explain this a little more?
 
That means you have to configure it as a trunk port and then add "encapsulation dot1q" to the subinterface. I'm very unclear about why they want it configured that way, though.

Are they doing trunking on this link? If so, is each remote site coming in on its own VLAN? If that's the case, each VLAN will have its own LAN subnet and subinterface.
 
For some reason the router doesn't recognize 'encapsulation'.

Here is what was explained to me in the meeting today. After I told them how I reconfigured everything (the way we discussed in here) they said that they didn't want the design that way because of the possibility of a broadcast storm. They said they wanted all the traffic between the Remote Sites separated from each other on the back to corporate.

Then I suggested using RIP, but they said that a Dynamic routing table wouldn't make much sense for a network with 1 internet connection with remote sites that aren't going to be changing.

PS - I need a new job with a real IT department, anyone know of something?
 
I'm not understanding this at all...you have several locations, each with their own subnet. Don't they each have their own router??? Why are you wanting to put 18 IP addresses on one interface???
If all your IP addresses are static, with no redundancy configured, you may as well have static routes rather than using a routing protocol. But that means you can't have redundancy!
Please explain your topology!

Burt
 
I'm with you, Burt. I just don't understand how they have this designed under the hood. It almost sounds like each remote site is on its own VLAN and they are trunking to the main site. I've only seen a couple of "point-to-point" Metro E connections, so I have no idea if that's a common configuration or not.
 
He's probably running IP Base code, since their is no choice for encapsulation, or it may be a router that does not support trunking, like a 1720...
"We are using a new ISP which is handing us Ethernet at each of our locations. Therefore the I wanted the Cisco FastEthernet0/1 to be divided up into 18 different IP's
10.0.10.1 /30 - 10.0.28.1 /30

And the IP Address on the router at each location will be:
10.0.10.2 /30 - 10.0.28.2 /30"

So, why put all the sites' IP addresses on your fa0 interface??? It just needs one like the rest, and each one seems to be point-to-point, with the routing configured with a 24 bit mask! The 30 bit mask makes no sense to me in this situation---not needed at all! Not with a private IP addressing scheme!

Burt
 
My FastEthernet 0/1 interface needs to be configured to allow our 18 remote locations to connect back to us. Previously they all came in through the serial interface."

fa0/0(10.1.1.1/24)------site1(10.1.1.2)----site3(10.1.1.3)etc...

With all the routers having routes to eachother, this is all that's needed!

Burt
 
- Each Site has it's own router.

- There is no redundancy.

- I was told to divide the interface into subinterfaces to
separate all the traffic from each remote site back to corporate.

- I am not 100% sure what trunking at the main site means. But I understand that the connection between Corporate and each Remote site was supposed to be isolated.
 
Burtsbees, that is how I last configured the router. However, I was told today in a meeting that it was strongly advised not to program it that way in the event of a router going bad and creating a broadcast storm.

Previously, they all came in on the Serial interface, but that had subinterfaces for each location.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top