Cisco 1700 T1 install

[jsaad]

I have been asked to cut some customers over to a new T1 internet service. Usually I work with cable or DSL. Nonetheless the carrier (XO) gave me this information and the Cisco 1700 is already powered up and configured.

Here is what they gave me (I X'd out the IP for the sake of the customer)

LAN
Customer LAN Block:X1.4.198.48/29
Customer Gateway:X1.4.198.49
Useable Range: X1.4.198.50 - X1.4.198.54
Customer Subnet mask: 255.255.255.248

WAN
Customer WAN Block: X7.109.159.20/30
Customer Side: X7.109.159.22
Network Side X7.109.159.21
WAN Subnet mask: 255.255.255.252

Ordinarily I do a NAT setup. I see they have given a usable range of 5 addresses. I don't see why they need them (no mail server, no web server etc, I suppose I don't have to use them, there may be 10 PCs altogether

My question:
What is the customer WAN block, Customer Side and Network Side. Why do I need this or do I at all need this stuff?

I am just used to the DNS settings and 1 static IP and it everything works. I don't know what all this is and I just want to be a little literate and confident.

which information is most important given my situation and which can I let slide.

any ideas?

 

[lambent]

The WAN block is the subnet of the T1 link connecting the ISP network and your network. For a point-to-point WAN link, the subnet is usually a 30-bit subnet. That's why it has 2 available IP address, Customer Side and Network Side.
I assume that on your router WAN interface you'll need to have the Customer Side IP address and if you decide to pass all Interface traffic out of your WAN interface then you need to configure a default route using the Network Side IP address as the next hop.

 

[JOAMON]

This router is basically setup to connect to the ISP T1 circuit and usually connects to the customers router just as a dsl router would. Lets sub 6 for X

Customer routerDual ethernet router connected to 1700 via crossover)
interface ethernet 0/1 (connects to ISP router ethernet port)
ip address 61.4.198.50 255.255.255.248
ip nat outside
no cdp enable
interface ethernet 0/0 (connects to customer lan)
ip address 192.168.1.1 255.255.255.0
ip nat inside
ip route 0.0.0.0 0.0.0.0 61.4.198.49
ip nat inside source list 102 interface Ethernet0/1 overload
access-list 102 permit ip 192.168.1.0 0.0.0.255 any

With this config make sure that the ISP router does not perform any nat functions.

Hope this helps.

 

[JOAMON]

In a nutshell the WAN block is used by the ISP to connect the router at the CO to the T1 card in the 1700. The LAN block they refer to is a standard 8 block with five useable by the customer. When you look at this from the customer side what the ISP calls the Lan block will actually be considered the WAN on the customers side. Its all in how you look at it. You have five useable ip routeable addresses and need only use the first available for the customers router.