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General considerations
Internet customers with fixed connections (leased line or frame-relay) require a CPE (Customer
Premises Equipment) router to interface between the IP-Plus PoP and their own network. IP-Plus
Internet Services offers with IP-Plus Direct Access two CPE possibilities:
- IP-Plus Managed CPE
- Unmanaged CPE
In the case of a Managed CPE, IP-Plus takes responsibility for configuring the CPE to work with
the IP-Plus network and the customer's own environment.
In the case of a Unmanaged CPE, there is no dynamic routing between the IP-Plus network and the
CPE, to avoid the possibility of a misconfigured CPE advertising false routes into the Internet.
Static routes are configured in the IP-Plus PoP which indicate the CPE as the path to reach the
IP addresses assigned to the customer. The CPE does not receive any dynamic routes from the
IP-Plus network - the customer should configure a static default route in the CPE which sends
all packets with destinations not in the CPE's routing table to the IP-Plus network.
There are restrictions on the type of CPE router that can be connected to the IP-Plus network.
Currently, only Cisco Systems routers equipped with software release 10.2 or higher are accepted.
The following sections show how to configure a Cisco router for the static default routing and
the leased-line (HDLC) or frame-relay encapsulation.
IP-Plus Direct Access (leased Line connection) to IP-Plus PoP
The following configuration commands must be included into the CPE configuration file
- interface Serial X
- ip address164.128.x.x 255.255.255.252
- ip classless
- ip route 0.0.0.0 interface serial X
where:
- X is the serial port number for the IP-Plus Internet Service
- 164.128.x.x is the IP address of the serial port supplied to the customer by IP-Plus
Frame-Relay connection
The following configuration commands must be included into the customer's router configuration
file:
- interface SerialX
- no ip address
- encapsulation frame-relay IETF
- interface SerialX.1 point-to-point
- ip address 164.128.x.x 255.255.255.252
- frame-relay interface-dlic yyyy broadcast IETF
- ip classless
- ip route 0.0.0.0 int s X.1
where:
- X is the designation of the physical serial port used for IP-Plus Internet Service
- 164.128.x.x is the IP address of the frame-relay PVC supplied by IP-Plus
- yyyy is the frame-relay DLCI number supplied by IP-Plus
Note that it will also be necessary to arrange the routing within the customer's network to
enable access to the Internet for host machines.
In the simplest case all the hosts are on a single LAN connected to the CPE. Usually all that
has to be done is to configure the LAN IP address of the CPE router as the default-gateway
address in the hosts. In some cases it may be necessary to arrange for the default route
generated in the CPE to be propogatedto host machines via a routing protocol such as RIP.
If the customer's network contains several LANs interconnected via routers, then the default
route generated in the CPE must be re-distributed into whatever routing protocol is used between
the customers routers. In this way all parts of the customer's network are informed about the way
to reach the Internet automatically. Hosts on the LANs can be either configured with their local
router as default-gateway, or they may participate in the routing process directly.
Example Cisco Configuration
The following example configuration is for a router connected via IP-Plus Direct Access (leased
line) to the IP-Plus PoP, and with RIP running in the customer's environment.
hostname <hostname>
!
interface ethernet0
ip address 194.209.50.1 255.255.255.0
! IP-Plus has allocated the C-class address 194.209.50.0 to this customer
! The LAN port has address 194.209.50.1
! The subnet mask is 255.255.255.0, meaning that all IP host on the LAN are in the same
subnet as ! the Internet CPE
!
interface Serial0
description leased line connection to IP-Plus
ip address 164.128.96.32 255.255.255.252
! IP-Plus has allocated the address 164.128.96.32 as the serial port address
!
interface Serial1
no ip address
!
router rip
network 194.209.50.0
! RIP is used to communicate with other LANs within the customer's network
!
passive interface serial 0
! do not send RIP updates to IP-Plus
!
redistribute static subnets
default-metric 1
! causes static default route to be advertised into the customer's network via RIP
!
distance 255
! in general, do not accept RIP updates from other routers in the customer's network
!
distance 120 194.209.50.2
! accept RIP updates from address 194.209.50.2, which is the router leading to other parts
of the customer's network
!
ip classless
! Enable classless routing (otherwise network 164.128.0.0 will be unreachable
!
ip route 0.0.0.0 0.0.0.0 serial 0
! Static default route indicating path to Internet via IP-Plus
!
no ip source-route
! Security measure: disables source routing to prevent address-spoofing attacks
!
enable password <password>
!
service password-encryption
!
line console 0
password <password>
line aux 0
password <password>
line vty 0
password <password>
line vty 1
password <password>
line vty 2
password <password>
line vty 3
password <password>
line vty 4
password <password>
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