Configuration
By default, all ports on Cisco switches are connected to VLAN1. In our configuration, port 1/0/24 was placed in to VLAN2. An ip address is allocated to each vlan interface and routing is then enabled between VLANs. After several false starts trying to configure bridge groups (BVI) as would have been done on other, older products, this inter vlan routing worked almost too easily.
It was the intention to add some other sites, the next would have been connected to 1/0/23 in VLAN3, but this has not happened yet, so 1/0/23 is left shutdown.
An example config is listed below, several lines have been changed for reasons of confidentiality.
The model in question is a 3750 with 24 10/100MB/s ethernet ports and 2
SFP module slots which were fitted with RJ45 1000MB/s modules
for connection to some servers.
RRR-3750#sh run
Building configuration...
Current configuration : 2031 bytes
!
version 12.1
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname RRR-3750
!
enable password trytoguessme
!
ip subnet-zero
ip routing
!
!
spanning-tree mode pvst
spanning-tree extend system-id
!
!
interface FastEthernet1/0/1
no ip addess
!
interface FastEthernet1/0/2
no ip address
.
.
.
interface FastEthernet1/0/22
no ip address
!
interface FastEthernet1/0/23
description Link to next site
switchport access vlan 3
no ip address
shutdown
!
interface FastEthernet1/0/24
description Link to RRR via 10MB/s line
switchport access vlan 2
mdix auto
no ip address
duplex full
speed 10
!
interface GigabitEthernet1/0/1
description Link to NetWare 6.5 svrnw65-01
no ip address
!
interface GigabitEthernet1/0/2
description Link to Linux mail svrswl-01
no ip address
!
interface Vlan1
description Local ethernet
ip address 192.168.127.1 255.255.255.0
!
interface Vlan2
description WAN link to RRR
ip address 192.168.128.2 255.255.255.252
!
interface Vlan3
description WAN link to next site
ip address 192.168.128.6 255.255.255.252
!
router eigrp 1
redistribute static
network 192.168.127.0
no auto-summary
no eigrp log-neighbor-changes
!
ip classless
ip route .0.0.0 0.0.0.0 192.168.127.7
ip http server
!
!
line con 0
password guessmeaswell
line vty 0 4
password guessmeaswell
login
line vty 5 15
login
!
ntp clock-period 36029231
ntp peer 192.25.0.1
ntp peer 192.25.0.7
ntp server 62.232.4.232
ntp server 62.232.4.233
end
RRR-3750#
Notes:- Several of these units can be stacked so the ethernet ports are called 1/0/1 where the first 1 is the chassis number.
The individual ethernet ports are not given ip addresses, it is the VLANS which have an ip address.
Cisco layer 3 switching
Due to changes in the pricing structure of our WAN telecom links provider, it is cheaper to lease a 10MB/s fibre circuit than a 2MB/s X21 circuit although it is more expensive to setup.
Because of this, the last site we have connected uses a 10MB/s fibre. Instead of terminating this on a router, it is terminated on a layer 3 switch, in this case a Cisco 3750.