Cisco small router info

Background

Our project distributes data to some sites from a core 7507 router, at the other end are much smaller routers which convert the incoming E1 X21 serial lines back to ethernet to distribute to the local computers. These are either 1601, 1720 or 2500 series models depending on which one came out of the box of bits first, or if the site has a rack mount cabinet (2500 series).

1601

1601 series is basically a fixed hardware config with 1x60 pin serial port socket and 1x 10Mb/s ethernet port as well as the standard RJ45 console port. I think other models have different combinations of ports, but all ours are as above.
The power supply is an external unit which connects via a 6 pin mini din plug and can be quite unreliable if the cable clamp is missing from the router.

1720

1700 series is a more modular router, it has 2 WIC (Wan Interface Card) slot for the serial interface and a 10/100 ethernet port. Also the LEDs on the front panel can actually be seen when it is in use. All ours had a 60 pin serial port wic fitted, an option exists for an ISDN wic for dial back links if the serial line should fail. The power supply is an external unit with I think a Cisco propriatory connector fitted. At least it has a latch to prevent accidental removal.

2501

2500 series routers are an old, retired model now but there are many still in use and readily available from ebay etc. They are rackmountable and have an internal power supply fitted. We used a few 2501's which have 2x 60pin serial connectors, 1x AUI ethernet, 1x ISDN basic rate and 1x console RJ45 port. 2520 is similar but it has 2x60pin synchronous and 2x60pin asychronous serial ports and an RJ45 ethernet port.

Configuration

The software config is similar in all cases, except that 10/100Mb/s ethernet ports are called fa0 etc whilst 10Mb/s ports are eth0 etc. Below is a config which connects back to the core via serial line at E1, and to local ethernet. The serial link is a /30 or .252 mask and the local ethernet is a /24 or .0 mask. Some values have been changed for reasons of confidentiality but do not affect the config.

SiteRouter1_1601R#sh run
Building configuration...
 
Current configuration:
!
version 12.0
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname SiteRouter1_1601R
!
enable password guessme
!
ip subnet-zero
no ip finger
!
!
!
interface Loopback0
 ip address 192.168.251.3 255.255.255.255
 no ip directed-broadcast
!
interface Ethernet0
 description *** Link 12 Port IBM Hub 10M ***
 ip address 192.168.3.1 255.255.255.0
 no ip directed-broadcast
 no keepalive
!
interface Serial0
 description *** Link To Core Ref-no 2M ***
 bandwidth 2000
 ip address 192.168.253.10 255.255.255.252
 no ip directed-broadcast
 encapsulation ppp
 no fair-queue
!
router eigrp 1
 network 192.0.0.0
 network 192.168.0.0
 no auto-summary
!
ip classless
!
snmp-server community notpublic RO
snmp-server community norprivate RW
snmp-server enable traps config
banner login ^CCCC
              Do NOT access this system unless authorised to do so.
 
^C
!
line con 0
 password guessmeaswell
 login
 transport input none
line vty 0 4
 password guessmeaswell
 login
!
end
 
SiteRouter1_1601R#