Cisco terminal server line information

I spend a lot of time on Cisco terminal servers for out of band management of Cisco devices. Cisco's earliest foray into them back in the early '90's were the CS-508 and CS-516. They had a single AUI Ethernet port and either 8 or 16 RJ-45 ports for hooking up Cisco roll cables to the console ports of other Cisco devices. Then came the 2509 and 2511. My personal favorites are the NM-16a and NM-32a modules that fit in 2600 and 3600 series routers. I have a 3640 router with an NM-32a at home.

Terminal Line Numbering

In the Cisco 2509 and 2511, terminal lines are numbered sequentially 1 through 16.

In Cisco 2600 and 3600 modular routers, when using NM-16a and NM-32a modules, Cisco IOS Software reserves 32 line numbers per slot. The AUX port is line 65 on the Cisco 2500, 2600 and 3620 series routers and line 129 on the Cisco 3640. A good way to remember line numbers on the 2600 and 3600 routers with more than one is:

line number = (slot * 32) + unit + 1

so for a 2600 router, you would configure lines on an nm-32a as follows:

ip host r1 2033 10.10.10.1
ip host r2 2034 10.10.10.1
ip host r3 2035 10.10.10.1
ip host r4 2036 10.10.10.1
ip host r5 2037 10.10.10.1
ip host r6 2038 10.10.10.1
ip host r7 2039 10.10.10.1
ip host r8 2040 10.10.10.1
!
interface Loopback0
ip address 10.10.10.1 255.255.255.0
!
line 33 40
no exec
transport input telnet
telnet transparent


For a 3640 router, you would configure lines on an nm-32a like this:

ip host r1 2097 10.10.10.1
ip host r2 2098 10.10.10.1
ip host r3 2099 10.10.10.1
ip host r4 2100 10.10.10.1
ip host r5 2101 10.10.10.1
ip host r6 2102 10.10.10.1
ip host r7 2103 10.10.10.1
ip host r8 2104 10.10.10.1
!
interface Loopback0
ip address 10.10.10.1 255.255.255.0
!
line 97 128
no exec
transport input telnet
telnet transparent
!


Another wise thing to do is change the escape sequence on your terminal server to something unique so you can break out of a terminal session on a remote router to go back to the terminal server or hop on a different terminal session to another box. I use CTRL-W and then x keystrokes. Here is how to configure this on a terminal server:

line vty 0 4 escape-character 23