routing protocals over aux ports

[squarefolkdancer]

You can connect two cisco routers (IOS 11.1+) via a rollover/null modem cable between their aux ports and set up serial WAN links between them. Good to get one more connection into a test lab, or as a temporary expedient if a serial port fails. Note that what number the virtual async line gets depends upon the router, on a console server it will be a big number, on a 2520 it will be 4 (I can't explain that). Do a SHOW LINES to find it.

service udp-small-servers
service tcp-small-servers
line aux 0
modem InOut
transport input all
rxspeed 38400
txspeed 38400
flowcontrol hardware
interface Async1
ip address 192.168.0.29 255.255.255.252
encapsulation ppp
bandwidth 1000000
async default routing
async mode dedicated

http://www.cisco.com/warp/public/793/access_dial/auxback.pdf

Here are 4 IP routes (ospf) links between two 2502s:

10.0.0.0/8 is variably subnetted, 3 subnets, 3 masks
O 10.85.11.5/32 [110/2] via 192.168.0.26, 00:03:18, Serial1
[110/2] via 192.168.0.22, 00:03:18, Serial0
[110/2] via 10.85.10.3, 00:03:18, TokenRing0
[110/2] via 192.168.0.30, 00:03:18, Async1

And here is the OSPF neighboring:

Neighbor ID Pri State Dead Time Address Interface
10.86.6.1 1 FULL/DR 00:00:38 192.168.0.30 Async1
10.86.6.1 1 FULL/ - 00:00:37 192.168.0.22 Serial0
10.86.6.1 1 FULL/ - 00:00:37 192.168.0.26 Serial1
10.86.6.1 1 FULL/DR 00:00:37 10.85.10.3 TokenRing0