B-5
CiscouBR924 Software Configuration Guide
OL-0337-05 (8/2002)
AppendixB Using the Cable M onitor Tool
Accessing the Cable Monitor
Step 2 Type in a URL with the IP address assigned to the cable interface on the CiscouBR924 router. This is
typically an address in the service provider’s IP address space.
For example, if the Cisco uBR924 router has been assigned the IP addr ess of 209.165.202.131 by the
service provider, a technician at the headend would use the following URL to access the Cable Monitor:
http://209.165.202.131
If a port number other than the default of 80 has been assigned to the Cable Monitor, that port number
must be included as part of the URL. For example, if the Cisco uBR924 router has been assigned the IP
address of 209.165.202.131 and a port number of 8080 by the service provider, a technician at the
headend would use the following URL to access the Cable Monitor:
http://209.165.202.131:8080
Tip If the router is operating in routing mode, and the cable interface is up, you can also access the Cable
Monitor by entering the IP address for the Ethernet interface into your web browser.
Through the Ethernet Interface when the Cable Interface is Not Operational
When the Cisco uBR924 router loses connectivity with the CMTS at the headend and detects that its
cable interface is not operational, the router automatically switches into a diagnostic mode and does the
following:
•Activates a temporary DHCP server to assign IP addresses in the IP network that is defined by the
IP address and subnet mask given with the ip http cable-monitor command (the default address
pool is the Class C private network 192.168.100.0).
•When a PC or other workstation connected to the router’s Ethernet ports makes a DHCP request, the
router assigns an IP address and default gateway from this address space so that the PC can
communicate with the Cable Monitor on the router.
Note The PC or workstation can be rebooted to force it to make a DHCP request. If using a
Windows95 or Windows98 sy stem, you can also use the winipcfg utility to send a DHCP
release and renew request.
•When the router detects any web server requests, it automatically redirects them to the Cable
Monitor.
•The router’s DHCP server renews these IP addresses every 30 seconds as long as the cable interface
is down.
•When the cable interface is back up, the router returns to normal operation, using the configurat ion
that existed before it switched into diagnostics mode. (At this point, the PC or workstation that
accessed the Cable Monitor can be rebooted to restore its co nfiguration, or you can wait from 30 to
60 seconds for the PC to automatically issue a DHCP renew request. Windows 95 or Windows 98
users can also use the winipcfg utility.)
When the cable interface is down, users at the subscriber site can use the following procedure to access
the Cable Monitor to aid in troubleshooting the problem with the cable network:
Step 1 If necessary, connect a PC to one of the Ethernet ports on the CiscouBR924 router.