ADSL WAN Connections
Troubleshooting the ADSL Connection
ppp 1 is UP
Configuration:
Keep-alive is set (10 sec.)
No multilink
MTU = 1492
No authentication
IP is configured
192.168.1.20
Link thru atm 1.1 is UP; LCP state is OPENED, negotiated MTU is 1492
Receive: bytes=3596, pkts=442, errors=0
Transmit: bytes=3508, pkts=292, errors=0
5 minute input rate 624 bits/sec, 1 packets/sec
5 minute output rate 496 bits/sec, 1 packets/sec
Bundle information
Queueing method: fifo
HDLC tx ring limit: 0
Output queue: 0/1/200/0 (size/highest/max total/drops)
IP is DOWN, IPCP state is REQSENT
LLDPCP State is REQ SENT
7-54
When you view the status of the PPP interface, you must ensure that both the
interface and the Network Layer protocol are up. For example, Figure 7-25
shows a PPP interface that is up. However, the user cannot send traffic over
the link. If you look more closely at Figure 7-25, you can see the reason: the
Network Layer protocol—IP—is down.
First, make sure the interface is up
255.255.255.0
Figure 7-25. The PPP interface is up, but IP is down.
To determine why IP is down, use the debug ppp commands. Table 7-8 lists
the debug commands you can use to monitor PPP interfaces.
Table 7-8.
debug ppp Commands
Command
debug ppp verbose
debug ppp errors
debug ppp negotiations
debug ppp authentication
undebug all
Next, ensure that IP is up
Explanation
displays detailed information about all PPP
frames as they arrive on the PPP interface
displays error messages relating to PPP
displays events relating to link negotiation;
shows if links protocols are able to open; and
reveals when negotiations between two PPP
peers fail
displays real-time messages relating to PAP
and CHAP
turns off debug messages