Learning by Doing: CISCO Certified Network ... - SCN Research

36. IPCP: Install route to 192.168.1.1 (from source)
37. Line protocol on Interface BRI0/0:1, changed state to up
38. Interface BRI0/0:1 is now connected to 5551234 smarts
In line 1 we see our PPP request beginning. Line 2 shows us a request from our source to
start an LCP session. Line 3 shows our destination requesting CHAP password
authentication from the source. Lines 4-7 repeat this process until, in line 8, the CHAP
password authentication times out. (See? Nothing is perfect). In line 9 a request from
our source to start an LCP session is repeated. Line 10 shows our destination requesting
a CHAP password for authentication. Line 11 shows acknowledgement of the CHAP
request. Line 12 shows acknowledgement of the acknowledgement that the information
requesting CHAP password verification, the LCP state is set to open, and the next phase
of PPP establishment starts. Lines 15-20 show us a similar process for verifying the
CHAP password. Line 21 sets our PPP phase (LCP) as up. Line 22 starts our IPCP
negotiation. (This intermingles with CDPCP so I will break them out separately.) Here a
request for the BRI ip address of the destination is requested. Lines 23-28 and 21-33
show the exchange of ip addresses between source and destination. Lines 29-30 and 34-
25 show the CDPCP exchange sequence. Finally our route is installed in line 36. Then
our state is up and connected in lines 37-38.
Physical Layer:
Now lets look at our dialer events and interface states.
kissane#debug dialer
Dial on demand events debugging is on
1. 02:07:54: BR0/0 DDR: Dialing cause ip (s=192.168.1.2, d=192.168.1.1)
2. 02:07:54: BR0/0 DDR: Attempting to dial 5551234
3. 02:07:54: %LINK-3-UPDOWN:Interface BRI0/0:1, changed state to up
4. 02:07:54: %ISDN-6-CONNECT: Interface BRI0/0:1 is now connected
to 5551234
5. 02:07:56: BR0/0:1 DDR: dialer protocol up
6. 02:07:57: %LINEPROTO-5-UPDOWN: Line protocol on Interface
BRI0/0:1, changed state to up
7. 02:08:00: %ISDN-6-CONNECT: Interface BRI0/0:1 is now connected
to 5551234 smarts
Since there is not a lot here let’s just go line by line. Line 1 shows our DDR dialing with
source and destination addresses. Then, in line 2 we dial our destination number set in
our dialer map statement. Our state comes up on our source, we are connected, the dialer
protocol comes up, our state comes up on our destination, and our BRI line is connected.
Not too tough. For a more exacting look combine the debug dialer with debug ppp
negotiation.
429