Dear friends,
When I tried to simulate the ATM network for Ammavan Thomas regarding his question here about the MPLS over PPP over ATM I came across a strange problem.
I was experimenting with two IOS versions for 7200 series on dynamips. I have used the same topology - two routers connected back to back using their ATM1/0 interface.
I have used the following configuration:
R1:
interface ATM1/0
no ip address
no atm ilmi-keepalive
!
interface ATM1/0.1 point-to-point
no snmp trap link-status
pvc 0/61
encapsulation aal5snap
protocol ppp Virtual-Template1
!
!
interface Virtual-Template1
ip address 10.0.0.1 255.255.255.0
On R2:
interface ATM1/0
no ip address
no atm ilmi-keepalive
!
interface ATM1/0.1 point-to-point
no snmp trap link-status
pvc 0/61
encapsulation aal5snap
protocol ppp Virtual-Template1
!
!
interface Virtual-Template1
ip address 10.0.0.2 255.255.255.0
Now, when I use this configuration on IOS 12.3, everything works just fine and there is full IP connectivity between the two routers. The show ip interface brief on R1 shows this:
R1#show ip int brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 unassigned YES unset administratively down down
ATM1/0 unassigned YES manual up up
ATM1/0.1 unassigned YES unset up up
Virtual-Access1 unassigned YES unset up up
Virtual-Access1.1 10.0.0.1 YES TFTP up up
Virtual-Template1 10.0.0.1 YES manual down down
Virtual-Access2 unassigned YES unset down down
However, when I apply the very same configuration on IOS 12.4, there are problems. Note the show ip interface brief on R1 again:
R1#show ip int brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 unassigned YES unset administratively down down
ATM1/0 unassigned YES manual up up
ATM1/0.1 unassigned YES unset up up
Virtual-Access1 unassigned YES unset down down
Virtual-Template1 10.0.0.1 YES manual down down
Note that the interface Virtual-Access1 remains down/down. The interfaces Virtual-Access1.1 and Virtual-Access2 are not created at all. The PPP negotiation never takes place. Simply - the PPP session never comes up.
Is there anything that should be configured differently on the 12.4 version? Am I doing any mistake here? Any hint or suggestion is greatly appreciated!
Best regards,
Peter
