Lab problems

[TranceSphere]

I'm currently setting up my ccna lab and im having problems with it.

I have 4 routers:

2513
2611
2620xm
3640

The 2513, 2611 and 2620xm are connected to the 3640 using a nm-4t. The clock rates have been set on the 3640 to 2016000 (i've tried lower values).

When I use hdlc for encapsulation I keep on getting timeouts:


Sending 20, 100-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds:
!..!..!..!..!..!..!.
Success rate is 35 percent (7/20), round-trip min/avg/max = 4/4/8 ms


But when I change the encapsulation to ppp its perfect on all the routers, no timeouts.

What could be causing this?


edit: when I remove a router (any router) the timeouts go away, so i've been swapping the cables around/trying different port combinations. But I still get timeouts with 3 routers connected using hdlc.

 

[QHalo]

Have you run a debug ip packet and then run that ping?

 

[xphil3]

Need a ton more info,

This is a hub and spoke design?
Is routing taking place? dynamic or static?
Where are you experiencing the timeouts?
Are all routers seeing the same exact packet loss?
What debugs have you done?
what does a traceroute look like?

Some recommendations:
Change the timeout to 1 second, what happens?
Change the timeout to 5 seconds, what happens?
Run
debug ip packet det
debug ip icmp

Packet loss could be caused by many many things, its just strange that you dont notice it with ppp although hdlc has almost tripple the overhead that ppp has.