[c-nsp] GSR and 3750 GE-LX link problem

[Yu-lin Chang]

Hi,

I am recently working on a GE link between a GSR and a 3750.
The GSR side is GBIC-LX, the 3750 side is SFP-LX, and the fiber
is single mode. GSR in 32F, and 3750 is placed in 28F.
 
The GSR config is,
    interface GigabitEthernet1/0
     ip address 10.100.251.221 255.255.255.252
     no ip directed-broadcast
    end

The 3750 config is,
    interface GigabitEthernet1/0/26
     no switchport
     ip address 10.100.251.222 255.255.255.252
    end

When I plug the fiber, GSR and 3750 can see each other
by using "show cdp neighbor". Also, the MAC addresses
are correctly learned by each other.

BUT, the problem is they cannot ping each other.

After many many tried to change negotiation mode and made 
loopback check. There is no problem on the fiber itself,
I am almost been driven to crazy.

Do you ever have such weird problem?


Regards,
Yu-lin