no connection between switch 3500 and 3550

[nagalakshmi_n2000]

We have total of 6 switch in that 3500 and 3550 is not commucating to each other. In 3550 5 vlan is configured and it connecting to 3500 throught cross-cable and 3500 is inturn connected to 2 more switch and those are working fine and those belong to same vlan The link sometime comes up and will be down for long time.....

and some time link will never come up.

[andrew.butterworth]

The 3500XL switches do not support DTP so you would have to hard-code the trunking port on the 3550 to 'nonegotiate' as follows:

interface FastEthernet 1/0

switchport mode trunk

switchport trunk encapsulation dot1q

switchport nonegotiate

Obviously make sure the trunks have the same native VLAN and the allowed VLAN list is the same.

Andy

[nagalakshmi_n2000]

but till these date both the switch was working fine without any trunk but why should i truck it now. and 3500 switch is connected to 2900 switch and to 3550 SMI and EMI switch but truck is done only on G0/1 to 3550 SMI switch and truck is not done to 2900 and 3550 EMI. And 2900 is working fine and 3500 switch is not connecting only 3550 EMI switch and in 3550 EMI switch we have 5 vlan that is 192.168.103.0, 192.168.107.0, 192.168.108.0, 192.168.109.0 etc but other switchs not in these vlan that is there belongs to 192.168.102.0 network and there working fine. But from 192.168.102.0 to 192.168.103.0. there are not able to connect nor the link is coming up.

[nagalakshmi_n2000]

but till these date both the switch was working fine without any trunk but why should i truck it now. and 3500 switch is connected to 2900 switch and to 3550 SMI and EMI switch but truck is done only on G0/1 to 3550 SMI switch and truck is not done to 2900 and 3550 EMI. And 2900 is working fine and 3500 switch is not connecting only 3550 EMI switch and in 3550 EMI switch we have 5 vlan that is 192.168.103.0, 192.168.107.0, 192.168.108.0, 192.168.109.0 etc but other switchs not in these vlan that is there belongs to 192.168.102.0 network and there working fine. But from 192.168.102.0 to 192.168.103.0. there are not able to connect nor the link is coming up.