>топологию нарисуй....и конфиг каждого порта, которые соединяют железки...
Топология: router2620xm по FastEthernet с switch2950(1) по GigabitEthernet с switch2950(2) по FastEthernet с switch2912LRE по LongReachEthernet с switch2950(3) по FastEthernet на сеть.
на router2620xm:
interface FastEthernet0/0
description Link to 2950 (VLAN)
no ip address
speed 100
full-duplex
interface FastEthernet0/0.13
description Link to ****
encapsulation dot1Q 13
ip address ***.***.***.*** ***.***.***.***
на switch2950(1):
interface FastEthernet0/12
description Link to ****
switchport access vlan 3
no ip address
duplex full
speed 100
interface GigabitEthernet0/1
description Link to ****
switchport mode trunk
no ip address
switch2950(2):
interface GigabitEthernet0/1
description Link to ****
switchport mode trunk
no ip address
interface FastEthernet0/1
description Link to Cisco 2912 LRE
switchport mode trunk
no ip address
на switch2912LRE:
interface FastEthernet0/1
description Link to Cisco 2950
switchport trunk encapsulation dot1q
switchport mode trunk
interface LongReachEthernet0/2
description Link to ****
switchport trunk encapsulation dot1q
switchport mode trunk
на switch2950(3):
interface FastEthernet0/1
description Link to Cisco 2950
switchport mode trunk
no ip address
interface FastEthernet0/2
description Link to ****
switchport access vlan 13
no ip address
Причём на switch2950(2) подобно прописанный vlan работает.