Приветствую, коллеги!

Схема такая:

cisco2921   gi0/0/2----------- gi0/47 trunk
                    trunk             3560G-core2
dot1Q 30                      gi0/52 trunk
  gi0/0.30                          |
    |                                    |
    |                                    |
    |                                    |
gi0/47 trunk                      |
  3560x-core1   trunk-----------
                        gi0/48

Проблема в следующем: корнем rstp для 30 влана является маршрутизатор. Но я не вижу на 35ых заблокированых портов(нет кольца). 3560G-core2 подключена через EHWIC-4ESG, а кора1 через сабик родного интерфейса 2921. Как заставить сабики 2921 участвовать в STP? Если нужна доп информация - спрашивайте, буду рад ответить.

по 2921:
IOS - 15.5(2)T

ВИК:
interface GigabitEthernet0/0/2
description LAN
switchport mode trunk
no ip address
end

interface GigabitEthernet0/0
no ip address
duplex auto
speed auto
!
interface GigabitEthernet0/0.30
description LAN
bandwidth 1000000
encapsulation dot1Q 30
ip address 192.168.30.233 255.255.255.248
ip accounting output-packets
ip nat inside
ip virtual-reassembly in
rate-limit input access-group 2000 1000000 1000000 1000000 conform-action transmit exceed-action drop
!

show spanning-tree  vlan 30

VLAN30 is executing the ieee compatible Spanning Tree protocol
  Bridge Identifier has priority 32768, address c067.af00.12c6
  Configured hello time 2, max age 20, forward delay 15
  We are the root of the spanning tree
  Topology change flag not set, detected flag not set
  Number of topology changes 51 last change occurred 1d01h ago
          from GigabitEthernet0/0/2
  Times:  hold 1, topology change 35, notification 2
          hello 2, max age 20, forward delay 15
  Timers: hello 1, topology change 0, notification 0, aging 300

Port 3 (GigabitEthernet0/0/2) of VLAN30 is forwarding
   Port path cost 4, Port priority 128, Port Identifier 128.3.
   Designated root has priority 32768, address c067.af00.12c6
   Designated bridge has priority 32768, address c067.af00.12c6
   Designated port id is 128.3, designated path cost 0
   Timers: message age 0, forward delay 0, hold 0
   Number of transitions to forwarding state: 1
   BPDU: sent 2350396, received 116

3560x-core1
IOS - 12.2(58r)SE1
модель WS-C3560X-48P-E

interface GigabitEthernet0/47
switchport trunk encapsulation dot1q
switchport mode trunk
end
!
interface GigabitEthernet0/48
switchport trunk encapsulation dot1q
switchport mode trunk
end

show spanning-tree vlan 30

VLAN0030
  Spanning tree enabled protocol rstp
  Root ID    Priority    32768
             Address     c067.af00.12c6
             Cost        8
             Port        48 (GigabitEthernet0/48)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32798  (priority 32768 sys-id-ext 30)
             Address     c08c.60f8.ac80
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/1               Desg FWD 4         128.1    P2p
Gi0/10              Desg FWD 4         128.10   P2p
Gi0/11              Desg FWD 4         128.11   P2p
Gi0/12              Desg FWD 4         128.12   P2p
Gi0/19              Desg FWD 19        128.19   P2p
Gi0/35              Desg FWD 4         128.35   P2p
Gi0/45              Desg FWD 4         128.45   P2p
Gi0/47              Desg FWD 4         128.47   P2p
Gi0/48              Root FWD 4         128.48   P2p

3560G-core2

IOS - 12.2(53)SE
Модель - WS-C3560G-48PS-S

interface GigabitEthernet0/52
switchport trunk encapsulation dot1q
switchport mode trunk
end

interface GigabitEthernet0/47
switchport trunk encapsulation dot1q
switchport mode trunk
end
show span vlan 30

VLAN0030
  Spanning tree enabled protocol rstp
  Root ID    Priority    32768
             Address     c067.af00.12c6
             Cost        4
             Port        47 (GigabitEthernet0/47)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32798  (priority 32768 sys-id-ext 30)
             Address     0024.50f4.d680
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/41              Desg FWD 4         128.41   P2p
Gi0/43              Desg FWD 4         128.43   P2p Peer(STP)
Gi0/45              Desg FWD 4         128.45   P2p
Gi0/46              Desg FWD 4         128.46   P2p
Gi0/47              Root FWD 4         128.47   P2p Peer(STP)
Gi0/48              Desg FWD 4         128.48   P2p
Gi0/51              Desg FWD 4         128.51   P2p
Gi0/52              Desg FWD 4         128.52   P2p