Доброго времени суток!

Пытаюсь построить следующую схему: есть 2 роутера cisco 2921 (R1 и R2) с платами HWIC sw4e и два коммутатора  cisco me 3400 (SW1 и SW2). Все собрано в кольцо, на маршрутизаторах подняты по 2 вилана и HSRP.

Схема:

R1 ----- SW2
|           |
|           |
SW1------R2

За SW1 и SW2 два хоста в разных сетях и Vlan (VLAN 101 и VLAN99)
Кольцо в RVST, и если отключаю R1 - то все отлично, хосты и железо видит друг друга, но если отключаю R2, то пинг между хостами, а так же SW1 и SW2 пропадает.
Подскажите, куда копать. Схема вроде бы простая, и должна работать, но....
R1:
interface GigabitEthernet0/0
no ip address
ip virtual-reassembly in
duplex auto
speed auto
!
interface GigabitEthernet0/1
no ip address
duplex auto
speed auto
!
interface GigabitEthernet0/2
no ip address
duplex auto
speed auto
!
interface FastEthernet0/1/0
description LINK-FOR-SW1
switchport mode trunk
!
interface FastEthernet0/1/1
description LINK-FOR-SW2
switchport mode trunk
!
interface FastEthernet0/1/2
!
interface FastEthernet0/1/3
!
interface Vlan1
no ip address
shutdown
!
interface Vlan99
ip address 10.60.1.36 255.255.255.224
ip nat inside
ip virtual-reassembly in
standby 2 ip 10.60.1.33
standby 2 priority 105
standby 2 preempt
standby 2 name HSRP2
!
interface Vlan101
ip address 10.60.1.4 255.255.255.224
ip nat inside
ip virtual-reassembly in
standby 1 ip 10.60.1.1
standby 1 priority 110
standby 1 preempt
standby 1 name HSRP1
!

----------------------------------------
R2:

interface GigabitEthernet0/0
no ip address
duplex auto
speed auto
!
interface GigabitEthernet0/1
no ip address
duplex auto
speed auto
!
interface GigabitEthernet0/2
no ip address
shutdown
duplex auto
speed auto
!
interface FastEthernet0/1/0
description LINK-FOR-SW2
switchport mode trunk
!
interface FastEthernet0/1/1
description LINK-FOR-SW1
switchport mode trunk
!
interface FastEthernet0/1/2
!
interface FastEthernet0/1/3
!

interface Vlan1
no ip address
shutdown
!
interface Vlan99
ip address 10.60.1.37 255.255.255.224
ip nat inside
ip virtual-reassembly in
standby 2 ip 10.60.1.33
standby 2 priority 110
standby 2 preempt
standby 2 name HSRP2
!
interface Vlan101
ip address 10.60.1.5 255.255.255.224
ip nat inside
ip virtual-reassembly in
standby 1 ip 10.60.1.1
standby 1 priority 105
standby 1 preempt
standby 1 name HSRP1
!
!
-----------------------------------------------

SW1:

spanning-tree mode rapid-pvst
spanning-tree extend system-id
spanning-tree vlan 101 priority 24576
!
!
vlan internal allocation policy ascending
!
vlan 99,101
!
!
!
interface FastEthernet0/1
port-type nni
switchport access vlan 101
!

(кусь)

interface FastEthernet0/23
port-type nni
switchport mode trunk
!
interface FastEthernet0/24
port-type nni
switchport mode trunk
!
interface GigabitEthernet0/1
port-type eni
!
interface GigabitEthernet0/2
port-type nni
!
interface Vlan1
no ip address
no ip route-cache
shutdown
!
interface Vlan99
no ip address
no ip route-cache
!
interface Vlan101
description MANAGMENT
ip address 10.60.1.3 255.255.255.224
no ip route-cache
!
ip default-gateway 10.60.1.1
no ip http server
ip http secure-server
!
-------------------------------------------------

SW2:
spanning-tree vlan 99 priority 28672

vlan internal allocation policy ascending
!
vlan 99
name vlan99
!
vlan 101
name vlan101
!
!
!
interface FastEthernet0/1
port-type nni
switchport access vlan 99
!

(кусь)

interface FastEthernet0/23
port-type nni
switchport mode trunk
!
interface FastEthernet0/24
port-type nni
switchport mode trunk
!
interface GigabitEthernet0/1
port-type eni
!
interface GigabitEthernet0/2
port-type nni
!
interface Vlan1
no ip address
no ip route-cache
shutdown
!
interface Vlan99
description FOR-SW2
ip address 10.60.1.35 255.255.255.224
no ip route-cache
!
interface Vlan101
description FOR-SW1
no ip address
no ip route-cache
!
ip default-gateway 10.60.1.33
no ip http server
ip http secure-server

Подозреваю, что дело в PVST, до этого особо данную технологию не применял, возможно недокурил, подскажите как тогда при такой схеме ее донастроить?
Спасибо.