Имеются две циски, между которыми поднят L2L VPN. Обе подключены по оптике 100Mbps.
Конфигурация следующая:
RouterA
Cisco 2821 (12.3(8r)T7)

!        
crypto isakmp policy 1
hash md5
authentication pre-share
group 2  
crypto isakmp key VPNaccess address 212.112.103.131 no-xauth
!
crypto ipsec transform-set MySet esp-des esp-md5-hmac
!
crypto map mymap 10 ipsec-isakmp
set peer 212.112.103.131
set ip access-group RouterB_ACL out
set transform-set MySet
match address RouterB
!
...
!        
interface FastEthernet0/1/1
switchport access vlan 12
no ip address
no cdp enable
!        
interface Vlan12
description INTERNET
ip address 212.112.102.146 255.255.255.252
ip access-group 106 in
ip nat outside
ip tcp adjust-mss 1300
crypto map mymap
!

----------------
RouterB
Cisco 1760 (12.2(7r)XM2)

!        
crypto isakmp policy 1
hash md5
authentication pre-share
group 2  
crypto isakmp key VPNaccess address 212.112.102.146 no-xauth
!        
!        
crypto ipsec transform-set MySet esp-des esp-md5-hmac
!        
crypto map mymap 10 ipsec-isakmp
set peer 212.112.102.146
set ip access-group RouterA_ACL out
set transform-set MySet
match address RouterA
!        
interface FastEthernet0/4
switchport access vlan 2
no ip address
no cdp enable
!  
interface Vlan2
ip address 212.112.103.131 255.255.255.248
ip access-group 106 in
ip tcp adjust-mss 1300
crypto map mymap
!

В итоге, канал поднимается, все ок, но при этом скорость никакая. файл 4Мб качает 1-2 минуты. При этом на тех же каналах без VPN все летает. Пробовал менять mtu, не помогает.
На RouterB много ошибок отсылки:

interface: Vlan2
    Crypto map tag: mymap, local addr 212.112.103.131

   protected vrf: (none)
   local  ident (addr/mask/prot/port): (192.168.31.0/255.255.255.0/0/0)
   remote ident (addr/mask/prot/port): (192.168.11.0/255.255.255.0/0/0)
   current_peer 212.112.102.146 port 500
     PERMIT, flags={origin_is_acl,}
    #pkts encaps: 946829, #pkts encrypt: 946829, #pkts digest: 946829
    #pkts decaps: 118316, #pkts decrypt: 118316, #pkts verify: 118316
    #pkts compressed: 0, #pkts decompressed: 0
    #pkts not compressed: 0, #pkts compr. failed: 0
    #pkts not decompressed: 0, #pkts decompress failed: 0
    #send errors 1268, #recv errors 0

     local crypto endpt.: 212.112.103.131, remote crypto endpt.: 212.112.102.146
     path mtu 1500, ip mtu 1500
     current outbound spi: 0xCF7C6C28(3481037864)

     inbound esp sas:
      spi: 0x662AA67B(1714071163)
        transform: esp-des esp-md5-hmac ,
        in use settings ={Tunnel, }
        conn id: 2005, flow_id: C1700_EM:5, crypto map: mymap
        sa timing: remaining key lifetime (k/sec): (4587963/1392)
        IV size: 8 bytes
        replay detection support: Y
        Status: ACTIVE

     inbound ah sas:

     inbound pcp sas:

     outbound esp sas:
      spi: 0xCF7C6C28(3481037864)
        transform: esp-des esp-md5-hmac ,
        in use settings ={Tunnel, }
        conn id: 2006, flow_id: C1700_EM:6, crypto map: mymap
        sa timing: remaining key lifetime (k/sec): (4580869/1392)
        IV size: 8 bytes
        replay detection support: Y
        Status: ACTIVE

     outbound ah sas:

     outbound pcp sas:

Куда копать???