我在 GNS3 中有一个拓扑，在 C1 和 C2 之间有一个 IPsec VPN 隧道（https://imgur.com/dnNkssU）。在客户端网络中，我配置了一个 CME 和一个软电话。当我打电话时质量很差。我使用 Startrinity 进行监控，结果就像这张照片https://imgur.com/UoRZyTs

为什么统计数据这么差？

C1 配置：

crypto isakmp policy 10
 encr 3des
 hash md5
 authentication pre-share
 group 2
crypto isakmp key parola123 address 8.8.11.2       
!
!
crypto ipsec transform-set myset esp-3des esp-md5-hmac 
 mode tunnel
!
!
!
crypto map mymap 1 ipsec-isakmp 
 set peer 8.8.11.2
 set security-association lifetime seconds 86400
 set transform-set myset 
 set pfs group2
 match address 100
!
!
!
!
!
!
interface FastEthernet0/0
 ip address 8.8.10.2 255.255.255.0
 ip nat outside
 ip virtual-reassembly in
 duplex half
 crypto map mymap
!
interface FastEthernet1/0
 ip address 10.1.1.1 255.255.255.0
 ip nat inside
 ip virtual-reassembly in
 duplex auto
 speed auto
!
!
ip nat inside source route-map nonat interface FastEthernet0/0 overload
ip route 0.0.0.0 0.0.0.0 8.8.10.1
!
access-list 100 permit ip 10.1.1.0 0.0.0.255 10.1.2.0 0.0.0.255
access-list 101 deny   ip 10.1.1.0 0.0.0.255 10.1.2.0 0.0.0.255
access-list 101 permit ip 10.1.1.0 0.0.0.255 any
no cdp log mismatch duplex
!
route-map nonat permit 10
 match ip address 101