三台路由器通过PCM线路互连，实现三个局域网之间的通信。

 

router a ----------PDH/SDH----------router b

                          |---------router c

 

总部采用3725路由器，配置NM-1CE1U模块，通过2M线路接入传输网，从而和各分支机构互联；B、C采用cisco2621XM,配置WIC-1T串口卡，各申请128K线路接入传输网。

 

 

 

//router a

int fa0/0

  no shut

  description connected to lan-a

  ip addr 192.168.10.254 255.255.255.0

  keepalive 10

 

controller e1 1/0

 

  framing no-crc4   //配置CE1/PRI接口的帧校验格式，不进行帧校验为 no-crc4，采用4字节CRC校验为crc4，具体采用哪种格式请咨询线路供应商。

 

  channel-group 0 timeslot 1-2

  channel-group 1 timeslot 3-4  //进行时隙的划分，这里将1、2时隙捆绑为0组，3、4时隙捆绑为1组，0和1组分别对应下面的虚拟串口serial1/0:0和serial1/0:1

 

int s1/0:0

  description connected to router b

  encap ppp

  ip addr 192.168.1.1 255.255.255.252

 

int s1/0:1

  description connected to router c

  ip addr 192.168.1.5 255.255.255.252

 

ip route 192.168.11.0 255.255.255.0 serial1/0:1

ip route 192.168.12.0 255.255.255.0 serial1/0:2

 

 

 

//router b

int fa0/0

  description connected to lan b

  ip addr 192.168.11.254 255.255.255.0

  keepalive 10

 

int s0/0

  description connected to router a s1/0:0

  encap ppp

  ip addr 192.168.1.2 255.255.255.252

 

ip route 0.0.0.0 0.0.0.0 serial 0/0 1

 

 

//router c

int fa0/0

  description connected to lan c

  ip addr 192.168.12.254 255.255.255.0

  keepalive 10

 

int s0/0

  description connected to router a s1/0:1

  encap ppp

  ip addr 192.168.1.6 255.255.255.252

 

ip route 0.0.0.0 0.0.0.0 serial 0/0 1