问答题

以下是使用E1线路实现多个64Kbit/s专线连接。
当链路为T1时，channel-group编号为0～23，Timeslot范围为1～24；当链路为E1时， channel-group编号为0～30，Timeslot范围为1～31。
路由器具体设置如下：
Current configuration:
version 11.2
no service udp-small-servers
no service tcp-small-servers
!
hostname router1
!
enable secret 5 $ 1 $ XN08 $ Ttr8nfLoP9.2RgZhcBzkk/
enable password cisco
!
!
ip subnet-zero
controller E1 0
framing NO-CRC4
channel-group 0 timeslots 1
channel-group 1 timeslots 2
channel-group 2 timeslots 3
!
interface Ethernet0
ip address 133.118.40.1 255.255.0.0
media-type 10BaseT
interface Ethernet1
no ip address
shutdown
interface Serial0:0
ip address 202.119.96.1 255.255.255.252
encapsulation hdlc
no ip mroute-Cache
interface Serial0:1
ip address 202.119.96.5 255.255.255.252
encapsulation hdlc
no ip mroute-Cache
!
interface Serial0:2
ip address 202.119.96.9 255.255.255.252
encapsulation hdlc
no ip mroute-Cache
no ip classless
ip route 133.210.40.0 255.255.255.0 Serial0:0
ip route 133.210.41.0 255.255.255.0 Serial0:1
ip route 133.210.42.0 255.255.255.0 Serial0:2
line con 0
line aux 0
line vty 0 4
password cicso
Iogin
!
end

解释配置中画线部分内容含义。