Xin các huynh chỉ giáo giúp em với???

[phamhaanh]

Xin các huynh giải thích những dòng lệnh màu đỏ giúp em với ???

! This line enables Cisco Express Forwarding (CEF)
ip cef
!
ip sla monitor 1
type echo protocol ipIcmpEcho 10.0.0.100 source-interface FastEthernet0/0
! IP address 10.0.0.100 is primary DNS of ISP_1
timeout 1000
threshold 250
frequency 30
ip sla monitor schedule 1 life forever start-time now
ip sla monitor 2
type echo protocol ipIcmpEcho 10.0.0.101 source-interface FastEthernet0/0
! IP address 10.0.0.101 is secondary DNS of ISP_1
timeout 1000
threshold 250
frequency 30
ip sla monitor schedule 2 life forever start-time now
!
!
ip sla monitor 3
type echo protocol ipIcmpEcho 20.0.0.100 source-interface FastEthernet0/1
! IP address 20.0.0.100 is primary DNS of ISP_2
timeout 1000
threshold 250
frequency 30
ip sla monitor schedule 3 life forever start-time now
ip sla monitor 4
type echo protocol ipIcmpEcho 20.0.0.101 source-interface FastEthernet0/1
! IP address 20.0.0.101 is primary DNS of ISP_2
timeout 1000
threshold 250
frequency 30
ip sla monitor schedule 4 life forever start-time now
!
!
track 1 rtr 1 reachability
track 2 rtr 2 reachability
track 3 rtr 3 reachability
track 4 rtr 4 reachability
!
! Tracker for ISP_1
track 10 list boolean or
object 1
object 2
!
! Tracker for ISP_2
track 20 list boolean or
object 3
object 4
!
! Interface connected to ISP_1
interface FastEthernet0/0
ip address 10.0.0.2 255.255.255.0
ip load-sharing per-packet
duplex auto
speed auto
!
! Interface connected to ISP_2
interface FastEthernet0/1
ip address 20.0.0.2 255.255.255.0
ip load-sharing per-packet
duplex auto
speed auto
!
! Interface connected to LAN
interface FastEthernet1/0
ip address 192.168.100.2 255.255.255.0
ip load-sharing per-packet
duplex auto
speed auto
!
! Two equal cost static routes to ISP_1 and ISP_2
ip route 0.0.0.0 0.0.0.0 10.0.0.1 track 10
ip route 0.0.0.0 0.0.0.0 20.0.0.1 track 20
!