DDR设置步骤

1.设置静态路由

RouterA(config)#ip route 172.16.50.0 255.255.255.0 172.16.60.2

RouterA(config)#ip route 172.16.60.2 255.255.255.255 bri0

 

2.设置Interesting Traffic

804A(c onfig)#dialer-list 1 protocol ip permit

804A(config)#int bri0

804A(config-if)#dialer-group 1

 

3.配置Dialer信息

804A#config t

804A(config)#int bri0

804A(config-if)#ip address 172.16.60.1 255.255.255.0

804A(config-if)#no shut

804A(config-if)#encapsulation ppp

804A(config-if)#dialer-group 1

804A(config-if)#dialer-string 8350661

或者用804A(config-if)#dialer map ip 172.16.60.2 name 804B 8350661

代替dialer-string

 

sh run

804B#sh run

Building configuration...

Current configuration:

!

version 12.0

no service pad

service timestamps debug uptime

service timestamps log uptime

no service password-encryption

!

hostname 804B

!

ip subnet-zero

!

isdn switch-type basic-ni

!

interface Ethernet0

ip address 172.16.50.10 255.255.255.0

no ip directed-broadcast

!

interface BRI0

ip address 172.16.60.2 255.255.255.0

no ip directed-broadcast

encapsulation ppp

dialer idle-timeout 300

dialer string 8358661

dialer load-threshold 2 either

dialer-group 1

isdn switch-type basic-ni

isdn spid1 0835866201 8358662

isdn spid2 0835866401 8358664

hold-queue 75 in

!

ip classless

ip route 172.16.30.0 255.255.255.0 172.16.60.1

ip route 172.16.60.1 255.255.255.255 BRI0

!

dialer-list 1 protocol ip permit

!

可选参数

The dialer load-threshold command tells the BRI interface when to

bring up the second B channel. The option is from 1–255, where 255 tells the

BRI to bring up the second B channel only when the first channel is 100 percent

loaded. The second option for that command is in, out, or either. This

calculates the actual load on the interface on outbound traffic, inbound traffic,

or on the two combined. The default is outbound.

The dialer idle-timeout command specifies the number of seconds

before a call is disconnected after the last interesting traffic is sent. The

default is 120 seconds.

RouterA(config-if)#dialer load-threshold 125 either

RouterA(config-if)#dialer idle-timeout 180

The dialer load-threshold 125 tells the BRI interface to bring up the

second B channel if either the inbound or outbound traffic load is 50 percent.

The dialer idle-timeout 180 changes the default disconnect time from

120 to 180 seconds.

Multilink PPP (MP) allows load balancing between the two B channels in

a BRI. It is non-vendor specific, and provides packet fragmentation and reassembly,

sequencing, and load calculating. Cisco’s MP is based on RFC 1990.

The configuration would then look like this:

RouterA(config-if)#dialer load-threshold 125 either

RouterA(config-if)#dialer idle-timeout 180

RouterA(config-if)#ppp multilink

Not a tough configuration, but you want to use it nonetheless. This command

will fragment packets and send them over both lines, which provides

a load balancing effect of the data packet. You can verify the multilink is

working with the show ppp multilink command.

 

2个B信道

如果要同时激活2条B信道，可以使用

dialer load-threshold 1

也就是说把流量负载的值设到最小就可以了