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154 Chapter 6: Using ISDN and DDR Technologies
As with BOD, the multiple links come up in response to a dialer load-threshold command.
The load can be calculated on inbound traffic or outbound traffic as needed for the traffic
between the specific sites. Multilink PPP provides bandwidth on demand and reduces
transmission latency across WAN links. Also, as in BOD, a router running MLPPP recalculates
the load every five minutes.
At any time, you can use a show interface command to see the current load of the interface.
Example 6-17 shows the configuration and the show interface BRI 0 command output.
The preceding show interface bri 0 1 command shows only the first B channel (hence the bri
0 1
). If the second B channel were up, the command show interface bri 0 2 could be entered
to view its status. Notice that as highlighted in Example 6-17, the load is currently 1/255. In
other words, little or no traffic is flowing across the link.
Example 6-17
Multilink PPP
RouterA(config)#interface BRI0
RouterA(config-if)#ip address 10.12.1.1 255.255.255.0
RouterA(config-if)#encapsulation ppp
RouterA(config-if)#ppp multilink
RouterA(config-if)#dialer idle-timeout 180
RouterA(config-if)#dialer load-threshold 110
RouterA(config-if)#dialer map ip 10.12.1.2 speed 56 2145552222
RouterA(config-if)#dialer map ip 10.12.1.2 speed 56 2145552223
RouterA(config-if)#dialer-group 1
!
RouterA(config)#dialer-list 1 protocol ip permit
!
RouterA(config)#ip route 10.13.1.0 255.255.255.0 10.12.1.2
RouterA(config)#end
!
RouterA#show interface bri 0 1
BRI0:1 is up, line protocol is up
Hardware is BRI with integrated NT1
MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec, rely 255/255, load 1/255
Encapsulation PPP, loopback not set, keepalive set (10 sec)
LCP Open, multilink Open
Open: IPCP
Last input 00:00:01, output 00:00:01, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
6148 packets input, 142342 bytes, 0 no buffer
Received 6148 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
6198 packets output, 148808 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
9 carrier transitions