ZyXEL Communications omni.net LCD+M Manuel D’Utilisation

 

7-6

The function of Bandwidth On Demand (BOD) will monitor the traffic on ISDN links while in 

Multilink PPP mode. If there is light traffic on the link, one of the channels will be dropped 

automatically. On the other hand, if only one B-channel is used and data traffic is high enough, 

BOD will establish the second B-channel to increase the bandwidth of the data link. 

The wait for the second B-channel carrier is 60 seconds. If the second B channel can not be 

connected successfully the BOD will try again after 60 seconds. If the second call is connected but 

negotiation failed, the omni.net will retry three times. If a connection is still not established after the 

third try, the Multilink PPP will be disabled automatically. 

For BOD, there are four parameters to set high/low threshold and persist time. Traffic utilization is 

measured in the ISDN link. Highly compressible data may not generate enough traffic to start the 

second B-channel. Both add-persist time and subtract-persist time must be set to activate BOD. 

Add traffic threshold for 'n' K bits per second. 'n' = 48 (default). 

Subtract traffic threshold for 'n' K bits per second. 'n' = 32 (default) 

Add persist time for 'n' period in 'm' unit, n = 0-127, m = s for seconds and m for 
minutes. 

Subtract persist time for 'n' period in 'm' unit, n = 0-127, m = s for seconds and m for 
minutes. 

Table 40. BOD AT Commands

Bandwidth Allocation Control Protocol (BACP) and Bandwidth Allocation Protocol (BAP) is used 

for call request and link drop under Multilink PPP.  

BACP is negotiated during the network phase. Without BACP/BAP, the directory numbers of both 

B-channels must be specified before dialing out. In some cases, it is not possible for the ISP to 

support more than one chassis that is capable of bundling both channels at the same time. With 

BACP/BAP, the second B-channel directory number can be obtained while requesting a call.