Verilink 9000 Series (34-00271) Product Manual - Manual (Page 263)

X.25 Channel List 241
A third use for pooling is when no subaddressing is necessary as connections are
established between MultiPro units. If no entry is made in the sub-address field of
the channel list, the field is not blank but is a null. In the MultiPro network a null
is a valid subaddress. To alleviate the need to assign unique subaddresses to each
entry in the channel list, the field may be left blank and the pooling option turned
on for each entry.
When an X.25 port configured in this manner receives a call request, it considers
the subaddress to be a null and searches for a matching entry in the channel list.
Since each entry in the channel list contains null as the subaddress and has pooling
set, the call request is assigned to the next entry in the channel list regardless of
the related address. When X.25 generates the internal connect request, though, the
terminal address is taken from the user data field of the call request and not from
the channel list. This ensures address integrity all the way to the final destination.
Figure 13-18 and Figure 13-19 illustrate how this is done.
DOWNLOAD CONFIG
MODE BACKUP NET ALARM POWER
PRISM 9111
T R A N S P O R T
®
Processor
DOWNLOAD CONFIG
MODE BACKUP NET ALARM POWER
PRISM 9111
T R A N S P O R T
®
X.25
Terminal 01
Terminal 02
HOSTA 01 & 02
Figure 13-18 Typical Application with the Address Pooling Option - Scenario 3