3Com CoreBuilder 7000 Operation Manual page 79

In Figure 20, node A.1.2 will not transmit information about A.2.1,
because A.1.2 is in peer group A.1 and A.2.1 is in peer group A.2. After
all the PTSE information has been exchanged among all the members of
the peer group, the topology databases of each of the peer group
members are synchronized. See Table 20 for the complete topology
database for node A.1.2. You will notice that addresses for outside links
are not listed in the database.
Table 20 Topology Database for Node A.1.2 after PTSE Exchange
Node ID
A.1.2
A.1.1
A.1.3
The addresses in the topology database are saved and marked as native
addresses. Any address that leads the signal outside the PNNI domain is
considered to be a foreign address. In addition to the addresses of each
node in the peer group, the following information is also transmitted
with the PTSE and is also stored in the database:


Nodal Information — Node ID and capabilities. Peer Group Leader
Priority, as well as PNNI hierarchy information.


Topology State Information — Topology state parameters
(characteristics of the links, and characteristics of the nodes).


Reachability Information — Addresses and address prefixes which
describe the destinations to which calls may be routed. This
information is also for horizontal and outside links.
PTSE information is flooded on a continuous basis, until each node in the
peer group has the same information in its database. This is called
database synchronization. The mechanism used to send these messages
is called flooding. Flooding is an advertising mechanism in PNNI that
ensures that each node maintains an identical topology database.
Flooding is an ongoing activity. PTSEs are reissued whenever there is
change in the database. Figure 21 shows a sample of a topology
database log. For more explanation on PTSEs and topology databases,
see "Organizing a Network Hierarchy" on page 71 in the Management
Guide.
Description
Myself - I am a border node with groups A.3 and A.2
A member of my group
A member of my group
PNNI Routing 79