3Com CoreBuilder 7000, Operation Manual, Page: 86 / 264

86 C
HAPTER
4: P
RIVATE
N
ETWORK
-
TO
-N
ETWORK
I
NTERFACE
(PNNI) V
ERSION
1.0
parameters that the ATM network must have to be able to guarantee the
signal establishment. Call establishment consists of two operations:
Path selection
Connection setup at each point along the path
Path selection is made based on information stored in the topology
database and based on the QoS metrics that the network manager has
chosen. Once the path has been chosen, connections are made to each
node along the path. Each node confirms that the resources requested
are in fact available at the time of request. If for any reason there is no
confirmation, or the resources are not available the connection will
crankback and an alternate route will be chosen. This is explained in the
next section.
To utilize the advantages of source routing, as described above, PNNI uses
source routing for all connection setup requests. This implies that the first
node in the path (the source), selects the entire path to the destination.
The path is encoded as a
Designated Transit List
(DTL) which is explicitly
included in the connection setup request. The DTL specifies every node
used in transit across the peer group, and may optionally also specify the
logical links which are used between peer groups. If a node along the
path is unable to follow the DTL then the node must refuse that request
and must crankback the request to the node that created the DTL.
Configuring the
CoreBuilder 7000 for
PNNI
To configure the CoreBuilder 7000 for PNNI refer to the CoreBuilder
®
7000 Family ATM Switches Installation & Setup Guide.
Building a Hierarchy and Peer Groups with the CoreBuilder 7000
Software version 4.0 extended has the ability to participate in a hierarchy
with PNNI, but in order to build one, the Network Manager must use
E-IISP addressing between peer groups. Once the peer groups have been
made, static addresses must be used to establish links between the
groups.