Avaya M770 ATM Switch User’s Guide 123

Chapter 10

Managing PNNI Routing
This chapter describes how to use the command-line interface to manage the PNNI
routing in an Avaya M770 ATM Switch. For information about how to access and
use the Avaya M770 ATM Switch command-line interface, see Chapter 3 How to
Use the Command-line Interface.

PNNI (Private Network-Network Interface)

The description in this chapter assumes basic knowledge of the PNNI protocol. For
more information regarding the PNNI standard, refer to the ATM Forum
publication (af-pnni-0055.000).
Hierarchical PNNI
Hierarchical PNNI is supported from M770 ATM Switch Embedded S/W Version
2.1 and above. You can now configure your ATM network into a hierarchy of peer
groups, with multiple peer groups at each level. A single M770 ATM Switch can
operate as both a physical and a logical node. There may be up to four logical nodes
in four heirarchy levels in the same switch. The physical node represents the switch
itself, while a logical node in a higher level peer group represents a lower level peer
group.
In the following sections describing PNNI, the 'level' parameter in a command
refers to the instance of the PNNI node within the switch, level = 1 is the physical
node, and level = 2 is the first logical node.
PNNI Implementation in the Avaya M770 ATM Switch
The architecture of the M770 ATM Switch is a distributed one, i.e. no single point of
failure. All cards implement full PNNI, and at the same time share the information
received and produced by each other. Information generated by an individual card
is shared by all other cards and accepted as if it is self-originated. All switch cards
share the same node ID and peer group ID, so to other switches in the peer group it
looks like one unified switch.
When Hierarchical PNNI configurtion is used, the Master Agent module of the
Avaya M770 ATM switch (the PDC or PNNI Designated Card) has a special role.
This is the module that advertises the switch as willing to become a PGL (Peer
Group Leader). If it is elected as PGL, the next higher level node the LGN (Logical
Group Node) resides in the PDC module. Therefore, commands that are applicable
only PGL or LGN can be performed only on the PDC.