IBM 8265 Nways ATM Switch, User Manual

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Configuring Summary Addresses
In PNNI, reachability is the advertising of end system addresses throughout a peer group for the purpose
of setting up connections between end systems. Reachability in PNNI routing is simplified by the
capability of having groups of addresses with a common prefix to be represented by that prefix. Such a
prefix is called a
summary address. PNNI generates a default summary address to provide reachability to
all end systems attached to the switch whose addresses share the switch's 13 byte ATM address prefix,
that is, whose addresses are generated by the ILMI address notification protocol. Additional non-default
summary addresses can be configured to provide reachability for address groups that do not share their
switch's 13 byte ATM address prefix. For example, entering:
à ð
8265ATM
>
set pnni node_ð summary_addr internal: 3ð 39.22.ee.99
á ñ
will cause all end systems directly attached to the switch via UNIs whose addresses begin with the first 30
bits of the string 39.22.ee.99 to be represented in the peer group by the just entered summary address.
PNNI stores a summary address without using it if no end system address prefixes match that address.
PNNI uses a longest matching prefix criterion, so no two summary addresses within a PNNI network
should have the same value unless they represent the same set of addresses. Furthermore, summary
addresses should be configured as long as possible to enhance longest matching prefix selection.
PNNI also supports path selection to end systems that lie outside a peer group, that is, end systems that
are connected to a peer group via non-PNNI links (typically IISP links). For example, at a switch belonging
to a peer group the command:
à ð
8265ATM
>
set pnni node_ð summary_addr exterior 28 45.22.ee.99
á ñ
then all end system addresses, reachable from that switch, that have a prefix the same as the first 28 bits
of the string 45.22.ee.99 and lie outside the peer group, will be represented in the peer group by the
entered summary address.
To ascertain the number of existing summary addresses, and the remaining number that can be set, enter
the following command:
à ð
8265ATM
>
show pnni summary_address
á ñ
The resulting display also includes an index number for each summary address set. This index number
can be used to delete a summary address, when used in the following command:
à ð
8265ATM
>
clear pnni summary_addr <n>
á ñ
where
<
n
>
is the index number displayed by the SHOW PNNI SUMMARY_ADDRESS command.
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IBM 8265: User's Guide