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ATM Switch Network Configuration Manual
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5.2.4 Peer Group Summary Node (PGSN)
A PGSN is a virtual (logical) or imaginary node that summarizes a peer group’s reachability
information. The PGSN has the peer group ID of its peer group as its switch summary prefix.
Each border switch in the peer group advertises a logical link (loglink) to the PGSN. The
PGSN is a logical representation of the switches contained in a peer group.
5.2.5 Backbone Topology
Loglinks between border switches and loglinks from border switches to PGSNs are called
backbone links and considered part of the backbone topology. Information regarding these
backbone links is propagated across peer group boundaries during database exchange and
flooding.
5.2.6 Single Switch Perspective
The main reason for grouping switches in large networks is to simplify each individual
switch’s view of the topology. For example, each switch in peer group A is aware of every
other switch in peer group A, the border switches in the rest of the network, the links between
them, and the backbone topology. Switches in peer group A are not aware, however, of the
internal topology of other peer groups. Instead, individual switches see a PGSN (see Figure
5.4).
Summary of Contents for forerunner series
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Page 16: ...TOC 10 ForeRunner ATM Switch Network Configuration Manual Table of Contents ...
Page 20: ...LOF 4 ForeRunner ATM Switch Network Configuration Manual List of Figures ...
Page 22: ...LOT 2 ForeRunner ATM Switch Network Configuration Manual List of Tables ...
Page 30: ...viii ForeRunner ATM Switch Network Configuration Manual Preface ...
Page 144: ...3 58 ForeRunner ATM Switch Network Configuration Manual Configuring an Emulated LAN ...
Page 180: ...6 12 ForeRunner ATM Switch Network Configuration Manual ATM Forum PNNI ...
Page 220: ...9 6 ForeRunner ATM Switch Network Configuration Manual Configuring Timing ...
Page 300: ...D 24 ForeRunner ATM Switch Network Configuration Manual Configuring FramePlus Modules ...
Page 308: ...Acronyms 8 ForeRunner ATM Switch Network Configuration Manual Acronyms ...
Page 346: ...Glossary 38 ForeRunner ATM Switch Network Configuration Manual Glossary ...
Page 352: ...Index 6 ForeRunner ATM Switch Network Configuration Manual Index ...