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ForeRunner
ATM Switch Network Configuration Manual
Configuring an Emulated LAN
The failure and recovery process occurs as follows:
1.
Eng LES/BUS 1 has lost power. All circuits connected to it are torn down. Low-
level signalling traffic (e.g., SSCOP messages) stop, and Switch 1 removes the
address of Eng LES/BUS 1 from its link tables.
2.
LECs 1 and 4 had been connected to Switch 1. They detect that their connections to
Eng LES/BUS 1 have been torn down; user intervention is not necessary.
3.
LECs 1 and 4 follow LANE 1.0 protocols to locate an LECS again to find the address
of their ELAN’s LES. In this example, they again connect to the LECS.
4.
The LECS reports to LECs 1 and 4 that their ELAN server is at ATM address N1.
This address is used by every peer LES supporting the ELAN; both Eng LES 1 and
Eng LES 2 in this example.
5.
LEC 1 sends a request to Switch 1 to establish a connection to address N1. Switch
1 no longer believes it has a direct connection to N1, and instead uses PNNI to
establish a circuit through Switches 2 and 3 to Eng LES 2.
6.
LEC 4 sends a request to Switch 2 to establish a connection to N1. Switch 2 may
have learned from Switch 1 that it no longer offers a connection to N1, or Switch 2
may attempt a route through Switch 1 and be “bounced back” through ATM
Forum PNNI crankback. Either way, Switch 2 finally routes the connection through
Switch 3 to Eng LES 2.
This recovery process occurs quickly -- clients typically recover at a rate of 100 clients per
minute -- and the result is a re-configured ELAN as shown in Figure 3.18.
Figure 3.18 -
ELAN Re-established Using the Second Server
Eng LEC 4
Eng LEC 5
Eng LEC 6 Eng LEC 7
Eng LEC 8
Eng LEC 9
Eng LEC 1
Eng LEC 2
Eng LEC 3
LES/BUS 1
Switch 1
Switch 3
Switch 2
LECS
ELAN A
LES/BUS 2
ELAN A
Summary of Contents for forerunner series
Page 6: ......
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 ...