Avaya ESS User Manual page 29

Because the IPSIs in Port Networks 1 through 4 cannot communicate with the Main server or
the S8700 ESS server, they adjust their priority list and move the S8500 ESS server to the top
of the list. The no service timer activates for Port Networks 1 through 4. When the no service
timer expires, the IPSIs in Port Networks 1 through 4 request service from the S8500 ESS
server. The S8500 ESS server acknowledges the request and assumes control of Port Network
1 through 4 (see Figure
outage from the failure.
Figure 5: Network failure - ESS recovery
S8500 ESS Server
(2nd Alternative)
disc
PN #1
PN #2
Port Network Control Link (EAL)
IP Connection into Control Network
Server or Network Failure
VoIP Path
DSIC LInk
cycmerf2 KLC 031505
5). Note that Port Networks 5 through 8 did not experience any service
S8710 Media Server
(Main Server)
PN #4
PN #3
CSS / EI (Fiber)
ATM / ATM-EI (Fiber)
Dup Link
Out of Service
disc COMPACT
1
2
UID
disc
COMPACT
1
2 S8700 ESS Server
UID
(1st Alternative)
PN #5
PN #6
Issue 1.1 June 2005
ESS failover examples
PN #8
PN #7
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