X.25, Hosta hostb – Verilink 9000 Series (34-00271) Product Manual User Manual

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HAPTER

13: X.25

The second situation (see Figure 13-7) is when two devices with the same address
generate internal connect requests to the X.25 port. Normally, the MultiPro unit
places a call request on behalf of the first station and refuses the internal connect
request from the second device. If pooling is turned on, though, the MultiPro unit
searches through the channel list for an entry with the same subaddress. If a match
is found and that entry is not connected, the MultiPro unit places a call request for
the second station.

This option is handy for remote sites that have duplicate station addresses on
separate terminal ports with different default hosts that need to use a common
transport path to reach their destinations.

DOWNLOAD CONFIG

MODE BACKUP

NET

ALARM POWER

PRISM 9111

T

R

A

N

S

P

O

R

T

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Processor

DOWNLOAD CONFIG

MODE BACKUP

NET

ALARM POWER

PRISM 9111

T

R

A

N

S

P

O

R

T

®

X.25

Terminal 01
Default host = HOSTA

Terminal 01
Default host = HOSTB

Unit 001

Unit 002

Call Request: sub-addr = 001

Internal connect request

addr = 01 dest. = HOSTA

Internal connect request

addr = 01 dest. = HOSTB

Call req. sub-addr. = 001

dest. = HOSTA / addr. = 01

Call req. sub-addr. = 001

dest. = HOSTB / addr. = 01

Unit 001

Channel List

Addr

Sub-addr

01

02

03

01

001

002

003

001

Call Request: sub-addr = 001

HOSTA

HOSTB

Figure 13-17 Typical Application with the Address Pooling Option - Scenario 2

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