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T1 retransmit period, T2 wait ack period, T3 link al ive period – Cabletron Systems 1800 User Manual

Page 108: Logical dce, Low est/highest incomi ng channel, Low est/highest two-way channel, Low est/highest outgoi ng channel, Fl ow control negotiation, Throughput cl ass negotiation

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SmartSwitch 1800 4. 0 User G uide, Rev 01

T1 Retransmit Period

is the length of time before transmission of an I-frame if the previous transmission is
not acknowledged. If the period expires, the software will reset the timer and transmit
a supervisory frame demanding immediate acknowledgment. Also, the

Maximum

Retransmissions

(see that entry) counter will be incremented. The default value of

3000 ms

allows avoidance of unnecessary retransmission of frames that have merely

been delayed.

T2 Wait Ack Period

is the length of time the node will delay acknowledgment of a received I-frame if there
is no outgoing I-frame to be sent. If during this period the node receives an I-frame for
transmission, the acknowledgment will be sent with it, and the delay timer will be
reset.

T3 Link Alive Period

is the length of time after which the node will poll its counterpart if there is no data
transfer.

Logical DCE

defines the port as (if

Y

) logical DCE or (if

N

) DTE. The other end of the connection

must be the opposite of this port. Logical DCE/DTE is independent of physical. A
node connecting a subscriber device into a network should normally be configured as
logical DCE.

Lowest/Highest Incoming/Two-Way/Outgoing Channel

are the ranges of logical channel numbers (LCNs) that subscribers can use for calls
through this port. The valid values for each parameter are determined as follows:

Channel

Valid Values

Lowest Incoming

1

through

Highest Incoming

Highest Incoming

Greater than/equal to

Lowest Incoming

Lowest 2-Way

Greater than

Highest Incoming

Highest 2-Way

Greater than/equal to

Lowest 2-Way

Lowest Outgoing

Greater than

Highest 2-Way

Highest Outgoing

Lowest Outgoing

through

4095

Changing any parameter to a value that violates this order automatically changes any
other values now in violation, specifying the first value(s) within the valid range. If
any pair is not used, its constraints apply to the next higher or lower pair (whichever
is appropriate) in the above list.

Flow Control Negotiation

is an optional X.25 facility that permits negotiation of the flow control parameters
(packet and window sizes for either direction of data transmission) on a per call basis.
If

N

is selected, the default packet and window sizes will be used. If

Y

is selected, a

packet and/or window size included in a call packet will be used. (If either is not
included, the default for that parameter will be used.)

Throughput Class Negotiation

is an optional X.25 facility that permits negotiation of the throughput classes for either
direction of data transmission on a per call basis. If

N

is selected, the default (

Maximum

Throughput Class

) will be used. If

Y

is selected, any throughput class included in a call

packet will be used. (If a class for either direction is not included, its default value will
be used.)