User's Manual

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Users Manual of CS-6306R
5.2.17 Controlling the Size of Cache
The size of cache can be controlled. The cache is used for storing the data that is not decided to be sent to
remote SDLC station. The command is especially useful in SDLC protocol convert equipment that implements
the communication between SNA workstation whose link layer protocol is LLC2 in token-ring local area
network (LAN) and SNA workstation whose link layer protocol is SDLC on serial link. The frame length and the
size of window on the token-ring are usually much bigger than the acceptable ones on the serial link. What’s
more, the serial link is slower than token-ring.
In order to control the accumulation problem produced in the high-speed data transmission from token-ring to
serial link, the command below can be used on the basis of each address under interface configuration mode:
Command Purpose
sdlc holdqueue address
queue-size
Setting the maximum quantity of the data
packets stored in the sequence before
transmission.
5.2.18 Controlling the polling of slave station
The interval of router’s polling to the slave station, the length of time of sending data from master station to
slave station and how long the software polls a slave station before moving to the next station can be
controlled.
The following points should be noted in using these commands:
Only when the slave station is polled by the master station, the data can be transmitted. When the polling
terminates and the value of timer is too big, the response time of slave station will add. When the value of the
timer is reduced too small, it will lead to the congestion of serial link and data flood due to the excessive and
unnecessary polling frames sent from the slave station, which takes the extra CPU time for dealing with them.
The communication efficiency between master station and single slave station can be improved by increasing
the limit value of polling, but it may delay the polling to other slave stations.
One or more commands below can be used under interface configuration mode for controlling the polling of
slave station:
Command Purpose
sdlc poll-pause-timer milliseconds
Configuring the waiting time interval of router’s
polling to two slave stations on some single
serial port.
sdlc poll-limit-value count
Configuring the times of a master station’s
polling to slave station.
The “def” format of these commands can be used for restoring to the default polling value.