Configure LLC2 directory
Configuring
the time value of waiting for acknowledgement
Configuring
busy time value of remote end
Configuring
time value of Response
Configuring
the time of reject
Configuring
the size of window for resend
Configuring the size of accumulated data packet
Setting the acknowledgement time-delay
Setting the maximum numbers of acknowledgement
Debugging LLC2 link information
LLC2 (logic link control, class 2) protocol
is a network protocol providing connection acknowledgement and it is widely
applied to the local area network (LAN), especially to the network connection of
token ring of IBM communication system. Currently LLC2 only supports the
connection on the Ethernet.
The function provided by the command “LLC2” is to support the implementation of DLSW (Data Link Switch) protocol. The detail of DLSW can be referred to the related documents.
The command is used for controlling the frequency of query at the idle time (no data exchanged)
The command “no”
can be used for restoring to the default value.
llc2 idle-time
seconds
no llc2 idle-time
Seconds The interval seconds of sending RR frame at the idle time. The maximum is 60 seconds, the minimum is 1 second, and the default is 10 seconds.
Configuration mode: Interface Configuration
Notes: At idle time, no I (information) frame is exchanged and RR
(receive ready) frame is sent to the remote end periodically to tell the remote
end that the local end is ready to receive data. The relative small value should
be set for ensuring the prompt advice to the remote end. If the value is set too
small, too many RR frames is likely to be sent on the network.
Example: Setting RR frame sent every 12 seconds
int ethernet1/1
llc2 idle-time 12
Configuring the time value of waiting for acknowledgement
The command is used for controlling the waiting time of expecting remote
acknowledgement. The command “no” can be used for restoring to the default
value.
llc2 t1-time
seconds
no llc2 t1-time
Seconds The seconds of
waiting for remote acknowledgement. The maximum is 60 seconds, the minimum is 1
second and the default is 1 second.
Configuration mode: Interface configuration
Notes: When the local end sends I frame, it will wait for remote
acknowledgement. If no acknowledgement is received within a given time, the
I-frame will be resent. The relative big value should be set on the network
where the data is transmitted at a slow rate.
Example
Setting 12 seconds as the time value of waiting for acknowledgement.
int ethernet1/1
llc2 t1-time 12
Configuring busy time value of remote end
The command is used for controlling the waiting time when the remote end
is busy. The command “no” can be used for restoring to the default value.
llc2 tbusy-time
seconds
no llc2
tbusy-time
Seconds The waiting seconds when the remote end is busy. The maximum is 60 seconds, the minimum is 1 second and the default is 10 seconds.
Configuration
mode: Interface configuration
Notes:
a LLC2 connective end is able to inform the opposite end that local end is busy
and prevent the opposite end from sending data to local end by sending a RNR
(receive not ready) The relative big value can be set for averting the timeout.
Example: Setting 12
seconds as the busy time value of remote end.
int ethernet1/1
llc2 tbusy-time
12
Configuring time
value of Response
The command is used for controlling the time of waiting for the response of remote end. The command “no” can be used for restoring to the default value.
llc2 tpf-time
seconds
no llc2 tpf-time
Seconds The seconds of waiting for the response of remote end. The maximum is 60 seconds, the minimum is 1 second, and the default is 1 second.
Configuration Mode: Interface
Configuration
Notes: A LLC2 connective end sometimes needs
to know the status of opposite end. For this purpose, a command frame that
requires a response from the opposite end needs to be sent. When the opposite
end receives the command frame, it will reply a response frame. If the error
occurs in the process, the send end will keep waiting. In order to avoid the
situation, a clock needs to be enabled. When the arrival time is hit, the clock
will think that the error occurs and it will send a separate command frame. The
command is used for setting the time of waiting for the response of the opposite
end to the command frame.
Example:
Setting 12 seconds as the time of waiting for the response of the opposite end.
int ethernet1/1
llc2 tpf-time 12
Configuring the time of reject
The command is used for controlling the time of waiting for the response
of remote end to the reject frame. The command “no” can be used for
restoring to the default value.
llc2 trej-time
seconds
no llc2 trej-time
Seconds The seconds of waiting when the remote end is busy. The maximum is 60 seconds, the minimum is 1 second and the default is 3 seconds.
Configuration mode: Interface configuration
Notes: The data receive and send on the two ends of LLC2 link is carried out on the set sequence. When a LLC2 connective end receives I frame of opposite end whose sequence number is not the expected one, it will send a REJ (reject) frame and enable a clock. If no response is made at the arrival time, LLC2 link will be disconnected. The command is used for setting the time of waiting for the response of the opposite end to the REJ (reject) frame.
Example: Setting 12
seconds as the waiting time.
int ethernet1/1
llc2 trej-time 12
The command is used for controlling the times of re-sending the frame.
The command “no” can be used for restoring to the default value.
llc2 n2
retry-count
no llc2 n2
retry-count The times of resending frame. The maximum is 255, the minimum is 1 and the default is 8.
Configuration mode: Interface configuration
Notes: When one end of LLC2 sends the data
to the opposite end, it will wait for the acknowledgement of the opposite end.
If the opposite end does not send the acknowledgement within a given time, the
local end will resend the data. But the time of resend shall be limited. When
the value of resend times exceeds retry-count, LLC2 will be disconnected. The
command is used for setting the times of retry-count.
Example: Setting the times of re-send as 12
int ethernet1/1
llc2 n2 12
Configuring the size of window for resend
The command is used for controlling the maximum size of I frame send (namely the size of window for resend) when I frame is not confirmed. The command “no” can be used for restoring to the default value.
llc2 local-window
packet-count
no llc2
local-window
packet-count The maximum size of I frame send. The maximum is 127, the minimum is 1 and the default is 7.
Configuration
mode: Interface configuration
Notes: When one end of LLC2 link sends data to the opposite end, it can only send a certain amount of data before waiting for the acknowledgement of the opposite end. The command is used for setting the maximum value. When the set value is too big, it may lead to the loss of data because the opposite end is not able to receive all the data.
Example: Setting the size of send window as 12.
int ethernet1/1
llc2 local-window
12
Configuring
the size of accumulated data packet
The command is used for controlling the maximum local accumulated size of data packet when I frame (the remote end is busy) cannot be sent. The command “no” can be used for restoring to the default value.
llc2 holdqueue
packet-count
no llc2 holdqueue
packet-count The maximum size of data packets reserved by I frame when I frame is not confirmed.
Configuration
mode: Interface configuration
Notes:
When the opposite end is busy, one end of LLC2 link is not able to send data (I
frame). All the data shall be reserved before the busyness of the opposite end
is cleared. But the reserved amount is limited. The command is used for setting
the data amount to be reserved.
Example: Setting maximum data amount to be reserved as 120.
int ethernet1/1
llc2 holdqueue 120
Setting the acknowledgement time-delay
When an I-frame (information frame) is received, an acknowledgement frame shall be sent immediately. In order to reduce the unnecessary acknowledgement, the acknowledgement can be delayed. If information frame is sent, an information frame will be sent as an acknowledgement instead of acknowledge frame. When the information frame sent by the opposite end exceeds the acknowledged maximum size, an acknowledge frame will be sent immediately rather than at the timeout. The command below can be used for setting the value.
llc2 ack-delay-time seconds
Setting
the maximum numbers of acknowledgement
When the information frame sent by the opposite end exceeds the maximum number of acknowledgement in the process of acknowledging the time delay, the acknowledgement frame shall be sent immediately for clearing the network timeout perceived by the opposite end. The command below can be used for setting the value.
llc2 ack-max number
The command is used for showing the related information of LLC2 link connection
show llc interface
[type number]
type
Interface type
number Interface number
Configuration
Mode: Interface, configuration and global
Notes:
Showing the related information of LLC2 link connection. Under interface mode,
the command “show llc” is used for displaying LLC2 link information of the
interface.
Example:
Under interface mode, the command “show llc” is used for showing llc2
information on ethernet1/1.
int ethernet1/1
sho llc
ethernet1/1
Debugging LLC2 link information
The command is used for opening LLC2 debug switch
debug llc2
[packet][error][state]
Configuration
mode: Management Mode
Notes:
packet,Opening
the debug switch of LLC2 link status information
Example,
opening the debug switch of LLC2 link.
debug llc2 packet
debug llc2 state
debug llc2 error
The number of LLC2 frame received before the response can be configured. For example, it is supposed that two information frames are received at the time 0 rather than at the maximum number 3, the responses of these frames are not sent. If the third frame that makes the router response is not received within 800 ms, the response will be transmitted as the time-delay timer is activated.
interface interface e1/1
llc2 ack-max 3
llc2 ack-delay-time 800
In this connection, as it is told that all the frames are received, the counter that calculates the maximum number of information frame is reset as 0.