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This chapter describes the parameters related to Logical Link Control, type 2 (LLC2) tunneling to and from Systems Network Architecture (SNA) networks. Table 79 lists the LLC2 Service parameters and commands.
Syntax
SHow [!<port> | !*] -LLC2 CONFiguration
No default
The CONFiguration parameter displays the current settings for LLC2 and tunneling. The display shows the LLC2 data link parameter settings, the tunnel interfaces configured, the tunnel media addresses configured, the tunnel virtual ring setting, and any current LLC2 settings.
Syntax
SETDefault !<port> -LLC2 CONTrol = ([Enable | Disable])
SHow [!<port> | !*] -LLC2 CONTrol
Disable
The CONTrol parameter defines the local LLC2 support, and specifies which port or ports on the bridge/router will serve as the LLC2 end system.
You can also configure this parameter for wide area ports if you need to enable the peer data exchange feature in an IBM Boundary Routing topology. For information on this feature, see the Configuring Boundary Routing System Architecture chapter in Using Enterprise OS Software.
Values
SETDefault -LLC2 FRCongestCont = ([Enable | Disable])
SHow -LLC2 FRCongestCont
Disable
The FRCongestCont parameter determines whether Frame Relay sends messages that the network is congested or uncongested to a port configured for LLC2. When Frame Relay congestion control is set for a NETBuilder bridge/router port, the network sends messages to the port when the network is congested and when the network becomes uncongested. These messages can lower the performance (response time) of SNA running on LLC2.
The messages are BECN=1 frames sent out by the Frame Relay network when it detects network congestion. Network congestion for a particular port is determined by the values entered when configuring Frame Relay congestion control for that port with the -FR CongestControl and -FR CIRBothDir parameters.
See Chapter 27 for more information on the -FR CIRBothDir and -FR CongestControl parameters. See the Configuring Wide Area Networking Using Frame Relay chapter in Using Enterprise OS Software for more information on Frame Relay congestion control and its effect on LLC2 and SNA.
Values
Syntax
SHow -LLC2 LlcLOG
No default
The LlcLOG parameter displays a log of LLC2 activity messages captured on the bridge/router and stored in a buffer. The display shows the most recent activity messages. Table 80 lists the event types captured in the log and the corresponding message that is displayed. In each message, hhhhhhhhhhhh represents a MAC address, xx represents a SAP nnn.nnn.nnn.nnn, which represents an IP address.
Syntax
SETDefault !<port> -LLC2 MaxFrame = <size>(128-4399)
SHow [!<port> | !*] -LLC2 MaxFrame
1,500
The MaxFrame parameter sets the maximum length of an information field. The value range is 128 to 4,399 bytes.
Syntax
SETDefault -LLC2 MaxTRaceData = <max_bytes_traced> (0-76)
SHow -LLC2 MaxTRaceData
16
The MaxTraceData parameter sets the maximum number of bytes of LLC2 data captured using the Trace facility. The value sets the number of bytes captured over and above the LLC2 address and control bytes. The number of bytes captured affects the types of data captured; the higher the value entered, the more detailed is the trace data that is captured. The number entered is rounded up to the nearest four; for example, if you enter the value as 29, the number is rounded up to 32.
Syntax
SETDefault !<port> -LLC2 ReceiveWindow = <size>(1-128)
SHow [!<port> | !*] -LLC2 ReceiveWindow
1
The ReceiveWindow parameter sets the receive window size of information frames. The value range is 1 to 128.
Syntax
SETDefault !<port> -LLC2 RetryCount = <retrys>(1-255)
SHow [!<port> | !*] -LLC2 RetryCount
7
The RetryCount parameter defines the maximum number of times to retransmit after expiration of the reply timer. The value range is 1 to 255.
Syntax
SHow -LLC2 SESSions
No default
The SESSions parameter displays any current LLC2 sessions, including any active remote LLC2 sessions. This parameter only displays sessions at the LLC2 level.
Syntax
SETDefault !<port> -LLC2 TImerAck = <milliseconds>(0-500)
SHow [!<port> | !*] -LLC2 TImerAck
0 milliseconds
The TImerAck parameter is used as the acknowledge timer and specifies the amount of time the bridge/router waits before acknowledging the received information frame. This is a link performance parameter. The connection is considered stopped after retrying the RetryCount.
The timer range is 0 to 500 milliseconds.
Syntax
SETDefault !<port> -LLC2 TImerInact = <milliseconds>(3000-180000)
SHow [!<port> | !*] -LLC2 TImerInact
60,000 milliseconds
The TImerInact parameter defines the time the bridge/router waits to receive a frame from the other end before disconnecting a session. Make sure the TImerInact value entered is at least five times the value entered for the TImerReply parameter.
The timer range is 3,000 to 180,000 milliseconds.
Syntax
SETDefault !<port> -LLC2 TImerReply = <milliseconds>(500-60000)
SHow [!<port> | !*] -LLC2 TImerReply
3,000 milliseconds
The TImerReply parameter sets the reply timer value. This is the length of time the bridge/router waits for a response to a command frame or for an acknowledgment of an information frame. After this timer expires, the bridge/router retransmits the command for a number of times specified in the RetryCount parameter. If this is still unsuccessful, the link is stopped.
The timer range is 500 to 60,000 milliseconds.
SHow -LLC2 TRaceData
No default
The TRaceData parameter displays all LLC2 entries in the trace buffer.
Syntax
SETDefault !<port> -LLC2 TransmitWindow = <size>(1-128)
SHow [!<port> | !*] -LLC2 TransmitWindow
7
The TransmitWindow parameter sets the retransmit window size of information frames. The value range is 1 to 128.
Syntax
SETDefault -LLC2 TUNnelPRiority = <H | M | L | DEFault>
SHow -LLC2 TUNnelPRiority
DEFault
The TUNnelPRiority parameter assigns a priority to an LLC2 packet that is tunneled over an Internet protocol (IP) internetwork. Possible priorities include high, medium, or low. If this parameter is set to default, the system uses the -IP QueuePriority setting. For more information on -IP DefaultPriority, see IP Service Parameters. For more information on data prioritization, see the Prioritizing Multiprotocol Data chapter in Using Enterprise OS Software.
The priority of LLC2 tunnel packets is maintained across 3Com bridge/routers through the use of the type of service (TOS) field in the IP header.
You can also display the setting of this parameter with the SHow command.
Syntax
SETDefault -LLC2 TUNnelVRing = <Number>(1-4095)
SHow -LLC2 TUNnelVRing
92 (decimal)
The TUNnelVRing parameter sets the virtual ring number for the Internet. This allows token ring networks on both ends of the tunnel to interpret the Internet as an intermediate token ring network. The virtual ring number must be configured on the peer bridge/routers at both ends of the tunnel.
The value range is 1 to 254.