3com TR User Manual

Page of 126
Port Configuration
4-7
identified by their VLAN ID. All ports are configured 
by default to VLAN 1.
1
Set this field by entering the desired VLAN number for 
the current port.
2
Press [Return].
Setting Port Personality 
Ports 1 through 4 on the Switch 2000 TR can be set 
to *Adapter* or *Hub*. In “adapter” mode, the port 
can connect to a token ring hub such as a SuperStack 
II Hub TR. In “hub” mode, the port acts like a hub 
port and can support a directly-connected worksta-
tion or server. Ports 5 through 12 support “adapter” 
mode only.
An external adapter cable can be used to directly 
attach workstations to ports 5 through12.
1
Set this field by toggling the [Space Bar] to your 
choice.
2
Press [Return].
Setting Port Priorities 
Switch 2000 TR has two fields for setting priority:
Internal Priority—The Internal Priority field allows 
you to distribute the available bandwidth among 
the ports. High-priority ports are given priority 
access to internal resources, taking priority over 
Normal priority ports. Settings are High or Normal.
Token Priority—The Token Priority field deter-
mines the priority of a token ring port on the 
Switch 2000 TR when transmitting to a segment.
For example: In Normal-priority a token level of 4 is 
reserved and all packets are transmitted with a token 
priority of 4 or higher, if necessary. In High-priority 
mode, a token level of 6 is reserved and all packets 
are transmitted with a token priority of 6 or higher, if 
necessary.
If Token Priority is disabled on a port, then packets are 
transmitted from that port with the priority token 
that is available at the time. Token Priority is turned 
off if disabled.
1
Set this field by toggling the [Space Bar].
2
Press [Return].
Setting Congestion Control
Congestion Control provides a method for determin-
ing how the Switch 2000 TR reacts in high-traffic load 
scenarios. Rather than discarding packets, this unique 
feature allows you to control the flow of traffic by 
assigning alternate methods for traffic handling. 
Choices:
Flow Control—Flow Control allows you to elimi-
nate frame loss by buffering excess frames at the 
end station where space is available until the 
Switch 2000 TR’s buffers are free. Once the buffers 
on the Switch 2000 TR are free, the end station’s 
buffers are emptied to the Switch 2000 TR and 
packet loss is eliminated.
Non-blocking—Non-blocking is the factory 
default state. In this mode frames are forwarded to 
available destination rings. This occurs even if a 
frame has been buffered due to a busy or down