Nortel Networks 1000ASE-XD - Manual (Page 133)

Chapter 3 Using the console interface 133
Using the BayStack 420 10/100/1000 Switch
Choosing a high speed flow control mode
The high speed flow control feature allows you to control traffic and avoid
congestion on the Gigabit full-duplex link. If the receive port buffer becomes full,
the BayStack 420 Switch issues a flow-control signal to the device at the other end
of the link to suspend transmission. When the receive buffer is no longer full, the
switch issues a signal to resume the transmission. You can choose Symmetric or
Asymmetric flow control mode.
Symmetric mode
This mode allows both the GBIC port and its link partner to send flow control
pause frames to each other.
When a pause frame is received (by either the GBIC port or its link partner), the
port suspends transmission of frames for a number of slot times specified in the
control frame or until a pause-release control frame is received. Both devices on
the link must support this mode when it is selected.
Asymmetric mode
This mode allows the link partner to send flow control pause frames to the GBIC
port. When a pause frame is received, the receiving port suspends transmission of
frames for a number of slot times specified in the control frame or until a
pause-release control frame is received.
In this mode, the GBIC port is disabled from transmitting pause frames to its link
partner. Use this mode when the GBIC port is connected to a buffered repeater
device.
MultiLink Trunk Configuration Menu screen
The MultiLink Trunk Configuration Menu screen ( Figure 61 ) allows you to select
the appropriate screen to configure up to six MultiLink Trunks (you can group up
to four switch ports together to form each trunk).
You can configure up to six MultiLink Trunks in each stack, with trunk members
in either a single unit or distributed between units within the stack configuration
(distributed trunking).