Alcatel-Lucent 7750 SR OS, Interface Configuration Manual

Page: 107 / 444

Interface Configuration
7750 SR OS Interface Configuration Guide Page 107
Configuring Ports
This section provides the CLI syntax and examples to configure the following:
• Configuring Port Pool Parameters on page 107
• Configuring APS Parameters on page 110
• Configuring Ethernet Port Parameters on page 113
• Configuring SONET/SDH Port Parameters on page 115
• Configuring Channelized Ports on page 118
Configuring Port Pool Parameters
The buffer space is portioned out on a per port basis whether one or multiple MDAs share the
same buffer space. Each port gets an amount of buffering which is its fair-share based on the
port’s bandwidth compared to the overall active bandwidth.
IOM with each MDA has a dedicated buffer space: iom-20g; iom2-20g
IOM with multiple MDAs share a buffer space: iom-10g; iom3-xp
This mechanism takes the buffer space available and divides it into a portion for each port based
on the ports active bandwidth relative to the amount of active bandwidth for all ports associated
with the buffer space. The number of ports sharing the same buffer space depends on the type of
IOM the pools are being created on and the type of MDAs populated on the IOM. An active port is
considered to be any port that has an active queue associated. Once a queue is created for the port,
the system will allocate the appropriate amount of buffer space to the port. This process is
independently performed for both ingress and egress.
Normally, the amount of active bandwidth is considered as opposed to total potential bandwidth
for the port when determining the ports fair share. If a port is channelized and not all bandwidth is
allocated, only the bandwidth represented by the configured channels with queues configured is
counted towards the bandwidth represented by the port. Also, if a port may operate at variable
speeds (as in some Ethernet ports), only the current speed is considered. Based on the above, the
number of buffers managed by a port may change due to queue creation and deletion, channel
creation and deletion and port speed variance on the local port or other ports sharing the same
buffer space.
After the active bandwidth is calculated for the port, the result may be modified through the use of
the ‘ing-percentage-of-rate’ and ‘egr-percent-of-rate’ commands. The default value of each is
100% which allows the system to use all of the ports active bandwidth when deciding the relative
amount of buffer space to allocate to the port. When the value is explicitly modified, the active
bandwidth on the port is changed according to the specified percentage. If a value of 50% is given,