H3C Technologies H3C S12500 Series Switches - Manual (Page 189)

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Configuring the size of shared buffers on an
interface card
An interface card uses a buffer with a fixed size to buffer the packets received and sent. A buffer
comprises multiple storage units. It is divided into two areas: fixed buffer and shared buffer. The fixed
buffer is allocated to the interfaces according to a certain algorithm, and the shared buffer is shared by
all interfaces. When the traffic of an interface becomes heavy, and the fixed buffer cannot provide
sufficient memory, the shared buffer provides temporary memory for the interface.
By default, the fixed buffer and the shared buffer contain a fixed number of storage units. You can
configure the number of storage units in the shared buffer as needed. Because the total number of
storage units in a buffer is fixed, the number of storage units in the fixed buffer will change after your
configuration. You can tune the shared buffer area depending on traffic patterns. If transient large traffic
bursts occur on some interfaces, you can expand the shared buffer to accommodate the bursts to prevent
traffic loss. If transient small traffic bursts often occur on the interfaces, you can decrease the shared
buffer so that each port can get more dedicated buffer memory.
To set the size in blocks of the receive or transmit buffer shared by all interfaces on an interface card:
Step Command Remarks
1. Enter system view. system-view N/A
2. Set the size in blocks of the
receive or transmit buffer
shared by all interfaces on an
interface card.
• In standalone mode:
buffer-manage { ingress |
egress } slot slot-number
share-size size-value
• In IRF mode:
buffer-manage { ingress |
egress } chassis chassis-number
slot slot-number share-size
size-value
Optional.
Use either command.
By default, the size in blocks of the
shared receive buffer is 1024, and
that of the shared transmit buffer is
4096.
Only the LST1XP16LEC1,
LST1XP16LEC2, and
LST1XP16LEB1 cards support the
ingress keyword. That is, you can
modify the size of the shared
receive buffer for these cards.
Clearing unused 16-bit interface indexes
The device must maintain persistent 16-bit interface indexes and keep one interface index match one
interface name for network management. After deleting a logical interface, the device retains its 16-bit
interface index so the same index can be assigned to the interface at interface re-creation.
To avoid index depletion causing interface creation failures, you can clear all 16-bit indexes that have
been assigned but not in use. The operation does not affect the interface indexes of the interfaces that
have been created but the indexes assigned to re-recreated interfaces might change.
A confirmation is required when you execute this command. If you fail to make a confirmation within 30
seconds or enter N to cancel the operation, the command is executed.
To clear unused 16-bit interface indexes: