Summit24e3 Switch Installation and User Guide
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8
Forwarding Database (FDB)
This chapter describes the following topics:
•
Overview of the FDB on page 87
•
Configuring FDB Entries on page 88
•
Displaying FDB Entries on page 90
Overview of the FDB
The switch maintains a database of all media access control (MAC) addresses received on all of its ports.
It uses the information in this database to decide whether a frame should be forwarded or filtered.
FDB Contents
Each FDB entry consists of the MAC address of the device, an identifier for the port on which it was
received, and an identifier for the VLAN to which the device belongs. Frames destined for devices that
are not in the FDB are flooded to all members of the VLAN.
FDB Entry Types
The Summit24e3 supports up to 8,191 layer 2 FDB entries and 2,047 layer 3 FDB entries. The following
are four types of entries in the FDB:
• Dynamic entries
— Initially, all entries in the database are dynamic. Entries in the database are
removed (aged-out) if, after a period of time (aging time), the device has not transmitted. This
prevents the database from becoming full with obsolete entries by ensuring that when a device is
removed from the network, its entry is deleted from the database. Dynamic entries are deleted from
the database if the switch is reset or a power off/on cycle occurs. For more information about setting
the aging time, refer to “Configuring FDB Entries” later in this chapter.
• Nonaging entries
— If the aging time is set to zero, all aging entries in the database are defined as
static, nonaging entries. This means that they do not age, but they are still deleted if the switch is
reset.
• Permanent entries
— Permanent entries are retained in the database if the switch is reset or a power
off/on cycle occurs. The system administrator must make entries permanent. A permanent entry can
either be a unicast or multicast MAC address. All entries entered by way of the command-line
Summary of Contents for Summit Summit24
Page 12: ...12 Contents Summit24e3 Switch Installation and User Guide Index Index of Commands ...
Page 14: ...14 Figures Summit24e3 Switch Installation and User Guide ...
Page 24: ...24 Summit24e3 Switch Installation and User Guide Summit24e3 Switch Overview ...
Page 32: ...32 Summit24e3 Switch Installation and User Guide Switch Installation ...
Page 78: ...78 Summit24e3 Switch Installation and User Guide Configuring Ports on a Switch ...
Page 118: ...118 Summit24e3 Switch Installation and User Guide Network Address Translation NAT ...
Page 132: ...132 Summit24e3 Switch Installation and User Guide Ethernet Automatic Protection Switching ...
Page 146: ...146 Summit24e3 Switch Installation and User Guide Quality of Service QoS ...
Page 158: ...158 Summit24e3 Switch Installation and User Guide Status Monitoring and Statistics ...
Page 204: ...204 Summit24e3 Switch Installation and User Guide Interior Gateway Routing Protocols ...
Page 212: ...212 Summit24e3 Switch Installation and User Guide Safety Information ...
Page 216: ...216 Summit24e3 Switch Installation and User Guide Supported Standards ...
Page 238: ...238 Index Summit24e3 Switch Installation and User Guide ...
Page 244: ...244 Index of Commands Summit24e3 Switch Installation and User Guide ...