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GarrettCom DS8016 User Manual

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Magnum DS8016 Dual-Speed Stackable Hubs Installation and User Guide (07/06)

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.

Bridge
Module

10 BUS

100

10 Mbps Domain

100 Mbps Traffic

10Mb Domain : 10Mbps packets
forwarded when the destination addresse
NOT

are

is

in the 10Mb domain address table.

100Mbps Domain :

100Mbps packets are

forwarded when the destination address is
NOT in the 100Mb domain address table.

10Mbps Domain :

10Mbps packets are

filtered when the destination address is

in the 10Mbps domain address table.

100Mbps Domain :

100Mbps packets are

filtered when the destination address is

in the 100Mbps domain address table.

10 Mbps Traffic

100 Mbps Domain

Fig 4.1 Filtering vs Forwarding in Domain Switched Hubs with an internal

Bridge or Switch

1.

Filter / Forward logic for both 10Mb and 100Mb domains

Packet

Source

Destination

Address Table

Filter/Forward

Source Address Address Maintenance Action
10 Mb

Not in table

Not in table

Add source to table

Forward

10 Mb

Not in table

In table

Add source to table

Filter

10 Mb

In table

Not in table

None

Forward

10 Mb

In table

In table

None

Filter

100 Mb

Not in table

Not in table

Add source to table

Forward

100 Mb

Not in table

In table

Add source to table

Filter

100 Mb

In table

Not in table

None

Forward

100 Mb

In table

In table

None

Filter

Table 4.1: DS8016-B Domain-Switched Hub Functionality

2.

Address Learning (Address Table Maintenance)

The Magnum DS8016-B bridge module is a state machine design which has a

total address table capacity of 8K addresses. With a large address table, a Magnum DS8016

can serve the needs of a medium-sized to large network. Table 4.1 shows what filter /

forward action the Magnum DS8016-B will take in each packet-processing situation, and

when a new node address will be added to the internal Address Table. When a new node-

address packet comes into a port for the first time, then the new source address is “learned”

at the same time that the packet is forwarded. After learning, subsequent packets from the

same node address are routinely processed. The address tables are flushed periodically to

update the network status and to purge any inactive stations from the tables of both domains.

3. Throughput Increase