Contemporary-control-systems Compact Managed Switches Software Manual for Web B Instrukcja Użytkownika Pobierz pdf (Strona 19)

TD020851-0MG

4.4.2 Configure Trunking

Port Trunking allows two or more ports to be grouped with the resulting group behaving

as a single logical link. A managed switch supports multiple trunks — each constructed

of 2 or more fixed physical ports.

To keep frames in order, packets with the same source/destination MAC addressing are

sent over the same trunk path — but the reverse path may follow a different link

because a hash algorithm is used to balance the load between links in a trunk.

Adding more ports (links) to a trunk group will increase the communication bandwidth

between two switches. Either one or two trunk groups can be defined — but always from

among ports 1–8. Even with a 16- or 24-port unit, only ports 1–8 support trunking.

Port Trunking on managed switches from Contemporary Controls also provides redundancy

with a fast recovery time (several milliseconds). If a link in the trunk group is lost, the

remaining links immediately take over and maintain communication between the switches.

Figure 14 illustrates three two-link trunks (A, B and C) connecting two computers

through four switches. This configuration could sustain a link loss in Trunk A, but within

milliseconds a redundant data path would be reconstructed between the two computers.

A similar recovery would manifest for a link lost in Trunk B or C. Indeed, even multiple

link losses — one in each trunk group — would not disrupt communication between the

two end stations except for the brief recovery time.

Figure 14 — Trunking

Figure 15 displays a sample Configure Trunking screen with two trunk groups defined.

The sample shows that only Group 1 is currently active. It would be permissible for

both of these two sample groups to be enabled simultaneously — but only because they

do not have any ports in common (overlapping ports).

Figure 15 — Configure Trunking

(copper ports only)

1 2 ... 14 15 16 17 18 19 20 21 22 23 24 ... 82 83

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Contemporary-control-systems Compact Managed Switches Software Manual for Web B Instrukcja Użytkownika Strona 19