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Chapter 3. Ethernet switch interoperability 27
3.3 Basic Ethernet interoperability exercises
In the following sections we describe our experiences during two test
scenarios, and we show the configuration process in detail. The two
scenarios are:
1. Port trunking or EtherChannel interoperability
2. IEEE 802.1Q VLAN interoperability
We were left with the general impression that interoperability between the
IBM and Cisco switches we sampled worked very well, in fact over
expectation. In Chapter 2, “Functional comparisons” on page 7 we discussed
how two proprietary protocols, port trunking and EtherChannel, can
interoperate.
It also seemed as if an internal improvement made by Cisco Systems to the
spanning tree protocol worked even when the Cisco switch was connected to
an IBM switch. The benefit was that STP reconfiguration only took a few
seconds. However, we did not investigate this in detail.
3.3.1 Lab 1: Trunking IBM 8275-322 and Cisco 2924-XL
3.3.1.1 Setup for Lab 1
In this test we will connect two Ethernet switches via a trunk (EtherChannel).
Figure 6. Lab 1, connections
Figure 6 shows the physical connections for this test. All ports on the two
switches will be in the same VLAN, VLAN 1 (the default VLAN), and the two
switches will be interconnected via a trunk of two FastEthernet connections,
IBM8275-322
Lab1
Cisco 2924XL
VLAN 1 VLAN 1
Trunk 1
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