Cisco Certified Network Associate (CCNA) Practice Exam

What parameter can vary on ports within an EtherChannel?

1. Channel group number

2. IP address

3. DTP negotiation settings

4. Speed and duplex

The correct answer is: DTP negotiation settings

In an EtherChannel configuration, the DTP (Dynamic Trunking Protocol) negotiation settings are the parameters that can vary across the member ports. EtherChannel is designed to aggregate multiple physical links into a single logical link to increase bandwidth and provide redundancy. For an EtherChannel to function properly, the member ports must share certain settings, which include trunking encapsulation and, typically, the DTP settings. If the DTP negotiation settings differ among the ports, it can lead to issues where not all ports can be bundled together effectively. This means that while using DTP, any variations in how the ports negotiate trunking—whether they are set to negotiate, actively trunk, or are statically configured—can impact the operation of the EtherChannel. In contrast, the channel group number must be identical across all ports that are part of the EtherChannel, as it designates the logical group. IP addresses are not configured on individual ports in an EtherChannel; instead, the entire EtherChannel can have a single IP address assigned to it when it operates as a routed interface or a VLAN. Lastly, speed and duplex settings must also match across all ports in the EtherChannel; if they do not, the EtherChannel would either fail to form or operate