In RSTP, an alternate port is on the same switch as a designated Port.

The statement is false because it incorrectly describes the relationship that defines an Alternate Port. An Alternate Port in Rapid Spanning Tree Protocol (RSTP) provides a redundant, non-forwarding path toward the Root Bridge. It is a backup for the switch's Root Port. An Alternate Port is established when a port receives superior Bridge Protocol Data Units (BPDUs) from a Designated Port on a different (neighboring) switch.

The scenario described in the question—where a port provides redundancy for a Designated Port on the same switch (for example, when two ports on a switch are connected to the same hub or collision domain)—defines a Backup Port, not an Alternate Port.

The statement is not True. While it is possible for a switch to have both an Alternate Port and a Designated Port simultaneously (on different network segments), this is not the defining characteristic of an Alternate Port. The question implies a definitional relationship that is specific to the Backup Port role. The core distinction is that an Alternate Port is a backup for a Root Port, whereas a Backup Port is a backup for a Designated Port.

1. IEEE Std 802.1D-2004, "IEEE Standard for Local and metropolitan area networks—Media Access Control (MAC) Bridges":

Section 17.4, Port Roles: This section formally defines the RSTP port roles. It specifies: "An Alternate Port...receives more useful Designated Bridge information from another Bridge than the Root Port...". It also defines a Backup Port: "A Backup Port...receives more useful Designated Bridge information from the same Bridge it is on...". This directly contradicts the question's statement for an Alternate Port.

2. Nokia 7750 SR OS Services Architecture Guide, Release 21.10.R1:

Chapter: Spanning Tree Protocol (STP), Section: RSTP: The documentation defines the port roles consistent with the IEEE standard. It describes an Alternate port as providing "an alternate path to the root bridge from the root port." It defines a Backup port as providing "a redundant path to a segment where another bridge port already connects... A backup port exists when a bridge has two or more connections to the same segment... The backup port is the port that is not the designated port." This confirms the question is describing a Backup Port's relationship, not an Alternate Port's.