Exam 400-007 topic 1 question 122 discussion

A) Yes. The spanning tree algorithm used by MSTP is RSTP which provides quick convergence. B) No. 802.1s is from IEEE not Cisco. C) No. 802.1s has maximum 16 instance of RSTP. D) Yes. One or more VLANs can be mapped to one MSTP instance E) No. The CPU and memory requirements are less than for Rapid PVST+ but more than for RSTP. https://www.ciscopress.com/articles/article.asp?p=2832407&seqNum=5 https://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/24248-147.html

Answer is CD

C and D apply solely to MST while A is generally true about MST and D mapping many instances to a single Process could also be done using CST as well. Please correct me if i am wrong. E is wrong in every sense. you usually opt for MST to save on CPU and MEM. Answers CD

802.1s provides for faster convergence over 802.1D and PVST+ 802.1s is a Cisco enhancement to 802.1w. 802.1s supports up to 1024 instances of 802.1w. 802.1s maps multiple VLANs to the same spanning-tree instance. CPU and memory requirements are the highest of all spanning-tree STP implementations.

A. 802.1s provides for faster convergence over 802.1D and PVST+: This statement is incorrect. 802.1s is not specifically designed for faster convergence. Rapid Spanning Tree Protocol (RSTP) or 802.1w is the protocol that provides faster convergence compared to the original Spanning Tree Protocol (STP) or 802.1D. B. 802.1s is a Cisco enhancement to 802.1w: This statement is correct. 802.1s, also known as Multiple Spanning Tree Protocol (MSTP), is an enhancement to 802.1w RSTP. It allows for the mapping of multiple VLANs to the same spanning-tree instance, providing greater scalability and reducing the number of spanning-tree instances required.

BD. C is not b/c the mst's maximum instances are 16

BCD is correct