Spanning Tree Protocol and RSTP Overview

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Questions and Answers

What is the consequence of turning off Spanning Tree Protocol (STP) in a switched network?

The network will operate with lower latency.

The network becomes unusable due to broadcast storms. (correct)

There will be enhanced security features.

The network will have a higher throughput.

What should be done first if a Spanning Tree failure occurs?

Reconfigure the entire network.

Increase the STP timers.

Manually remove redundant links. (correct)

Turn off all switches in the network.

What is the role of the stack master in a switch stack?

It controls switch operations and stores configuration files. (correct)

It handles all physical cable connections.

It manages the network clock.

It serves as a backup for all other switches.

How does a switch stack affect the STP diameter when adding more switches?

The STP diameter reduces with a properly managed switch stack. Signup and view all the answers

What is the recommended maximum diameter for switches using default STP timers?

7 switches Signup and view all the answers

What is assigned to the switch stack as a whole in the network?

One IP address Signup and view all the answers

What is the forwarding delay timer's default setting in the Spanning Tree Protocol?

15 seconds Signup and view all the answers

In terms of stack member priority, what determines which switch becomes the stack master?

The highest stack member priority value Signup and view all the answers

What is the primary benefit of Rapid PVST+ over standard Spanning Tree Protocol (STP)?

It allows for multiple instance processing per VLAN. Signup and view all the answers

Which feature is NOT compatible with switches running RSTP?

BackboneFast Signup and view all the answers

How does RSTP signify a lost connectivity in its operation?

By detecting an absence of 3 consecutive BPDUs. Signup and view all the answers

What is the defining characteristic of an edge port in RSTP?

Immediately transitions to the forwarding state. Signup and view all the answers

What type of port connection does RSTP define as Point-to-Point?

A full-duplex connection between two switches. Signup and view all the answers

Which of the following statements about RSTP BPDUs is true?

Type 2, version 2 BPDUs are utilized. Signup and view all the answers

What is an essential function of the `spanning-tree portfast` command?

It allows a port to transition immediately to forwarding. Signup and view all the answers

What happens if RSTP detects a shared link type?

It configures the port in half-duplex mode. Signup and view all the answers

What is the protocol version set to in an 802.1D BPDU frame?

0 Signup and view all the answers

Which bit in the BPDU frame indicates a topology change?

Flags bit Signup and view all the answers

During STP operation, what happens when a switch is powered on?

It assumes it is the root bridge until BPDUs are sent. Signup and view all the answers

What does an STP switch do with a BPDU from another switch that has a higher Bridge ID?

Ignores the information from that switch. Signup and view all the answers

What is the purpose of the 'Max age' field in a BPDU?

Decides how long the current configuration message will be retained. Signup and view all the answers

What does a switch do after it has updated its root ID based on a received BPDU?

Sends out BPDUs on all ports to indicate the new root. Signup and view all the answers

What is the role of the 'Hello time' in STP?

Indicates the time interval between each BPDU sent on a port. Signup and view all the answers

Which piece of information does the 'Root path cost' field convey in a BPDU?

The aggregated cost to reach the root bridge. Signup and view all the answers

Study Notes

ICMPv6 Neighbor Discovery

ICMPv6 Neighbor Discovery defines five different packet types
Router Solicitation Message, used with dynamic address allocation
Router Advertisement Message, used with dynamic address allocation
Neighbor Solicitation Message, used with address resolution (IPv4 ARP)
Neighbor Advertisement Message, used with address resolution (IPv4 ARP)
Redirect Message, similar to ICMPv4 redirect messages (Router-to-Device messaging)

Dynamic Address Allocation in IPv4

Dynamic addressing in IPv4 uses DHCPv4 server
A device requests an IP address from the server
The server assigns an address to the device

Dynamic Address Allocation in IPv6

Dynamic addressing in IPv6 uses ICMPv6 Router Solicitation and ICMPv6 Router Advertisement
SLAAC, Stateless DHCPv6, Stateful DHCPv6 are used for allocation.

RA Message Options

ICMPv6 Router Advertisement Option 1, 2, or 3
Other Configuration ("O") Flag
Managed Configuration ("M") Flag
Configuring Flags discussed in Lesson 8

Option 3 and the "A" Flag

ICMPv6 RA, M Flag = 1, A Flag = 0
Autonomous address configuration (A) flag tells hosts they can create an address for themselves by combining the prefix in the RA with an interface identifier
Configuring Flags discussed in Lesson 8

Router Solicitation/Router Advertisement

Router Solicitation is sent when a device needs IPv6 addressing information
Router Advertisement is sent every 200 seconds or in response to RS.

Analyzing the Router Solicitation Message

To: FF02::2 (All-IPv6 Routers)
From: FE80::50A5:8A35:A5BB:66E1
ICMPv6 Router Solicitation

Analyzing the Router Advertisement Message

To: FF02::1 (All-IPv6 devices)
From: FE80::1 (Link-local address)
ICMPv6 Router Advertisement

Neighbor Solicitation and Neighbor Advertisement

NS: Multicast, NS: Solicited Node Multicast, Ethernet
NA: Unicast, NA: Unicast, IPv6 Header, ICMPv6: Neighbor Solicitation/Advertisement

ICMPv6 Redirect

Similar functionality to ICMPv4
A router informs an originating host of the closer IP address of a router.
Unlike IPv4, a router informs an originating host that the destination host is on the same link.

ICMPv6 Duplicate Address Detection (DAD)

Duplicate Address Detection (DAD) is used to confirm unique IPv6 unicast addresses on a link.
A device sends a Neighbor Solicitation for its own unicast address
If no Neighbor Advertisement is received, the address is deemed unique
Once required, RFC updated to recommend /64 interface ID for uniqueness.

Neighbor Cache

Neighbor Cache maps IPv6 addresses to Ethernet MAC addresses
Similar to ARP Cache for IPv4
5 states: Reachable, Stale, Incomplete, Delay, Probe

VLSM and CIDR

Prior to 1981, IP addresses used the first 8 bits to specify the network portion of the address.
In 1981, RFC 791 modified the IPv4 address to allow for three different classes.
IP address space was depleting rapidly.
The IETF introduced Classless Inter-Domain Routing (CIDR).
CIDR uses Variable Length Subnet Masking (VLSM) to help conserve address space.
VLSM is a way of subnetting a subnet.

Classful and Classless IP Addressing

Classful IP addressing is based on the first octet
Initiatives to conserve IPv4 address space include: VLSM & CIDR notation, Network Address Translation, and Private Addressing
Classful addresses are identified by the decimal number of the 1st octet (Class A, B, C)
The IPv4 Classful Addressing Structure (RFC 790) had the network and host portions
Subnet mask is used to determine network and host portion of an IP address.
Classful routing protocols (like RIPV1) did not send subnet masks.
Classless Inter-domain Routing (CIDR) improves efficiency and requires subnet masks in routing updates

STP

Build a simple switched network with redundant links
Explain common problems in a redundant, switched network.
Build a simple switched network using STP.
Describe different spanning tree varieties
Explain PVST+ and Rapid PVST+

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Description

This quiz explores the intricacies of Spanning Tree Protocol (STP) and Rapid Spanning Tree Protocol (RSTP) in switched networks. It covers concepts such as stack master roles, STP diameter, forwarding delays, and the benefits of RSTP over standard STP. Test your understanding of these critical network protocols and their features.