Cisco Catalyst 2960-XR Configuration Guide

After ensuring that all of the ports are synchronized, the switch sends an agreement message to the designated
switch corresponding to its root port. When the switches connected by a point-to-point link are in agreement
about their port roles, the RSTP immediately transitions the port states to forwarding.
Figure 9: Sequence of Events During Rapid Convergence
Bridge Protocol Data Unit Format and Processing
The RSTP BPDU format is the same as the IEEE 802.1D BPDU format except that the protocol version is
set to 2. A new 1-byte Version 1 Length field is set to zero, which means that no version 1 protocol information
is present.
Table 11: RSTP BPDU Flags
FunctionBit
Topology change (TC)0
Proposal1
Port role:
Unknown
Alternate port
Root port
Designated port
2–3:
00
01
10
11
Learning4
Forwarding5
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
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Configuring Multiple Spanning-Tree Protocol
RSTP Overview

Cisco Catalyst 2960-XR Specifications

General

Stacking Bandwidth	80 Gbps
Layer Support	Layer 2 and Layer 3
Jumbo Frame Support	9198 bytes
RAM	512 MB
Input Voltage	100-240V AC
Model	Catalyst 2960-XR
Uplink Interfaces	4 x 1G SFP or 2 x 10G SFP+
Downlink Interfaces	24 or 48 x Gigabit Ethernet ports
Power Supply	Internal
MAC Address Table Size	16, 000 entries
PoE	Available on PoE models
Weight	4.5 kg
Features	energy efficiency
Stacking	Up to 8 switches
Operating Temperature	0 to 45°C