Specifications
Table Of Contents
- Table of Contents
- Preface Template Formats
- Web-based (GUI) Configuration
- Configuration
- Device Information
- System Information
- Serial Port Settings
- IP Address Settings
- IPv6 Address Settings
- IPv6 Route Settings
- IPv6 Neighbor Settings
- Port Configuration Folder
- Static ARP Settings
- User Accounts
- System Log Configuration Folder
- DHCP Relay Folder
- MAC Address Aging Time
- Web Settings
- Telnet Settings
- CLI Paging Settings
- Firmware Information
- SNTP Settings Folder
- SMTP Settings Folder
- SNMP Settings Folder
- Layer 2 Features
- Jumbo Frame
- VLANs
- 802.1Q Static VLAN
- Q-in-Q Folder
- 802.1v Protocol VLAN Folder
- GVRP Settings
- Asymmetric VLAN Settings
- MAC-based VLAN Settings
- PVID Auto Assign Settings
- Port Trunking
- LACP Port Settings
- Traffic Segmentation
- IGMP Snooping Folder
- MLD Snooping Settings
- Port Mirror
- Loopback Detection Settings Page
- Spanning Tree Folder
- Forwarding & Filtering Folder
- LLDP Folder
- Quality of Service (QoS)
- Security
- Access Control List (ACL)
- Monitoring
- Save and Tools
- System Log Entries
- Trap List
Chapter 3: Layer 2 Features
Extreme Networks EAS 100-24t Switch Software Manual
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All three protocols calculate a stable topology in the same way. Every segment will have a single path to
the root bridge. All bridges listen for BPDU packets. However, BPDU packets are sent more frequently -
with every Hello packet. BPDU packets are sent even if a BPDU packet was not received. Therefore,
each link between bridges is sensitive to the status of the link. Ultimately this difference results in faster
detection of failed links, and thus faster topology adjustment. A drawback of STP is this absence of
immediate feedback from adjacent bridges.
RSTP is capable of a more rapid transition to a forwarding state - it no longer relies on timer
configurations - RSTP compliant bridges are sensitive to feedback from other RSTP compliant bridge
links. Ports do not need to wait for the topology to stabilize before transitioning to a forwarding state.
In order to allow this rapid transition, the protocol introduces two new variables: the edge port and the
point-to-point (P2P) port.
Edge Port
The edge port is a configurable designation used for a port that is directly connected to a segment
where a loop cannot be created. An example would be a port connected directly to a single workstation.
Ports that are designated as edge ports transition to a forwarding state immediately without going
through the listening and learning states. An edge port loses its status if it receives a BPDU packet,
immediately becoming a normal spanning tree port.
P2P Port
A P2P port is also capable of rapid transition. P2P ports may be used to connect to other bridges. Under
RSTP/MSTP, all ports operating in full-duplex mode are considered to be P2P ports, unless manually
overridden through configuration.
STP/RSTP/MSTP Compatibility
MSTP or RSTP can interoperate with legacy equipment and is capable of automatically adjusting BPDU
packets to STP format when necessary. However, any segment using STP will not benefit from the rapid
transition and rapid topology change detection of MSTP or RSTP. The protocol also provides for a
variable used for migration in the event that legacy equipment on a segment is updated to use RSTP or
MSTP.
The Spanning Tree Protocol (STP) operates on two levels:
1 On the switch level, the settings are globally implemented.
2 On the port level, the settings are implemented on a per user-defined group of ports basis.
MSTP RSTP STP Forwarding Learning
Disabled Disabled Disabled No No
Discarding Discarding Blocking No No
Discarding Discarding Listening No No
Learning Learning Learning No Yes
Forwarding Forwarding Forwarding Yes Yes