configure stpd default-encapsulation

configure stpd stpd_name default-encapsulation [dot1d | emistp | pvst-plus]

Description

Configures the default encapsulation mode for all ports added to the specified STPD.

Syntax Description


`stpd_name`	Specifies an STPD name on the switch.
dot1d	Specifies the STP encapsulation mode of operation to be 802.1d.
emistp	Specifies the STP encapsulation mode of operation to be EMISTP.
pvst-plus	Specifies the STP encapsulation mode of operation to be PVST+.

Default

Ports in the default STPD (s0) are dot1d mode.

Ports in user-created STPDs are in dot1d mode.

Usage Guidelines

Care must be taken to ensure that ports in overlapping domains do not interfere with the orderly working of each domain‘s protocol.

By default, when the switch boots for the first time, it automatically creates a VLAN named default with a tag value of 1 and STPD s0. The switch associates VLAN default to STPD s0. All ports that belong to this VLAN and STPD are in 802.1d encapsulation mode with autobind enabled. If you disable autobind on the VLAN default, that configuration is saved across a reboot.

MSTP STPDs use 802.1D BPDU encapsulation mode by default. To ensure correct operation of your MSTP STPDs, do not configure EMISTP or PVST+ encapsulation mode for MSTP STPDs.

Naming Conventions

If your STPD has the same name as another component, for example a VLAN, we recommend that you specify the identifying keyword as well as the name. If your STPD has a name unique only to that STPD, the keyword stpd is optional. For name creation guidelines and a list of reserved names, see Object Name in the Switch Engine 32.3 User Guide .

STP Encapsulation Modes

You can specify the following STP encapsulation modes:

dot1d—This mode is reserved for backward compatibility with previous STP versions. BPDUs are sent untagged in 802.1D mode. Because of this, any given physical interface can have only one STPD running in 802.1D mode.
This encapsulation mode supports the following STPD modes of operation: 802.1D, 802.1w, and MSTP.
emistp—This mode sends BPDUs with an 802.1Q tag having an STPD ID in the VLAN ID field.
This encapsulation mode supports the following STPD modes of operation: 802.1D and 802.1w.
pvst-plus—This mode implements PVST+ in compatibility with third-party switches running this version of STP. The STPDs running in this mode have a one-to-one relationship with VLANs and send and process packets in PVST+ format.
This encapsulation mode supports the following STPD modes of operation: 802.1D and 802.1w.

Note

These encapsulation modes are for STP ports, not for physical ports. When a physical port belongs to multiple STPDs, it is associated with multiple STP ports. It is possible for the physical port to run in different modes for different domains for which it belongs.

STPD Identifier

An StpdID is used to identify each STP domain. You assign the StpdID when configuring the domain. An STPD ID must be identical to the VLAN ID of the carrier VLAN in that STP domain, and that VLAN cannot belong to another STPD.

MSTP uses two different methods to identify the STPDs that are part of the MSTP network. An instance ID of 0 identifies the Common and Internal Spanning Tree (CIST). The switch assigns this ID automatically when you configure the CIST STPD. A multiple spanning tree instance identifier identifies each STP domain that is part of an MSTP region. You assign the MSTI ID when configuring the STPD that participates in the MSTP region. In an MSTP region, MSTI IDs only have local significance. You can reuse MSTI IDs across MSTP regions.

Example

The following example specifies that all ports subsequently added to the STPD STPD1 be in PVST+ encapsulation mode unless otherwise specified or manually changed:

configure stpd stpd1 default-encapsulation pvst-plus

History

This command was first available in ExtremeXOS 10.1.

Platform Availability

This command is available on ExtremeSwitching 5320, 5420, 5520, and 5720 series switches.