Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) User Manual
Page 486
Spanning Tree Introduction: STP, RSTP, and MSTP
Software Reference for x310 Series Switches
18.18
AlliedWare Plus
TM
Operating System - Version 5.4.4C
C613-50046-01 REV A
Version 3 Length
37–38
Used to convey the Version 3 length. It is the number
of octets taken by the parameters that follow in the
BPDU.
MST Configuration
Identifier
39–89
An identifier comprising elements of the following:
Format Selector
Configuration Name
Revision Level
Configuration Digest.
CIST Internal Root
Path Cost
90–93
Path cost to the CIST regional root.
CIST Bridge
Identifier
94–101
CIST bridge identifier of the transmitting bridge.
CIST Remaining
Hops
102
Remaining hops which limits the propagation and
longevity of received spanning tree information for the
CIST.
MSTI Configuration
Messages
(may be absent)
103–39
plus
Version
3
Length
Table 18-8: MSTI configuration messages
Field Name
Octets
Description
MSTI Flags
1
Bits 1 through 8, convey the topology change flag,
proposal flag, port role (two bits), Learning flag,
forwarding flag, agreement flag, and master flag for
this MSTI.
MSTI Regional Root
Identifier
2–9
This includes the value of the MSTID for this
configuration message encoded in bits 4 through 1 of
octet 1, and bits 8 through 1 of octet 2.
MSTI Internal Root
Path Cost
10-13
Internal Root Path Cost.
MSTI Bridge Priority
14
Bits 5 through 8 convey the value of the bridge
identifier priority for this MSTI. Bits 1 through 4 of Octet
14 are transmitted as 0, and ignored on receipt.
MSTI Port Priority
15
Bits 5 through 8 are used to convey the value of the
port identifier priority for this MSTI. Bits 1 through 4 are
transmitted as 0, and ignored on receipt.
MSTI Remaining
Hops
16
Value of remaining hops for this MSTI.
Table 18-7: MSTP Bridge Protocol Data Units (BPDUs)(cont.)
Field Name
Octets
Description