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Chapter 2

von Roza Roza

Inside A computer

von Luke Cantley

Agency Planning

von Stewart Bronaugh

CAT-FDP-8.14-View

von Cat Henry

STP TERMS

EDGE PORT

PATH-COST

ETHERNET-100 FAST ETHERNET-19 GIGA ETHERNET-4 10 GIGA ETHERNET-2

COST TO REACH THE ROOT

ETHERNET-100

FAST ETHERNET-19

GIGA ETHERNET-4

10 GIGA ETHERNET-2

BRIDGE-ID

DEFAULT PRIORITY 32768

PRIORITY(16Bits) + MAC-ADDRESS(48Bits)

NAME OF SWITCH

NON-EDGE PORT

GENERATES TC(TOPOLOGY CHANGE) BPDUs

PARTICIPATE IN STP ALGORITHM

ROOT BRIDGE

SWITCH HAVING LOWEST BRIDGE-ID

BRIDGE PROTOCOL DATA UNIT(BPDU)

TCN(TOPOLOGY CHANGE NOTIFICATION) BPDU ONLY AFTER TOPOLOGY CHANGE

CONFIGURATION BPDUs(AFTER EVERY 2 SEC)

DECISION SEQUENCE IN STP

LOWEST BRIDGE-ID

LOWEST PATH COST

LOWEST SENDER BRIDGE-ID

LOWEST PORT-PRIORITY

LOWEST PORT-ID

STP CONVERGENCE STEPS:-

BLOCKED PORT

CAN RECIEVE & SEND BPDUs IN RSTP

ONLY RECIEVE BPDUs IN PVST & CST

ROOT PORT-ELECTION

PORT TO REACH THE ROOT

DESIGNATED PORT ELECTION

ELECTED PER SEGMENT BASIS

ROOT ELECTION

ALL PORTS ARE DESIGNATED PORTS

WHY STP???

TO MAINTAIN REDUNDANCY

TO PREVENT LAYER 2 LOOPS

SPANNING TREE (falling of tree)

RAPID SPANNING-TREE(802.1D)

PORT STATES-

DISCARDING

LEARNING

FORWARDING

PORT ROLES- ROOT DESIGNATED BLOCKING ALTERNATE BACKUP

PORT STATES- DISCARDING LEARNING FORWARDING

NO LONGER THAN 15 SECONDS IS NEEDED TO GO FROM DISCARDING TO FORWARDING STATE

NO LISTENING STATE

COMMON SPANNING TREE(802.1D)

30 SECONDS DELAY FROM BLOCKING TO FORWARDING

LESS CPU LOAD

ONE INSTANCE

ONE ROOT-BRIDGE FOR ALL VLAN

MULTIPLE SPANNING-TREE(802.1S)

UPTO 8 VLANS CAN BE GROUPED UNDER 1 INSTANCE

ONE INSTANCE FOR A GROUP OF VLANS

PER VLAN SPANNING-TREE PLUS(CISCO)

PORT STATES-

DISABLED

BLOCKING

LISTENING

LEARNING

FORWARDING

PORT ROLES- ROOT DESIGNATED BLOCKING

PORT STATES- DISABLED BLOCKING LISTENING LEARNING FORWARDING

MORE CPU OVERHEAD NEEDED

ROOT-BRIDGE FOR EACH & EVERY SINGLE VLAN