作者：ABHISHEK KUMAR 13 年以前
539
ospf tech
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 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 ROLES-
ROOT
DESIGNATED
BLOCKING
PORT STATES-
DISABLED
BLOCKING
LISTENING
LEARNING
FORWARDING
MORE CPU OVERHEAD NEEDED
ROOT-BRIDGE FOR EACH & EVERY SINGLE VLAN
