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Ethernet Case

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STP (802.1d)

Prevent L2 loops and provide redundancy

Port stats:

Blocking RX PBDU, No MAC table building, No data

Listening RX & TX PBDUs (Participate in election) 15 sec forward delay , No MAC table no data

Learning RX PBDU, TX PBDU, MAC table

Forwarding RX PBDU, TX PBDU, MAC table, data transfer

Root bridge ID (64 Bytes): Bridge Priority (2 Bytes)+MAC address (6 BYTEs) lowest is the choice default is 32768

BPDU are of 2 types, configuration (used for root bridge election) and TCN (Topology change notification)

Port Roles

RSTP (IEEE 802.1w)

Root Port: Receive best BPDU (generated by Root bridge)

Designated Port: Transmit best BPDU

Alternate Port: Recive better BPDU from another bridge

Backup port: receive better PBDU From the local bridge

Ports states: discarding, learning and forwarding

Port Roles: Root Port, Designated Port, Blocked port, Alternate Port and Backup port


* Non-root bridge generate PBDUs - HELLO packets in 2 secs.(helps in fast aging)

* Fast Aging

* Backbone FAST


* Edge port (skip listening and learning states...saves 30 secs.)

* If you have pt. to pt link skip listening and learning states...saves 30 secs

* Any link that is in Full counts it as pt to pt link

* SYNC Operation (Proposal PBDU, Agreement PBDU). Fast backbone convergence



Technology that combines the BW of multiple physical links into a single logical channel

Three types: FAST, GIGABIT

Channel range: 2-8

Link requirements to be in etherchannel: Same speed, same duplex, same VLAN, Port contiguous (depending about platform)


Increased BW, load balancing, Fault tolerance (with in one second, while in normal STP it took 30 secs and at UPLINK FAST it took 1-5 secs.)

Port aggregation protocol (PAgP) - etherchannel either ON or



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