Ethernet Case

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

Enhancements:

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

* Fast Aging

* Backbone FAST

* PSEDO PORT 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 duplex...it counts it as pt to pt link

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

*

Ethernchannel

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)

Benefits:

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