06 M3 SAN Topologies

7/28/2019 06 M3 SAN Topologies

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2006 Hewlett-Packard Development Company, L.P.

The information contained herein is subject to change without notice

SAN Topologies

Module 3


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Rev. 6.21 HP Restricted 1

Objectives

Describe these SAN topologies:

Point-to-point

Arbitrated loop

Switched fabric


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Point-to-point topology

Is inexpensive

Uses full bandwidth

Connects two devices only


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Arbitrated loop topology

Node BNode A

NL_

Port0

Transmitter

Receiver

NL_Port1Receiver

Node CNode D

NL_

Port3

Transmitter

Receiver

NL_Port2

Transmitter

Receiver

Fibre Channel hub

Transmitter


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Arbitrated loop hubs

Provide a physical star topology for a loop configuration

Complete connections between transmitters and receiverson a port-by-port basis through multiplexer circuitry

Finish the loop by connecting the transmitter of the last hub

port to the receiver of the first

Have bypass circuitry at each port

Enables the loop to circumvent a disabled or disconnected

node


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Fibre Channel HUB

Switched fabric topology

Node B

N_

Por

t0

F_

Port

Transmitter

Receiver

N_Port1

Transmitter

Receiver

Node A

F

_Port

Receiver

Transmitter

Node A

NL_

Por

t0

Transmitte

r

Receiver

FL_Port

Transmitter

Receiver

FC_AL

NL_Ports

Fabric

Node B

NL_P

or

t0

Receiver

Transmitte

r

Node D

NL_

Por

t0

Transmitte

r

Receiver

N_

Port0

Transmitter

Receiver


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World-Wide Names

64-bit unique identifier for each Fibre Channel node

Not used for routing traffic across network

Used to preserve identity of a node if its FC-2 or FC-3 layer

address is changed



Loop addressing

AL_PA is assigned during the loop initialization

The highest-priority port on the loop becomes loop masterto manage the generation of a positional map of the loop

In a public loop, the switch has ALPA 00 and becomes master

In a private loop the node with the lowest ALPA becomes

master The loop master transmits frames to identify existing nodes

and allow new nodes to obtain an ALPA/LOOP_ID

In a public loop the switch looks for fabric assigned addresses

(LIFA) L_Ports report their position (LIRP)

After the AL_PA bit map has returned to the loop master it

contains a complete map of all the ports on the loop

The loop master transmits the completed frame so that allthe orts on the loo can ca ture the com leted ositional



Private loop

A private loop can accommodate up to 126 NL_ports

Contains only devices which are not fabric-aware

Cannot communicate with fabric devices

NL_Port

NL_Port

NL_Port

NL_Port

NL_Port

Loop 1

Hub



Translative mode

Public loopPublic loop

Private nodePublic nodes

Public loop address Private loop address

Fabric assigned address

LL LL PP 00 00 PP

NN NN NN

Fabric direct attach nodes

N N

NL

NL

NL

FL FL

F F



Public loop

A public loop can accommodate up to 126 NL_ports and one

FL_port The FL_port extends the number of nodes for communication

HUB

NL_Port

NL_Port

NL_Port

NL_Port

NL_Port NL_Port

NL_Port

NL_Port

NL_Port

NL_Port

HUB

FL_Por

t

FL_Por

t

FL_Po

rt

FL_Po

rt

FL_Po

rt

FL_Port

Loop 2Loop 1

To other L_Ports

or F_Ports



Port logins

PLOGI is performed immediately after loop initialization:

Server attempts to login to all devices on the loop by issuingPLOGI frames addressed to each possible AL_PA address

Targets that accept the PLOGI will return an ACC frame



Fabric addressing B series



Simple name server

Target discovery for an arbitrated loop is performed by

PLOGI to all 126 AL_PA device addresses Name server function resides within each switch

Device drivers may register values for:

24-bit address

64-bit port WWN

64-bit node WWN

Class of service parameters

FC-4 protocols supported

Port type



Learning

check


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06 M3 SAN Topologies

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