ADTRAN Vanta 1335 Bedienungsanleitung PDF herunterladen (Seite 9)

US

8,380,828

B1

5

throughout

the

network

(block

54).

A

determination

is

made

that

if

the

offending

device

is

found

in

the

sWitch’s

database,

Was

it

found

on

a

port

that

does

not

have

an

LLDP

neighbor

(block

55).

If

yes,

the

offending

netWork

device

is

located

(block

56).

The

sWitch

having

the

offending

netWork

device

connected

thereto

disables

the

sWitch

port

to

Which

the

offending

netWork

device

is

connected

or

blocks

all

data

tra?ic

from

the

MAC

address

of

the

offending

netWork

device

(block

58).

For

example

this

is

accomplished

using

the

dis

covery

protocol

frame

that

includes

a

command

that

instructs

any

sWitch

having

the

offending

netWork

device

connected

thereto

to

disable

the

sWitch

port or

block

all

data

tra?ic

from

that

MAC

address.

The

process

ends

as

noted

at

block

60.

If

the

offending

device

is

not

found

in

the

sWitch’

s

database

and/

or

it

Was

not

found

on

a port

that

does

not

have

an

LLDP

neighbor,

then

the

LLDP

message

Will

propagate

and

repeat

until

the

MAC

address

is

found

and

there

is

no

LLDP

neigh

bor

(block

62).

This

process

continues

as

shoWn

by

the

loop

back

from

block

62

to

block

55.

There

noW

folloWs

a

brief

description

of

LLDP

relative

to

the

communications

netWork

shoWn

in

FIG.

1

and

that

can

be

applied

for

purposes

of

understanding.

LLDP

is

a

common

protocol

used

to

exchange

information

betWeen

netWork

sWitches.

With

LLDP,

each

netWork

sWitch

has

visibility

of

its

neighboring

sWitches.

Network

devices,

such

as

Ethernet

devices

and

sWitches, advertise

information

about themselves

and

store

information

in

local

Management

Information

Base

(MIB)

databases

and

associated

With

net

Work

devices

and

accessible via the

Simple

Management

NetWork

Protocol

(SMNP).

This information

can

be

used

to

build

a

netWork

topology

map

using

a

NetWork

Management

Station

(NMS)

such

as

associated

With

an

administrator

26

or

other

device

as

illustrated.

LLDP

is

a

technique

used

for

Ethernet

netWork

devices,

including

sWitches,

routers

and

Wireless

LAN

access

points

and

other

netWork

devices

to

advertise

information

about

themselves

to

other

nodes

on

the

netWork

and

store

informa

tion

they

discover

using

the

MIB

in

one

non-limiting

example.

The

details

that

are

shared

include

the

netWork

device

capabilities,

identi?cation

(such

as

the

MAC

address),

and

device

con?guration.

LLDP

is

typically

a

one-Way

neigh

bor

discovery

protocol

With

periodic

transmissions.

The

LLDP

frames

are

typically

constrained

to

a

single

length.

The

frames

contain

formatted

Type

Length

Values

(TLV’

s),

Which

carry

information

regarding

a

globally

unique system

and

port

identi?cation, time-to-live

information

for

aging

pur

poses, optional

system

capabilities

and

optional

system

names

and

descriptions

and

management

addresses

such

as

IPV4

and

IPV6.

LLDP

in

one

aspect

is

covered

by

the

IEEE

standard,

802.1AB

Link

Layer

Discovery

Protocol

(LLDP),

the

disclo

sure

Which

is

hereby

incorporated

by

reference

in

its

entirety.

LLDP

is

advantageous

over

netWork-management

tools

such

as

reading

bridge

tables

from

an

SNMP

bridge

MIB

in

Which

algorithms

decide

for

the

bridge

tables

and

map

the

port-to

MAC

address

entries.

For

example,

if

a

netWork

uses

the

spanning

tree

protocol,

the

sWitch

at

the

bottom

of

a

con?gu

ration

has

ports

of

a

single

segment

or

netWork

device

and

each

port

of

a root

sWitch

contains

the

sum

total

of

the net

Work

devices

beloW

it

in

its

bridge

table.

Bridge

tables

are

not

alWays

accurate.

LLDP

is

also

advantageous

over

fractal

matching.

With

LLDP,

each

netWork

device

on

each

port

stores

infor

mation

de?ning

itself

and

sends

updates

to

a

connected

neigh

bor,

Which

then

stores

the

information

in

standard

SNMP

MIB’s.

Thus,

information gathered

With

LLDP

is

stored

in

a

netWork

device

and

is

queried

With

SNMP

techniques.

Typi

20

25

30

35

40

45

50

55

60

65

6

cally,

the

topology of

an

LLDP-enabled

netWork

is

discov

ered

by

“craWling”

the hosts

and

querying

a

database.

This

is

time

consuming

as

noted

above.

“CraWling” can

obtain

infor

mation

regarding

a

system

name

and

description,

port

name

and

description,

VLAN

name,

IP

management

address,

sys

tem

capabilities

such

as

sWitching

and

routing,

the

MAC/

PHY

information

and

other

link

aggregation

information.

In

one

aspect,

LLDP

de?nes

a

set

of

common

advertise

ment

messages

and

a

protocol

for

transmitting the

advertise

ments

and

a

method

for

storing

information

contained

in

the

received

advertisements.

Typically,

LLDP-capable

netWork

devices

support

device

chassis

ID

and

port

ID

advertisements

and

support

system

name,

system

description

and

system

capabilities

advertisements.

Typically,

LLDP

information

is

transmitted

periodically

and

stored

for

a ?nite

period.

One

recommended

transmission

rate

is

about

30

seconds,

but

this

can

be

adjustable.

Usually,

the

information

stored

in

the

SNMP

MIB

is

valid

for

a

period

of time

de?ned

by

the

LLDP

“time

to live”

(TTL)

value

as

contained

Within

a

received

packet.

One

recommendation

is

a

TTL

value

of

about

120

seconds,

but

it

can

be

set

to

a

maximum

value

of

about

65,000

seconds

or

a

minimum

value

of 0

seconds.

Typically,

a net

Work

device

receives

an

LLDP

advertisement packet

and

stores

the

information

Within

it

and

initialiZes

a

timer

that

Will

be

compared

to

the

TTL

value.

If

the

timer

reaches

the

TTL

value,

the

netWork

device

deletes

the stored

information,

and

thus,

ensures

that

only

valid

LLDP

information

is

available

to

NetWork

Management

Systems.

It

should

be

understood

that

LLDP

frames

typically

are

not

forWarded,

but

constrained

to

a

single link

and

contain

formatted

TLV’s

as

type

length

values

that

carry

the

globally

unique

system

and

port

identi

?cation,

time-to-live

information

for

aging

purposes,

optional

system

capabilities

such

as

the

router,

IP

phone,

and

Wireless

AP

and

optional

system

name

and

description,

man

agement

addresses

and

organizational

extensions.

Typically,

each

LLDP-enabled

netWork

device

contains

one

or

several

LLDP

agents

such

as

an

LLDP

state

machine

that

controls

the

transmission

and

receipt

of frames

and

state

machine

control

variables.

The

local

MIB

holds

the

locally

con?gured

data

that

could

be

supplied

or

modi?ed

by

man

agement

applications

of

a

management

system.

Remote

MIB’s

hold

and

age

data

as

received.

Usually

the

LLDP

frame

contains

an

LLDP

multicast

address

that

is

about

six

bytes

as

a

destination

address

and

a

MAC

address

of

about

six

bytes

and

an

LLDP

ether

type

of

about

tWo

bytes

and

the

LLDPU

that

is

data

plus

padding

and

the

PCS.

An

LLDPU

?eld

contains

the

TLV’

s

as

a

chassis

ID,

port ID,

TTL

and

similar

information.

As

noted

before,

in

operation,

a

Link

Layer

Discovery

Protocol

(LLDP)

frame

is

modi?ed

to

alloW

almost

instanta

neous

hunting

and

location

of

the

offending

netWork

device.

As

illustrated,

a

query

message

is

sent

using

LLDP,

originat

ing

from

user

input

on

one

netWork

sWitch

that

propagates

to

all

sWitches

in

the

netWork.

This

query

asks

if

the

netWork

sWitch

has

an

entry

in

its

database

table

for

the

offending

netWork

device

having

the

MAC

address.

If

it

has

an

entry

and

the

MAC

address

Was

learned

on

a port

Where

there

is

not

an

LLDP

neighboring

netWork

sWitch,

the

device

location

has

been

determined.

The

netWork

sWitch

can be

con?gured

to

take

action

automatically

based

on

?nding

the location

of

the

offending

netWork

device.

The

port

can be

automatically

disabled

or a

rule

can be

automatically

added

to

the

netWork

sWitch

to

block

all

tra?ic

from

the

offending

or

fault

netWork

device’s

MAC

address.

In

other

cases,

tra?ic

from

the

MAC

address

corresponding

to

the

offending

netWork

device

is

prevented

from

accessing

the

netWork.

This

solution

can

be

executed

in

seconds

With

minimal

user

intervention

as

com

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