The pocket network management survival guide

SECTI O N1: NETWORK TEC H N O LO GI ES

Pa rt 1: Wide A rea Te ch n o l o gies

A . O ve rv i ew. . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 8

B . Frame Relay. . . . . . . . . . . . . . . . . . . . . . . . 9 - 1 0

C . AT M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 - 1 3

D. I S D N . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 4 - 1 5

Pa rt 2: Local A rea Netwo rk Te ch n o l o gi e s

A . O ve rv i ew . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 6

B . E t h e rn e t. . . . . . . . . . . . . . . . . . . . . . . . . . 1 7 - 1 8

C . To ken Ring . . . . . . . . . . . . . . . . . . . . . . . . . . 1 9

D. F D D I . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 0 - 2 1

Pa rt 3: N ewer Serv i c e s

A . The We b . . . . . . . . . . . . . . . . . . . . . . . . . 2 2 - 2 3

B . I n t ra n e t s. . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4

C . E x t ra n e t s . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 5

D. Vi rtual Pri vate Netwo rk s . . . . . . . . . . . . . 2 6 - 2 7

E . M u l t i c a s t i n g . . . . . . . . . . . . . . . . . . . . . . . . . 2 8

F. xDSL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 9

Pa rt 4: N e t wo rk Elements

A . O ve rv i ew. . . . . . . . . . . . . . . . . . . . . . . . . 3 0 - 3 1

B . H u b s . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 - 3 3

C . B ri d ge s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4

D. R o u t e rs . . . . . . . . . . . . . . . . . . . . . . . . . . 3 5 - 3 7

E . S w i t ch e s. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 8

F. Remote Access . . . . . . . . . . . . . . . . . . . . 3 9 - 4 1

G. Fi rewa l l s. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2

H . S e rve rs. . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 - 4 4

I . C l i e n t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 5

C o n c o r d C o m m u n i c a t i o n s , I n c . 1

Th e Po c ke t Ne tw o r k Man a ge m en t Su r vi va l G ui de

Pa rt 5: S t a n d a rd s

A . O ve rv i ew . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 6

B . IETF Standard s

S N M P . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 7

M I B s. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 7

R M O N . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 7

R M O N 2 . . . . . . . . . . . . . . . . . . . . . . . . . . 4 8

M I B 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 8

Other Pro t o c o l s . . . . . . . . . . . . . . . . . . . . 4 9

C . IEEE Standard s

IEEE 802.1 p, q . . . . . . . . . . . . . . . . . . . . . 5 0

IEEE 802.3x . . . . . . . . . . . . . . . . . . . . . . . 5 0

IEEE 802.3z . . . . . . . . . . . . . . . . . . . . . . . 5 0

D. ATM Fo rum Standard s

UNI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1

P N N I . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1

SECTION 2: NETWORK PE R FO R MAN C E

Pa rt 1: O ve rv i ew. . . . . . . . . . . . . . . . . . . . . . . . . 5 2 - 5 3

Pa rt 2: Pe r fo rm a n c e - related Te rm s

A . Ava i l ab i l i t y . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4

B . B a n dw i d t h . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4

C . B a s e l i n e . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 5

D. C o n ge s t i o n . . . . . . . . . . . . . . . . . . . . . . . . . . 5 5

E . L a t e n c y . . . . . . . . . . . . . . . . . . . . . . . . . . 5 5 - 5 6

F. T h re s h o l d . . . . . . . . . . . . . . . . . . . . . . . . 5 6 - 5 7

G. U t i l i z a t i o n. . . . . . . . . . . . . . . . . . . . . . . . . . . 5 7

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Th e Po c ke t Ne two r k Man a ge m en t Su r vi va l G ui de

C o n c o r d C o m m u n i c a t i o n s , I n c .

Pa rt 3: S e rvice Level A gre e m e n t s. . . . . . . . . . . . . . . 5 8

Pa rt 4: S e rvice Level Metri c s

A . Ava i l ab i l i t y . . . . . . . . . . . . . . . . . . . . . . . . . . 5 8

B . Response Ti m e . . . . . . . . . . . . . . . . . . . . . . . 5 9

C . T h ro u g h p u t . . . . . . . . . . . . . . . . . . . . . . . . . 5 9

SECTI O N3: N ETWORK MAN AG E ME NT TO O L BOX

Pa rt 1: O ve rv i ew . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 0

Pa rt 2: Element Manage rs . . . . . . . . . . . . . . . . . . . . 6 1

Pa rt 3: N e t wo rk Management Platfo rm s . . . . . . . 6 2 - 6 3

Pa rt 4: P ro b e s . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4 - 6 8

Pa rt 5: Pe r fo rmance Report i n g / A n a ly s i s . . . . . . . 6 9 - 7 0

SECTION 4 : G LOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1 - 8 0

SECTION 5: S PE E DS AND FE E DS . . . . . . . . . . . . . . . . . . . . . 8 1 - 8 2

C o n c o r d C o m m u n i c a t i o n s , I n c . 3

Th e Po c ke t Ne tw o r k Man a ge m en t Su r vi va l G ui d e

INTRO DUCTI O N

H ave you ever looked up a definition in a so-called “ c o m￾puter glossary ”o n ly to be more confused than ever? T h i s

guide attempts to demystify some of the most commonly

e n c o u n t e red netwo rk management terms and concepts.

We compiled the fo l l owing list based on call-ins to our

t e chnical support group and ongoing input from our cus￾t o m e rs .W h e n ever possibl e ,we tried to avoid using tech￾nical terms so that definitions can be easily read and

u n d e rs t o o d . To make life easier,we ’ve included a bri e f

statement on the “ va l u e ,” “ l i m i t a t i o n s ,” and commonly

held misconceptions re g a rding a concept. In addition,

we direct you to related terms elsew h e re in the book

and in a glossary located in the back of the guide.

Because many of the terms are new, t h e re is not ye t

absolute standardization of meaning. T h u s , one term may

h ave seve ral similar, yet slightly diffe rent meanings.We ’ve

t ried to be as factual as possibl e ,but in the interest of

being clear and concise, m ay unknow i n g ly have interject￾ed our personal pre fe rences and pre j u d i c e s .

We hope yo u ’ll find this pocket book a handy re fe re n c e

guide and look fo r wa rd to your fe e d b a ck .

Fred Enge l

Vice President of Engi n e e ri n g

C o n c o rd Commu n i c a t i o n s

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Th e Po c ke t Ne tw or k M an a ge m en t Su r vi va l G ui de

C o n c o r d C o m m u n i c a t i o n s , I n c .

An o ther Forewa r d

C o n c o rd Communications has undert a ken an ambitious

and va l u able project with this handbook. I have rev i ewe d

i t ,made suggestions and tried to make certain that we

o ffer the most objective and clear descriptions of the

t e rm s .

We have wo rked to provide concise and self-contained

d e s c riptions whenever possibl e . Of cours e ,some things

depend on other defi n i t i o n s ,w h i ch are noted and fo u n d

in the glossary.

We also have attempted to gi ve the book a longer life t i m e

for you by including descriptions of new ly emerging tech￾n o l o gies and services when appro p ri a t e .

This project will have been a success if, when I visit yo u r

o ffi c e , I see a dog-eare d ,c o ffee-stained handbook. As yo u

use this handbook, keep in mind that we welcome any

fe e d b a ck — let us know what is helpful and what needs

adjusting to increase its value for yo u .

John McConnell

P re s i d e n t , McConnell Consulting,I n c .

C o n c o r d C o m m u n i c a t i o n s , I n c . 5

Th e Po c ke t Ne tw o r k Man a ge m en t Su r vi va l G ui d e

SECTION 1: NETWO R KING TEC H N O LO GI ES

Part 1: Wi de Area Te c h n o lo gi es

A. OVE RVI E W

Wide A rea tech n o l o gies enable connectivity across an

unlimited ge o graphic span. Wide A rea tech n o l o gies are

supplied by public carri e rs ,s u ch as the telephone com￾p a ny, or companies can obtain the basic facilities from the

c a rri e rs and provide their own pri vate Wide A rea serv i c e s .

Wide A rea Netwo rks are ch a ra c t e rized by two key attri b -

u t e s :(1) the bandwidth is re l a t i ve ly lower than that fo r

Local A rea Netwo rk s ; and (2) they are ex p e n s i ve .U s u a l ly

Wide A rea Netwo rks comprise a monthly bill — either a

flat rate or usage-based ch a rge s .T h u s ,Wide A rea Netwo rk s

a re the slowe s t , most ex p e n s i ve parts of the netwo rk .

Wide A rea links tend to be more ex p e n s i ve than virtual

c i rcuits because they re s e rve the full capacity of the Wi d e

A rea link. S h a red tech n o l o gies such as Frame Relay do not

dedicate the bandwidth and thus are ch e a p e r. If full capac￾ity is re q u i red at all times,Wide A rea links provide an

excellent solution.

Vi r t ual Circuits

Vi rtual circuits behave as if they are a hard - w i red

p hysical connection between two points. T h e re may be

s eve ral virtual circuits on a single physical wire . As a user,

it appears that your virtual circuit dire c t ly connects Los

A n geles and New Yo rk . In actuality,the connection may

run through intermediate points such as Phoenix,D a l l a s ,

and Wa s h i n g t o n .

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Th e Po c ke t Ne twor k Man a ge m en t Su r vi va l G u i d e

C o n c o r d C o m m u n i c a t i o n s , I n c .

If there is a fa i l u re in the existing path,an altern a t e

P h o e n i x - t o - D e nve r - t o - N ew Yo rk route may be ava i l able if

t h e re are other paths. In contra s t , a fa i l u re in a dedicated

p hysical circuit interrupts serv i c e . Vi rtual circuits are

often re - routed when there are fa i l u res in the ori gi n a l

p a t h . Those ch a n ges may cause delays because the pack￾ets have to go through more hops.

Fi g u re 1: Vi rtual circuits connect two or more points on the

e d ge of the netwo rk “ cl o u d .” From the subscri b e r ’s pers p e c t i ve a

v i rtual circuit behaves as if there is a physical connection

b e t ween the points, although there usually isn’t .

T h e re are two types of virtual circ u i t s : p e rmanent and

sw i t ch e d .

PV Cs and SV Cs

Pe rmanent Vi rtual Circuits (PVCs) are always “ i n - p l a c e ”

and re a dy to use. T h ey are meant for high-vo l u m e ,h i g h -

d u ration usage and may be set up to fo l l ow a specifi c

p a t h . In contra s t ,S w i t ched Vi rtual Circuits (SVCs) are

l i ke making a phone call — the circuit is cre a t e d ,u s e d ,

and torn down on an as-needed basis. Although there is a

C o n c o r d C o m m u n i c a t i o n s , I n c . 7

Th e Po c ke t Ne tw o r k Man a ge m en t Su r vi va l G ui de

Source:

McConnell Consulting, Inc.