[G. Cooperman, E. Jessen, G. Michler (Auth.), (BookZa.org)

8/12/2019 [G. Cooperman, E. Jessen, G. Michler (Auth.), (BookZa.org)

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impor t an t s ec t i on o f t h i s workshop was devo t ed t o r epo r t s abou t ex i s t i ngg igab i t t e s t beds and p l anned h igh speed ne tworks i n t he Un i t ed S t a t es ,Europe , and i n pa r t i cu la r i n Ge rma ny . Th ese t e s tbeds i nc lude : t he Am er i canin i ti a t ives fo r t he nex t genera t ion in t e rne t NG I) an d t he In t e rne t 2 o f abou t120 Un iver s i ti e s in t he Un i t ed S ta t es c f . K . A bda l i ) ; t he Norw eg ian N a t i ona lR e s e a r c h N e t w o r k c f. T . P l a g e m a n n ) ; a n d th e p l a n n e d G e r m a nGigab i twi s senschaf t sne t z GW in) c f . E . J es sen ) .The N GI i n it ia t i ve i s f i nanc i a l l y suppor t ed by t he A me r i can f ede ra l agenc i esD A R P A , D O E , N A S A , N I H , N I S T a n d N S F . I t a im s :a ) t o p r o m o t e r e se a r ch , d e v e l o p m e n t a n d e x p e r i m e n t a t i o n i n a d v a n c e d

n e t w o r k i n gt echno log i es ;b ) t o d e p l o y a N G I t e s tb e d e m p h a s i z i n g e n d - to - e n d p e r f o r m a n c e , e n d - t o - e n dq u a l it y o fse rv i ce and s ecu r i ty ;c ) t o deve lop u l t r a h igh speed sw i t ch ing and t r ansmi s s ion t echno log i es ;d ) t o d e v e l o p d e m a n d i n g a p p l ic a ti o n s th a t m a k e u s e o f t h e a d v a n c e s i nn e t w o r kt echno log i es . A m on g t he p roposed a pp l i ca ti on a reas a re : hea l t h ca re , c r is i sm a n a g e m e n tand response , d i s t ance l ea rn ing , and d i s t ri bu t ed h igh pe r fo rm anc ecomputa t i ons fo rb iomed ic ine , c l ima t e m ode l i ng , and bas i c s c i ence .The In t e rne t 2 p ro j ec t i s funded by 77 Amer i can un ive r s i t i e s and someindus t r ia l par tners . I t i s dr iven by educat ion and research . In ternet 2 wi l li nc lude a g igab i t ne two rk P ro j ec t Ab i l ene ) , wh ich w i ll opera t e i n 1999 . O fcourse i t w i ll benef i t f rom the exp er imen t s an d resu l t s o f t he N G I i n i ti a t ive .I n G e r m a n y , i n s p r in g 2 0 0 0, G W i n , t h e g ig a b i t n e t w o r k o f D F N D e u t s c h e sF orschun gsne t z ; Germ an n a t i ona l s c i en t if i c ne two rk ing as soc i a t i on ) w i ll s t a r ti t s opera t ion .As a fo re runner fo r i t s g igab i t ne twork , DF N i s suppor t i ng two g igab i tt e s tbeds in W es t and S ou th Germ any wi th a l i nk t o Ber l i n ) whe reexper imen t s a re pe r fo rmed . S evera l a r t i c l e s o f t h i s vo lume repor t bo th onp l a n n e d a n d o n c o m p l e t e d e x p e r i m e n t s . T h e g i g a b i t t e s t b e d W e s t c o n n e c t st he r esea rch cen t e r s GMD S t . Augus t i n and F Z J t i l i ch i n Nor th Rh ineW es tpha l i a wi th a bandwid th o f 2 . 5 Gbps . I t has b roadband connec t i ons t ot h e c o m p u t e r c e n te r s o f t h e D L R D e u t s c h e s Z e n t r u m f u r L u f t - u n dR a u m f a h r t) in C o l o g n e - P o r z a n d t h e U n i v e r s it ie s o f C o l o g n e a n d E s s e n . T h eg igab i t t e s t bed S t i d connec t s t he Un iver s i t y o f E r l angen and t he Techn i ca lUn iver s i t y o f Mun ich . I t cu r ren t l y cons i s t s o f a da rk f i be r connec t i onb e t w e e n t h e c o m p u t e r c e n t e r s o f t h e s e u n i v e r s i t i e s . T h e b a n d w i d t h o f t h i sswi t ched AT M ne tw ork is i n i ti a l ly 3 times 2 .5 G bps , and has a capac i t y m an yt imes l a rge r t h rough t he use o f wave l eng th d iv i s i on mul t i p l ex ing . The


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g igab i t t e s t b ed S Od wi l l be e x t ended t o B er l i n an d S tu t tga r t , i n o rde r t oconnec t t he supercompu te r s a t t he Konrad Zuse Ins t i t u t e i n Ber l i n , Le ibn i zC o m p u t i n g C e n t e r i n M u n i c h a n d t h e C o m p u t i n g C e n t e r o f S t u t t g a r tUn iver s i t y . Th i s wide a rea ne twork o f supercompu te r s wi l l be u sed fo rd e m a n d i n g d i s t r i b u t e d h i g h p e r f o r m a n c e c o m p u t a t i o n s i n a p p l i e dm a t h e m a t i c s , p h y s i c s, c h e m i s t r y , e n g i n e e r in g , e c o n o m i c s a n d m e d i c i n e .In 1997 t he Un i t ed S t a tes has e s t ab l i shed the Na t i ona l Co m puta t i on a l S c i enc eAl l i ance . I t i s l ed by t he S upercompu te r Cen t e r s a t t he Un iver s i t y o f I l l i no i sa t U r b a n a a n d t h e U n i v e r s i t y o f C a l i f o r n i a a t S a n D i e g o . E a c h a l l i a n c econs i s t s o f more t han 60 pa r t ne r i n s t i t u t i ons , i nc lud ing academic andgovernmen t r e sea rch l abs and i ndus t r i a l o rgan i za t i ons . These coopera t i ngi n s t i t u t i o n s a l l b e n e f i t f r o m a m e t a c o m p u t i n g e n v i r o n m e n t b a s e d o n h i g hspeed ne tworks . K . Abda l i o f t he NS F p rov ides fu r t he r de t a i l s i n t he a r t i c l e ,A d v a n c e d c o m p u t i n g a n d c o m m u n i c a t i o n s r e s e ar c h u n d e r N S F s u p p o r t .The s t r i c t e s t r equ i remen t s fo r h igh bandwid th app l i ca t i ons can cu r ren t l y bef o u n d i n t h e a r e a s o f m e t a c o m p u t i n g a n d d i s t r i b u t e d h i g h p e r f o r m a n c ecomputa t i on . These app l i ca t i ons s e rve a s econdary pu rpose i n s t r e s s t e s t i ngthe ne twork , t o he lp t he eng inee r s and co m pu te r s c i en ti s ts des ign be t t e r ones .However , t he number o f such l a rge s ca l e exper imen t s i s cu r ren t l y r a the rsmal l . As l ong as t he coopera t i ng i n s t i t u t i ons i n t e rconnec t ed by a wide a reah igh speed ne twork a re no t g iven ex t ra r e sou rces fo r d i s t r i bu t ed compu te rappl ica t ion s th i s s i tuat ion i s l ike ly to cont inu e.Ano ther s e t o f l ec tu res a t t he mee t i ng was devo t ed t o t he i n t e rp l ay be tweenc o m m u n i c a t i o n h a r d w a r e a n d s o f t w a r e f o r h i g h s p e e d c o m p u t e r n e t w o r k sa n d m a t h e m a t i c a l a l g o r i t h m d e v e l o p m e n t f o r d i s t r i b u t e d h i g h p e r f o r m a n c ecom puta t i ons . In pa r ti cu la r , t he imp lem en ta t i ons o f t he pa ra l l e l l i nea r a l geb raa l g o r it h m s h e l p t o c r e a te e x p e r i m e n t s c h e c k i n g t h e t e c h n i c a l c o m m u n i c a t i o np r o p e rt ie s o f a b r o a d b a n d c o m p u t e r n e t w o r k w i t h 1 55 M b i t/ s b a n d w i d t h a n dh igher . On t he o the r s i de such benchmarks a l so he lp t o ana lyze t hee f f f i c i en cy o f a ma themat i ca l a l go r it hm.Th i s vo lume a l so con t a ins s evera l con t r i bu t i ons concern ing t he ve ryo rgan i za t i on o f s c i en t i f i c knowledge , i t s e l f . Many sc i en t i f i c pub l i ca t i onsq u o t i n g h i g h p e r f o r m a n c e c o m p u t e r a p p li c a ti o n s l a c k p r o p e r d o c u m e n t a t i o no f t h e o r ig i n a l c o m p u t e r p r o g r a m s a n d o f t h e m e m o r y i n t e n s i v e o u t p u t d a t a .R e c e n t l y m a n y m a t h e m a t ic a l a n d o t h e r s c i e n ti f ic j o u r n a l s h a v e b e g u nof fe r i ng bo th paper and d ig i ta l fo rmat s . The d ig i ta l ve r s i ons o f fe r m an yadvan t ages fo r t he fu tu re . They have t he po t en t i a l fo r be ing s ea rched , andthey can be i nco rpo ra t ed i n to a d i s t r i bu t ed l i b ra ry sys t em. Over s c i en t i f i cw i d e a r e a n e t w o r k s s u c h a s t h e p l a n n e d G e r m a n G i g a b i t w i s s e n s c h a f t s n e t z ,l i b ra r i e s o f un ive r s i t i e s and resea rch i n s t i t u t es i n d ig i t a l fo rm can becombined i n to a na t i ona l d i s t r i bu t ed r esea rch l i b ra ry . The members o f t heseins t it u t ions can be a l l owed t o s ea rch , r ead , p r in t and ev en a nno t a t e t he d ig i t a lt ex t s ( and t he i r compu ta t i ona l append i ces con t a in ing t he o r i g ina l p rog rams


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d v a n c e d C o m p u t i n g a n d C o m m u n i c a t i o n sR e s e a r c hu n d e r N S F S u p p o r tS . K a m a l A b d a l iNa t iona l Sc ience Fou nda t ion , A r l ing ton , VA 22230, USA

A b s t r a c t . T h i s p a p e r d isc us ses t h e re s e ar c h i n it ia t iv e s a n d p r o g r a m s s u p p o r t e db y t h e N a t i o n a l S c i e n c e F o u n d a t i o n t o p r o m o t e h i g h - e n d c o m p u t i n g a n d l a r g e -sc a l e ne twor k ing . Th i s wor k ma in ly f a l l s unde r t he US in t e r a ge nc y a c tv i ty c a l l e dH i g h P e r f o r m a n c e C o m p u t i n g a n d C o m m u n i c a t i o n s H P C C ) . T h e p a p e r d es c ri b e st h e F e d e r al g e o v e r n m e n t c o n t e x t o f H P C C , a n d t h e H P C C p r o g r a m s a n d t h e i rma in a c c ompl i she m nt s . F inal ly , i t de c r ibe s t he r e c om m e nd a t ions o f a r e c e n t h i g hl eve l a dv i so r y c ommi t t e e on in f o r ma t ion t e c hno logy , a s t he se a r e l i ke ly t o ha ve am a j o r i m p a c t o n t h e f u t u r e o f g o v e r n m e n t i n it ia t iv e s i n h i g h -e n d c o m p u t i n g a n dne tworking .

I n t r o d u c t i o nA p r e v i o u s p a p e r [1] d e s c r i b e d t h e a c t i v it i e s o f t h e N a t i o n a l S c i e n c e F o u n -d a t i o n N S F ) in t h e U .S . H i g h P e r f o r m a n c e C o m p u t i n g a n d C o m m u n i c a -t i o n s H P C C ) p r o g r a m u n t il 1 9 96 . T h e p u r p o s e o f t h e p r e s e n t p a p e r is t ou p d a t e t h a t d e s c r i p t io n t o c o v er t h e d e v e l o p m e n t s si nc e th e n . W h i le s o m em a n a g e m e n t c h a n ge s h a v e t a k e n p l a c e d u r i n g t h is p e r i o d , a n d t h e r e i s s o m er e d i r e c t i o n o f i ts t h r u s t s , t h e H P C C p r o g r a m c o n t i n u e s t o f lo u r is h , t o s a yt h e l e as t . T h e m a i n n e w a c t iv i t ie s a t th e N S F a r e P a r t n e r s h i p s f o r A d v a n c e dC o m p u t i n g I n f r a s tr u c t u r e s P A C I s ), t h e N e x t G e n e r a t i o n I n t e r n e t N G I ) ,a n d t h e K n o w l e d g e a n d D i s t r i b u t e d I n t e l li g e n c e K D I ) i n i t ia t i v e , a n d t h e r ea r e re n e w e d p r o g r a m s f o r S c i en c e a n d T e c h n o l o g y C e n t e r s a n d D i g i t a l L i -b r a r ie s . N e w i n i ti a t iv e s t h a t m a y r e p l a c e t h e p r o g r a m o r c h a n g e i ts d i r e c t i o ns u b s t a n t i a l l y a r e a ls o e x p e c t e d t o r e s u l t f ro m t h e r e c o m m e n d a t i o n s o f t h eP r e s i d e n ti a l I n f o r m a t i o n T e c h n o l o g y A d v i s o r y C o m m i t t e e P I T A C ) . T h e p a -p e r i s m a i n l y c o n c e r n e d w i t h t h e s e n e w i ss u es . B u t t o m a k e i t s e l f - c o n t a i n e d ,t h e e n t i r e H P C C c o n t e x t i s b r i ef l y d e s c r i b e d a l so .

2 T h e H P C C p r o g r a mT h e U S H i gh P e r f o r m a n c e C o m p u t i n g a n d C o m m u n i c a t io n H P C C ) p r o g r a mw a s la u n c h e d i n 1 99 1. I t o p e r a t e d a s a c o n g r e s s i o n a l ly m a n d a t e d i n i t i a t iv ef ro m O c t o b e r 1 99 1 t h r o u g h S e p t e m b e r 1 99 6, f ol lo w i ng t h e e n a c t m e n t o f t h e


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H i g h P e r f o r m a n c e C o m p u t i n g A c t o f 19 91 . S in c e O c t o b e r 1 9 96 , i t h a s c o n -t i n u e d a s a p r o g r a m u n d e r t h e l e a d e r sh i p o f t h e C o m p u t i n g , I n f o r m a t i o n ,a n d C o m m u n i c a t i o n s ( C IC ) S u b c o m m i t t e e o f t h e C o m m i t t e e on T e c h n o lo g y( C T ) w h i c h is i ts e l f o v e r se e n b y t h e N a t i o n a l S c ie n c e a n d T e c h n o l o g y C o u n -c il, a U S C a b i n e t - l e v e l o r g a n i z a t i o n . I n s t r u m e n t a l i n t h e e s t a b l i s h m e n t o f t h ep r o g r a m w a s a s e r i e s o f n a t i o n a l -l e v e l s t u d i e s o f s c ie n t if ic a n d t e c h n o l o g i -c a l t r e n d s i n c o m p u t i n g a n d n e t w o r k i n g [ 2 - 5 ] . T h e s e s t u d i e s c o n c l u d e d a n dp e r s u a s i v e l y a r g u e d t h a t a f e d e r al - le v e l i n i t i a t iv e i n h i g h - p e r f o r m a n c e c o m -p u t i n g w a s n e e d e d t o e n s u r e t h e p r e e m i n e n c e o f A m e r i c a n s c i e n c e a n d t e c h -n o l og y . S o l v i n g t h e c h a l l e n g i ng s c i e n ti fi c a n d e n g i n e e r i n g p r o b l e m s t h a t w e r ea l r e a d y o n t h e h o ri z o n re q u i r e d s ig n i fi c an t ly m o r e c o m p u t a t i o n a l p o w e r t h a nw a s a v a i l a b l e . A n o t h e r f a c t o r w a s t h e p r o g r e s s m a d e a b r o a d , e s p e c i a l l y t h eJ a p a n e s e a d v a n c e s i n s e m i c o n d u c t o r c h i p m a n u f a c t u r e a n d s u p e r c o m p u t e rd e s i g n , a n d t h e W e s t e r n E u r o p e a n a d v a n c e s i n s u p e r c o m p u t i n g a p p l i c a t i o n si n sc i e n c e a n d e n g i n e e ri n g . I t w a s a l s o c l e a r t h a t t h e a d v a n c e s i n i n f o r m a t i o nt e c h n o l o g y w o u l d h a v e a f a r r e a c h in g i m p a c t b e y o n d s c i e nc e a n d t e c h n o l o g y ,a n d w o u l d a ff ec t s o c i e ty in g e n e r a l in p r o f o u n d , u n p r e c e d e n t e d w a y s . T h eH P C C p r o g r a m w a s t h u s e s t a b l is h e d t o s t i m u l a t e , a c c e l e r a te , a n d h a r n e s st h e s e a d v a n c e s f o r c o p i n g w i t h s c i e n t i f i c a n d e n g i n e e r i n g c h a l l e n g e s , s o l v i n gs o c i e t a l a n d e n v i r o n m e n t a l p r o b l e m s , m e e t i n g n a t i o n a l s e c u r i t y n e e d s , a n di n i m p r o v i n g t h e n a t i o n s e c o n o m i c p r o d u c t i v i t y a n d c o m p e t i t i v e n e s s .

A s l a t e a s 1 99 6, t h e g o a ls o f t h e H P C C i n i ti a t iv e w e r e s t a t e d s e p a r a t e l y( e.g ., i n [1 0]) f r o m t h e C I C m i ss io n d e s c r i p ti o n s . N o w t h a t H P C C h a s b e c o m ea C I C r e s e a r c h a n d d e v e l o p m e n t (R :D ) p r o g r a m , i t s g o a l s a r e s u b s u m e d i nthe CIC goa l s , wh ich a re fo rmal ly s t a t ed as fo l lows ( [13 ] ) :

* A s s u re c o n t i n u e d U S le a d e r sh i p in c o m p u t i n g , i n f o r m a t i o n , a n d c o m m u -n i c a t i o n s t e c h n o l o g i e s t o m e e t F e d e r a l g o a l s a n d t o s u p p o r t U . S . 2 1 s tc e n t u r y a c a d e m i c , d e f e n s e , a n d i n d u s t r i a l i n t e r e s t s* A c c e l e r a t e d e p l o y m e n t o f a d v a n c e d a n d e x p e r i m e n t a l i n f o r m a t i o n t e c h -n o l o g ie s t o m a i n t a i n w o r l d l e a d e r s h i p i n s c ie n c e , e n g i n e e r i n g , a n d m a t h -e m a t i c s; i m p r o v e t h e q u a l i ty o f life ; p r o m o t e l o n g t e r m e c o n o m i c g r o w t h ;i n c r e a s e l if e lo n g l e ar n in g ; p r o t e c t t h e e n v i r o n m e n t ; h a r n e s s i n f o r m a t i o nt e c h n o l o g y ; a n d e n h a n c e n a t i o n a l s e c u r i t y* A d v a n c e U .S . p r o d u c t i v i t y a n d i n d u s t ri a l c o m p e t i t i v e n e s s t h r o u g h l o ng -t e r m s c ie n t if ic a n d e n g i n e e r i n g re s e a r c h in c o m p u t i n g , i n f o r m a t i o n , a n dc o m m u n i c a t io n s t e c hn o l o g ie s

3 H P C C P a r t i c i p a n t s a n d C o m p o n e n t sT h e H P C C p r o g r a m a t p r e s e n t i n v o l v e s 1 2 F e d e r a l a g e n c i e s , e a c h w i t h i t ss p e c if ic r e s p o n s i b il i ti e s . I n a l p h a b e t i c a l o r d e r , t h e p a r t i c i p a t i n g a g e n c i e s a r e :A g e n c y fo r H e a l t h C a r e P o li c y a n d R e s e a r c h ( A H C P R ) , D e f e ns e A d v a n c e dR e s e a rc h P r o j e c t s A g e n c y ( D A R P A ) , D e p a r t m e n t o f E n e r g y ( D O E ) , D e -p a r t m e n t o f e d u c a t i o n ( E D ) , E n v i r o n m e n t a l P r o t e c t i o n A g e n c y ( E P A ) , N a -


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t io n a l A e r o n a u t i c s a n d S p a c e A d m i n i s t r a t io n ( N A S A ) , N a t i o n a l I n s t i t u t e o fH e a l t h ( N I H ) , N a t i o n a l I n s t i t u t e o f S t a n d a r d s a n d T e c h n o l o g y ( N I S T ) , N a -t i o n a l O c e a n i c a n d A t m o s p h e r i c A d m i n i s t r a ti o n ( N O A A ) , N a t i o n a l S e c u r i t yA g e n c y (N S A ) , N a t i o n a l S c ie n c e F o u n d a t i o n ( N S F ) , a n d D e p a r t m e n t o f V e t -e r a n A f f ai rs (V A ) . T h e a c t i v i t ie s s p o n s o r e d b y t h e s e a g e n c i e s h a v e b r o a dp a r t i c i p a t i o n b y u n iv e r s i ti e s a s w e l l a s t h e i n d u s t r y . T h e p r o g r a m a c t i v i t i e so f t h e p a r t i c i p a t in g o r g a n i za t io n s a r e c o o r d i n a t e d b y t h e N a t i o n a l C o o r d i n a -t io n O f fi ce f o r C o m p u t i n g , I n f o r m a t i o n , a n d C o m m u n i c a t i o n s ( N C O ) , w h i c ha l s o s e r v e s a s t h e l i a i s o n t o t h e U S C o n g r e s s , s t a t e a n d l o c a l g o v e r n m e n t s ,f o r ei g n g o v e r n m e n t s , u n i v e rs i ti e s , i n d u s t r y , a n d t h e p u b l ic . T h e N C O d i s s e m -i n a t e s i n f o r m a t i o n a b o u t H P C C p r o g r a m a c t i v i t i e s a n d a c c o m p l i s h m e n t s i nt h e f o rm o f a n n o u n c e m e n t s , t e c h n i c a l r e p o r t s , a n d t h e a n n u a l r e p o r t s t h a t a r ep o p u l a r l y k n o w n a s b l u e b o o k s [ 6- 13 ]. T h e N C O a l s o m a i n t a i n s t h e w e bs i t e ht tp: / /ww w ccic gov o p ro v i d e u p - t o - d a te , o n l in e d o c u m e n t a t i o n a b o u tt h e H P C C p r o g r a m , a s w e ll a s l in k s to t h e H P C C - r e l a t e d w e b p a g e s o f a llp a r t i c i p a t i n g o r g a n i z a t i o n s .

T h e p r o g r a m c u r r e n t ly h a s f iv e c o m p o n e n t s : 1 ) H i g h E n d C o m p u t i n ga n d C o m p u t a t i o n , 2 ) L a r g e S ca l e N e t w o r k i n g , 3 ) H i g h C o n f i d e n c e S y s t e m s ,4 ) H u m a n C e n t e r e d S y s t e m s , a n d 5 ) E d u c a t i o n , T r a i ni n g , a n d H u m a n R e -s o u rc e s . T o g e t h e r , t h e s e c o m p o n e n t s a r e m e a n t t o f o st e r, a m o n g o t h e r t h i n g s ,s c ie n t if ic r e s e a r c h , t e c h n o l o g i c a l d e v e l o p m e n t , i n d u s t r i a l a n d c o m m e r c i a l a p -p l i c a t i o n s , g r o w t h i n e d u c a t i o n a n d h u m a n r e s o u r c e s , a n d e n h a n c e d p u b l i ca c c e s s t o i n f o r m a t i o n . I n a d d i t i o n t o t h e s e c o m p o n e n t s , t h e r e i s a F e d e r a lI n f o r m a t i o n S e r v ic e s a n d A p p l i c a t i o n s C o u n c i l t o o v e r se e t h e a p p l i c a t i o n o fC I C - d e v e l o p e d te c h n o l o g i e s f o r f e d e r a l i n f o r m a t i o n s y s t e m s , a n d t o d i s s e m i -n a t e i n f o r m a t i o n a b o u t H P C C r e s e a r c h t o o t h e r F e d e ra l ag e n c i e s n o t f o r m a l l yp a r t i c i p a t i n g i n t h e p r o g r a m .

T h e g o a l s o f t h e H P C C c o m p o n e n t s a re a s f o ll ow s ( se e t h e B l u e B o o k99 [13] for an of f ic ia l descr ip t ion ) :1. H i g h E n d C o m p u t i n g a n d C o m p u t a t i o n : T o a ss u re U S le ad er s h ip

i n c o m p u t i n g t h r o u g h i n v e s t m e n t i n le a d i n g -e d g e h a r d w a r e , s o f t w a r e ,a n d a l g o r i t h m i c i n n o v a t io n s . S o m e r e p r e s e n t a t i v e r e s e a r c h d i r e c t i o n s a r e :c o m p u t i n g d e v i c e s a n d s t o r a g e t e c h n o l o g i e s f o r h i g h - e n d c o m p u t i n g s y s -t e m s ; a d v a n c e d c o m p u t i n g a r c h i t e c t u re s ; a d v a n c e d s o f t w a r e s y s t e m s , a l-g o r i th m s , a n d s o f tw a r e f or m o d e l i n g a n d s i m u l a ti o n . T h i s c o m p o n e n ta l so s u p p o r t s i n v e s ti g a t io n o f i d e a s s u c h a s o p ti c a l, q u a n t u m , a n d b i o -m o l e c u l a r c o m p u t i n g t h a t a r e q u i t e s p e c u l a t i v e a t p r e s e n t , b u t m a y l e a dt o f e a si b le c o m p u t i n g t e c h n o l og i e s i n t h e f u t u r e , a n d m a y r a d i c a l ly c h a n g et h e n a t u r e o f c o m p u t i n g .

2 . L a r g e S c a l e N e t w o r k i n g : T o a s s u re U S l e ad e r sh i p in h i g h - p e r fo r m a n c ec o m m u n i c a t io n s . T h i s c o m p o n e n t s e ek s t o im p r o v e t h e s t a t e - o f - t h e - a r ti n c o m m u n i c a t i o n s b y i n v e st in g i n re s e a r c h o n n e t w o r k i n g c o m p o n e n t s ,s y s t e m s , s e rv i ce s , a n d m a n a g e m e n t . T h e s u p p o r t e d r e s e a r c h d i r e c t i o n si n c l u d e : a d v a n c e d t e c h n o l o g i e s t h a t e n a b l e w i r e l e s s , o p t i c a l , m o b i l e , a n d


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wireline communications; large-scale network engineering; system soft-ware and program development environments for network-centric com-puting; and software technology for distributed applications, such as elec-tronic commerce, digital libraries, and health care delivery.3. Hi gh Co nf id en ce Sy st em s: To develop technologies that provide userswith high levels of security, protection of privacy and data, reliability, andrestorability of information services. The supported research directionsinclude: system reliability issues, such as network management underoverload, component failure, and intrusion; survival of threatened systemsby adaptat ion and reconfiguration; technologies for security and privacyassurance, such as access control, authentication, and encryption.4. Human C e n t e r e d S y s t e m s : To make computing and networking moreaccessible and useful in the workplace, school, and home. The technolo-gies enabling this include: knowledge repositories and servers; collabora-tories that provide access to information repositories and that facilitatesharing knowledge and control of instruments at remote labs; systemsthat allow multi-modal human- system interactions; and virtual realityenvironments and their applications in science, industry, hea lth care, andeducation.5. E d u c a t i o n T r a i n i n g a n d H u m a n R e s o u r c e s: To support HPCC re-search tha t enables modern education and training technologies. All lev-els and modes of education are targeted, including elementary, secondary,vocational, technical, undergraduate, graduate, and career-enhancing ed-ucation. The education and training also includes the production of re-searchers in HPCC technologies and applications, and a skilled workforceable to cope with the demands of the information age. The supportedresearch directions include information-based learning tools, technologiesthat support lifelong and distance learning for people in remote locations,and curriculum development.

H P C C a t N S FAs mentioned above, NSF is one of the 12 Federal agencies participatingin the HPCC program. The total HPCC budget and the NSF share in itsince the inception of the program are shown in Table 1. Thus, during thisperiod, NSF's share has ranged approximately between one-fourth and one-third of the total Federal HPCC spending. The HPCC amount has remainedapproximately 10% of the NSF's own total budget during the same period.

Table 1. HPCC Investment: Total budget and NSF's share (in M)Fiscal Year 1992 1993 1994 1995 1996 1997 1998 1999Total HPCC budget 655 803 938 1039 1043 1009 1070 830NSF's HPCC share 201 262 267 297 291 280 284 297


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T h e N S F o b j e c t i v e s f or i ts H P C C e f fo r t a re :9 E n a b l e U . S . t o u p h o l d a p o s i t i o n o f w o r l d l e a d e r s h i p i n t h e s c i e n c e a n d

e n g i n e er in g o f c o m p u t i n g , i n f o r m a t i o n a n d c o m m u n i c a t i o n s .9 P r o m o t e u n d e r s t a n d i n g o f t h e p r i nc i p le s a n d u s e s o f a d v a n c e d c o m p u t -i ng , c o m m u n i c a t io n s , a n d i n f o r m a t i o n s y s t e m s in s e r v i c e t o s c ie n c e a n de n g i n e e r i n g , t o e d u c a t i o n , a n d t o s o c i e t y .

9 C o n t r i b u t e t o u n iv e r sa l, t r a n s p a r e n t , a n d a f f o r d a b le p a r t i c i p a t i o n i n a ni n f o r m a t i o n - b a s e d s o c i e t y .T h u s N S F ' s H P C C - r e l a t e d w o r k sp a n s a c r os s a ll o f t h e f iv e H P C C p r o g r a mc o m p o n e n t s .

H P C C r e s e a r c h p e n e t r a t e s t o v a r y i n g d e p t h n e a r l y a l l t h e s c i e n t i f i c a n de n g i n e e r i n g d is c ip l in e s a t N S F . B u t m o s t o f t h i s r e s e a r c h i s c o n c e n t r a t e di n t h e N S F ' s D i r e c t o r a t e o f C o m p u t e r a n d I n f o r m a t i o n S c i en c e a n d E n g i -n e e r i n g ( C I S E ) . T h i s d i r e c t o r a t e i s o r g a n i z e d i n t o 5 divisions e a c h o f w h ic hi s , in tu rn , d iv ided in to 2 -8 programs T h e w o r k o f t h e C I S E d i v is i on s c a nb e , r e s p e c t i v e l y , c h a r a c t e r i z e d a s : f u n d a m e n t a l c o m p u t a t i o n a n d c o m m u n i -c a t i o n s r e s e a r c h ; i n f o r m a t i o n , k n o w l e d g e , i n t e l l i g e n t s y s t e m s , a n d r o b o t i c sr e s e a rc h ; e x p e r i m e n t a l s y s t e m s r e s e a r c h a n d i n t e g r a t i v e a c t i v i t i e s ; a d v a n c e dc o m p u t a t i o n a l i n f r a s t r u c t u r e r e s e a r c h ; a n d a d v a n c e d n e t w o r k i n g i n f r a s t r u c -t u r e r e se a r ch . W h i le t h e p h r a s e " h ig h p e r fo r m a n c e " m a y n o t b e e x p l ic i t lyp r e s e n t i n th e d e s c r i p t io n o f m a n y p r o g r a m s , t h e a c t u a l r e s e a r c h t h e y u n -d e r t a k e i s v e r y m u c h f o c u s e d o n H P C C . I n d e e d , t h e C I S E b u d g e t i s a l m o s te n t ir e ly a t t r i b u t e d t o H P C C . R e p r e s e n t a t i v e o n g o i ng r e s e a rc h t o p i c s in c lu d e :s c a l a b l e p a r a l l e l a r c h i t e c t u r e s ; c o m p o n e n t t e c h n o l o g i e s f o r H P C C ; s i m u l a -t i o n , a n a l y s i s , d e s i g n a n d t e s t t o o l s n e e d e d f o r H P C C c i r c u i t a n d s y s t e md e s ig n ; p a r a l le l s o f t w a r e s y s t e m s a n d t o o l s , s u c h a s c o m p i l e r s , d e b u g g e r s ,p e r f o r m a n c e m o n i t o r s , p r o g r a m d e v e l o p m e n t e n v i r o n m e n t s ; h e t e r o g e n e o u sc o m p u t i n g e n v i r o n m e n t s ; d i s t r i b u t e d o p e r a t i n g s y s t e m s , t o o l s f o r b u i l d i n gd i s t r i b u t e d a p p l i ca t io n s ; n e t w o r k m a n a g e m e n t , a u t h e n t i c a t i o n , s e c u ri ty , a n dr e l ia b i l it y ; in t e ll i g e n t m a n u f a c t u r i n g ; i n t el l ig e n t l e a r n i n g s y s t e m s ; p r o b l e ms o lv i n g e n v i r o n m e n t s ; a l g o r i th m s a n d s o f t w a r e fo r c o m p u t a t i o n a l s c ie n c e a n de n g i n ee r in g ; i n t e g r a t i o n o f r e s e a r c h a n d l e a r n i n g t e c h n o l o g i e s ; v e r y l a rg e d a t aa n d k n o w l e d g e b a s e s ; v i s u a l i z a t io n o f v e r y la r g e d a t a s e t s .

5 L a r g e H P C C P r o j e c t sT h e H P C C p r o g r a m h a s l e d t o se v e r al i n n o v a t io n s i n N S F ' s m e c h a n i s m sf o r s u p p o r t i n g r e s e a rc h a n d h u m a n r e s o u r c e s d e v e l o p m e n t . T h e t r a d i t i o n a lm a n n e r o f f u n d i n g i n d i v id u a l r e s e a r c h e rs o r s m a l l r e s e a rc h t e a m s c o n t i n u e st o b e a p p li e d fo r H P C C w o r k t o o. B u t t o m e e t s p e c ia l H P C C n e e d s, N S Fh a s i n i ti a t e d a n u m b e r o f t o t a l l y n e w p r o g r a m s , s u c h a s s u p e r c o m p u t i n g c e n -t e rs , p a r t n e r s h i p s f o r a d v a n c e d c o m p u t a t i o n a l i n f r a s t ru c t u r e s , s c ie n c e a n d


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10t e c h n o l o g y c e n t e r s , a n d v a r i o u s c h a l l e n g e s . A l s o l a u n c h e d w e r e s p e c i a l in i -t i a t i v e s s u c h a s d i g i t a l l i b r a r i e s , k n o w l e d g e a n d d i s t r i b u t e d i n t e l l i g e n c e , a n dt h e n e x t g e n e r a t i o n i n t e r n e t . T h e s e p r o j e c t s a r e m u c h l a r g e r t h a n t h e t r a -d i ti o n al o n e s in t h e s c o p e o f r e s ea r c h , n u m b e r o f p a r t i c i p a t i n g i n v e s t i g a t o r s ,r e s e a r c h d u r a t i o n , a n d a w a r d s i z e .5 .1 S c i en c e a n d T e c h n o l o g y C e n t e r s S T C s )T h e p u r p o s e, s t ru c t u r e , a n d H P C C c o n t r i b u ti o n s o f S T C s w e r e d e s c r i b e d in[1]. S o h e r e w e m a i n l y s t a t e t h e d e v e l o p m e n t s t h a t h a v e t a k e n p l a c e s in c e .

S T C s a r e i n t e n d e d t o s t i m u l a t e i n t e g r a ti v e c o n d u c t o f r e s e a rc h , e d u c a -t io n , a n d k n o w l e d g e t r a n sf e r . T h e y p r o v i d e a n e n v i r o n m e n t f o r i n t e r a c t i o na m o n g r e s e a r c h e r s i n v a r i o u s d i s c i p l i n e s a n d a c r o s s i n s t i t u t i o n a l b o u n d a r i e s .T h e y a l so p r o v i d e t h e s t r u c t u r e t o i d e n t if y i m p o r t a n t c o m p l e x s c ie n ti fi c p r o b -l e m s b e y o n d d is c i p l in a r y a n d i n s t i t u t i o n a l l i m i t s a n d s c a l e s , a n d t h e c r i t i c a lm a s s a n d f u n d i n g s t a b i l i t y a n d d u r a t i o n n e e d e d f o r t h e i r s u c c e s s f u l s o l u ti o n .T h e y c a r r y o u t f u n d a m e n t a l r e s ea r c h , f a c il i ta t e r e s e a r c h a p p l i c a t i o n s , p r o -m o t e t e c h n o l o g y t r a n s f e r t h r o u g h i n d u s t r i a l a f fi li a ti o n s , d i s s e m i n a t e k n o w l -e d g e v ia v is it o rs h ip s , c o n f e re n c e s a n d w o r k s h o p s , e d u c a t e a n d t r a i n p e o p l e f o rs c ie n ti fi c p r o fe s s io n s , a n d i n t r o d u c e m i n o r i t i e s a n d u n d e r r e p r e s e n t e d g r o u p st o s ci e n ce a n d t e c h n o l o g y t h r o u g h o u t r e a c h a c t i v i t ie s .

S T C s a r e l a r g e re s e a rc h p r o j e c t s e a c h o f w h i c h i n v o l v e s t y p i c a l l y 5 0 +p r i n c i p a l i n v e s t i g a t o r s f r o m 1 0 + a c a d e m i c i n s t i t u t i o n s , a n d a l s o h a s l i n k st o t h e in d u s tr y . T h e p a r t i c ip a n t s w o r k t o g e t h e r o n i n t e r d i s c i p li n a r y r e s e a r c hu n i f i e d b y a s i n g l e t h e m e , s u c h a s p a r a l l e l c o m p u t i n g o r c o m p u t e r g r a p h i c s .T h e p r o j e c t s a r e a w a r d e d i n i t i a l l y f o r 5 y e a r s , a r e r e n e w a b l e f o r a n o t h e r 5y e a r s , a n d a r e f i n a l l y g i v e n a n e x t r a y e a r f o r o r d e r l y p h a s e o u t . T h e r e i s n of u r t h e r r e n e w a l , s o a c e n t e r h a s t o s h u t d o w n d e f i n i t e l y i n a t m o s t 1 1 y e a r s .O f c o u rs e , t h e i n v e s t ig a t o r s a r e fr e e t o r e g r o u p a n d c o m p e t e a g a i n i n t h ep r o g r a m i n t h e f u t u r e i f i t c o n t i n u e s .

A s a r e s u lt o f t h e c o m p e t i t io n s t h a t t o o k p l a c e in 1 9 8 9 a n d 1 9 91 , 25 S T C sw e r e e s t ab l i sh e d b y N S F . A l l o f t h e m h a v e e n t e r e d t h e i r f i na l y e a r n o w . T h ef ol lo w in g f o u r o f t h o s e S T C s w e r e s u p p o r t e d b y t h e H P C C p r o g r a m : T h e C e n -t e r f or R e s e a r c h i n P a r a l le l C o m p u t a t i o n ( C R P C ) a t R i c e U n i v e r s i t y ; T h eC e n t e r f o r C o m p u t e r G r a p h i c s a n d S c i e n t i f i c V i s u a l i z a t i o n a t t h e U n i v e r s i t yo f U t a h ; T h e C e n te r fo r D i sc r et e M a t h e m a t i c s a n d T h e o r e t i c a l C o m p u t e rS c ie n ce ( D IM A C S ) a t R u t g e r s U n i v e r si ty ; a n d T h e C e n t e r f o r C o g n i t iv e S c i-e n c e a t t h e U n i v e r s it y o f P e n n s y l v a n i a . T h e s e S T C s h a v e c o n t r i b u t e d n u -m e r o u s t h e o r e ti c a l re s u lt s , a l g o r it h m s , m a t h e m a t i c a l a n d c o m p u t e r s c ie n c et e c h n iq u e s , li b ra r ie s , s o f tw a r e t o o l s , l a n g u a g e s , a n d e n v i r o n m e n t s . T h e y h a v ea l so m a d e s ig n i fi c an t a d v a n c e s i n v a r i o u s s c i en t i fi c a n d e n g i n e e r i n g a p p l i c a -t i o n a r e a s . T h e i r o u t p u t h a s b e e n i m p r e s s i v e i n q u a l i t y , q u a n t i t y , a n d i m p a c t .

I n 19 95 , N S F u n d e r t o o k a t h o r o u g h e v a l u a t i o n o f t h e S T C p r o g r a m . F o ro n e s t u d y [1 4], A b t A s s o c i a t e s , a p r i v a t e b u s i n e s s a n d p o l i c y c o n s u l t i n g f i r mw a s c o m m i ss io n e d to c o l le c t v a r io u s k i n d o f i n f o r m a t i o n a b o u t t h e S T C s , a n d


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11the National Academy of Science was asked to examine th at da ta and evaluatethe program. Another study [15] was conducted by the National Academyof Public Administration. Both studies concluded that the STC programrepresented excellent return on federal research dollar investment, and rec-ommended tha t the program be continued further. The studies also endorsedmost of the past guidelines regarding the funding level, award duration, em-phasis on education and knowledge transfer (additionally to research), reviewand evaluation criteria, and management structure.Based on these findings, NSF has decided to continue the STC program.A new round of proposal solicitations took place in 1998. The submi ttedproposal have been evaluated, and the awards are expected to be announcedsoon (as of March 1999).5 .2 P a r t n e r s h i p s fo r A d v a n c e d C o m p u t a t i o n a l I n f r a s t r u c t u r e s

P A C I s )The precursor to PACIs was a program called Supercomputing Ce nters SC s)that was established by NSF in 1985 even before the start of the HPCC ini-tiative. But the SC program greatly contributed to the momentum behindHPCC, and, since its launch, became a significant part of the initiative. Fora 10-year duration, the program funded four SCs: Cornell Theory Center,Cornell University; National Center for Supercomputing Applications, Uni-versity of Illinois at Urbana-Champaign; Pit tsburgh Supercomputer Center,University of Pittsburgh; and San Diego Supercomputer Center, Universityof California-San Diego. Several of their accomplishments and HPCC contri-butions have been reported in [1].

A Task Force to evaluate the effectiveness of the SC program was com-missioned by NSF in 1995. This resulted in a document which is popularlyknown as the Hayes Report [16]. The s tudy considered the al ternat ives ofrenewing the SCs or having a new competition, and recommended the latter.For a more effective national computing infrastructure development, it alsorecommended funding fewer but larger alliances of research and experimen-tal facilities and national and regional high- performance computing centers.Based on these findings, NSF instituted the PACI program in 1996, as thesuccessor to the SC program. The aim of the PACIs is to help maintain USworld leadership in computational science and engineering by providing ac-cess nationwide to advanced computational resources, promoting early useof experimental and emerging HPCC technologies, creating HPCC softwaresystems and tools, and training a high quality, HPCC-capable workforce.After holding a competition, NSF made two PACI awards in 1997. Theseare the National Computational Science Alliance (Alliance) led by the Na-tional Center for Supercomputing Applications (NCSA) at the University ofIllinois at Urbana-Champaign, and the National Partnership for AdvancedComputational Infrastructure (NPACI) led by the San Diego SupercomputerCenter at the University of California at San Diego. Each consists of more


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12than 60 partner institutions, including academic and government researchlabs, national, state-level and local computing centers, and business and in-dustrial organizations. The leading sites, which maintain a variety of high-performance computer systems, and the partners which maintain smallerconfigurations of similar systems, jointly cons titute a metacomputing envi-ronment connected via high-speed networks. The partners contribute to theinfrastructure by developing in-house, using, and testing the necessary soft-ware, tools, environments, applications, algorithms, and libraries, therebycontributing to the further growth of a national grid of networked high-performance computers.

The initial mission of the SCs was to satisfy the supercomputing needsof US computational scientists and engineers. The major role of the PACIscontinues to be to provide supercomputing access to the research communityin all branches of science and engineering. But their expanded mission putsa heavy emphasis on education and training at all levels.

5 .3 N e x t G e n e r a t i o n I n te r n e t N G I )The NGI initiative, a multi-agency Federal R&D program that began in Oc-tober 1997, is the main focus of LSN. It represents consolidat ion and refine-ment of ideas behind the vision of a National Information Infrastructure.This infrastructure is a subject of various studies, most importantly [17,18].The NGI initiative supports foundational work to lead to much more pow-erful and versatile networks than the present-day Internet. To advance thiswork, the initiative fosters partnerships among universities, industry and thegovernment. The participating federal government agencies include: DARPA,DOE, NASA, NIH, NIST and NSF. The NGI goals are:1. Promote research, development, and experimenta tion in networking tech-

nologies.2. Deploy testbeds for systems scale testing of technologies and services.3. Develop revolutionary applications that utilize the advancements innetwork technologies and exercise the testbeds.

The aim of the advancement stipulated in Goal 1 is to dramatically im-prove the performance of networks in reliability, security, quality of ser-vice/differentiation of service, and network management. Two testbeds areplanned for Goal 2. The first testbed is required to connect at least 100 sitesand deliver speeds that are at least 100 times faster end-to-end than thepresent-day Internet. The second testbed is required to connect about 10sites with end-to-end performance speed faster than the present Internet byat least a factor of 1000. The revolutionary applications called for in Goal3 are to range over enabling applications technologies as well as disciplinaryapplications. Suggested examples of the former include collaboration tech-nologies, digital libraries, distributed computing, virtual reality, and remote


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13o p e r a t i o n a n d s i m u l a t i o n . S u g g e s t e d a p p l i c a t i o n a r e a s f o r th e l a t ter i n c l u d eb a s i c s c i e n c e , e d u c a t i o n , h e a l t h c a r e , m a n u f a c t u r i n g , e l e c t r o n i c c o m m e r c e ,a n d g o v e r n m e n t i n f o r m a t i o n s e r v i c e s .

T h e N G I w o r k in p r o g r e ss w a s s h o w c a s e d in t h e Supercomputing 98 confe r -ence in a spec ia l s es s ion ca l l ed Netamorphosis T h e N e t a m o r p h o s i s d e m o n -s t r a t i o n s c o n s i s t e d o f 1 7 s i g n if i c an t N G I a p p l i c a t i o n s , r a n g i n g o v e r v is u a l iz a -t i o n , s c e n e a n a l y s i s, s i m u l a t i o n , m a n u f a c t u r i n g , r e m o t e o p e r a t i o n , e t c . F o re x a m p l e , a d e m o n s t r a t i o n e n t i t le d R e a l - T i m e F u n c t i o n a l M R I : W a t c h i n gt h e B r a i n i n A c t i o n s h o w e d h o w o n e c o u l d r e m o t e l y v ie w b r a i n a c t i v i t yw h i le a p a t ie n t w a s p e rf o r m i n g c o g n i t i v e o r se n s o r y - m o t o r t a s k s . T h e s y s t e mc o u l d p r o c e s s f u n c t i o n a l M R I d a t a i n r e a l -t im e , t h o u g h t h e d a t a a c q u i si ti o n ,m a i n c o m p u t a t i o n s , a n d v i s u a l i z a t i o n a l l t o o k p l a c e a t d i f f e r e n t s i t e s c o n -n e c t e d b y a d v a n c e d n e tw o r k s. A n o t h e r d e m o n s t r a t io n e n t i tl e d D i s t r ib u t e dI m a g e S p r e a d s h e e t : E a r t h D a t a f r o m S a t e ll i te t o D e s k t o p s h o w e d h o w s ci -e n t i s t s c o u l d a n a l y z e , p r o c e s s , a n d v i s u a l iz e m a s s i v e a m o u n t s o f g e o l o g ic ,a t m o s p h e r i c , o r o c e a n o g r a p h i c d a t a t r a n s m i t t e d t o t h e i r w o r k s t a t i o n s fr o mE a r t h O b s e r v i n g S y s t e m s a t e l li te s .

5 . 4 D i g i t a l L i b r a r ie s I n i t i a t i v e D L I )T h e o r i g in a l D L I , n o w r e f e r r e d t o a s D L I P h a s e 1 , s t a r t e d a s a j o i n t v e n t u r eo f N S F , D A R P A , a n d N A S A . N o w t h e i n i ti a t iv e i s i n P h a s e 2 , a n d i n c lu d e sa s s p o n s o r s t h o s e a g e n c i e s a s w e ll a s t h e N a t i o n a l L i b r a r y o f M e d i c i n e , t h eL i b r a r y o f C o n g r e ss , a n d t h e N a t i o n a l E n d o w m e n t f o r t h e H u m a n i t i e s .

T h e i n i t i a t i v e s e e k s t o a d v a n c e t h e t e c h n o l o g i e s n e e d e d t o o f f e r i n f o r -m a t i o n e s s e n t i a l l y a b o u t a n y t h i n g , t o a n y o n e , l o c a t e d a n y w h e r e a r o u n d t h en a t i o n a n d t h e w o r l d . A d i g i t a l l i b r a r y i s i n t e n d e d t o b e a v e r y l a r g e - s c a l es t o r e h o u s e o f k n o w l e d g e in m u l t i m e d i a f o r m t h a t is a c c e s si b le o v e r t h e n e t .T h e c o n s t r u c t i o n a n d o p e r a t i o n o f d i g i t a l l i b r a r ie s r e q u i r e s d e v e l o p i n g t e c h -n o l o g ie s f o r a c q u i r i n g i n f o r m a t i o n , o r g a n i z i n g t h i s i n f o r m a t i o n i n d i s t r i b u t e dm u l t i m e d i a k n o w l e d g e b a s e s , e x t r a c t i n g i n f o r m a t i o n b a s e d o n r e q u e s t e d c r i -t e r i a , a n d d e l i v e r i n g i t i n t h e f o r m a p p r o p r i a t e f o r t h e u s e r . T h u s , t h e D L Ip r o m o t e s r e s e a r c h o n i n f o r m a t i o n c o l l e c t i o n , a n a l y s i s , a r c h i v i n g , s e a r c h , f i l -t e r i n g , r e t r i e v a l , s e m a n t i c c o n v e r s i o n , a n d c o m m u n i c a t i o n .

T h e P h a s e 1 is s u p p o r t i n g 6 la r g e c o n s o r t i a c o n s i st in g o f a c a d e m i c a n d in -d u s t r i a l p a r t n e r s . T h e i r m a i n p r o j e c t t h e m e s a n d t h e i r l e a d i n s t i t u t i o n s a r e:g e o g r a p h i c i n f o r m a t i o n s y s t e m s , m a p s a n d p i c t u r e s , c o n t e n t - b a s e r e t r i e v a l( U n i v e r s i t y o f C a l i f o r n i a - S a n t a B a r b a r a ) ; i n t e ll i g e n t i n t e r n e t s e a r c h , s e m a n -t i c r e t ri eva l , s c ien t if i c jou rna l pu b l i sh in g a l t e rn a t iv es (U n ive r s i ty o f I ll ino i s );m e d i a i n t e g r a ti o n a n d a c c es s, n e w m o d e l s o f d o c u m e n t s , n a t u r a l l a n g u a g ep r o c e s s i n g ( U n i v e r s i t y o f C a l i f o r n i a - B e r k e l e y ) ; d i g i t a l v i d e o l ib r a r ie s , s p e e c h ,i m a g e a n d n a t u r a l l a n g u a g e t e c h n o l o g y in t e g r a t i o n ( C a r n e g i e M e l l o n U n i v e r -s i t y ); in t e l li g e n t a g e n t a r c h i t e c t u r e , r e s o u r c e f e d e r a t i o n , A I s e rv i c e m a r k e te c o n o m i e s , e d u c a t i o n a l i m p a c t ( U n i v e r s i t y o f M i c h i g a n ); u n i f o r m a c c e s s, d i s-


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14t r i b u t e d o b j e c t a r c h i te c t u r e s, i n t er f a c e f o r d i s t r i b u t e d i n f o r m a t i o n r e t ri e v a l( S t a n f o r d U n i v e r s i t y ) .T h e P h a s e 1 o f t h e i n i t ia t iv e w a s m a i n l y c o n c e r n e d w i t h l e a r n in g , p r o -t o t y p i n g , a n d e x p e r i m e n t i n g i n t h e s m a l l. T h e P h a s e 2 e x p e c t s t o p u t t h i se x p e r i en c e i n to a c t u a l l y b u i l d in g l a r ge r , o p e r a t i o n a l , a n d u s a b l e s y s t e m s a n dt e s t b e d s . T h e r e i s e m p h a s i s o n l a r g e r c o n t e n t s a n d c o l l e c t i o n s , i n t e r o p e r a b i l -i t y a n d t e c h n o l o g y in t e g ra t io n , a n d e x p a n s i o n o f d o m a i n s a n d u s e r c o m m u -n i t i e s f o r d i g i t a l l i b r a r i e s . T h e s u p p o r t e d a c t i v i t i e s a r e e x p e c t e d t o r a n g et h r o u g h t h e f u ll s p e c t r u m o f f u n d a m e n t a l r e s e a rc h , c o n t e n t a n d c o l l ec t io n sd e v e l o p m e n t , d o m a i n a p p l i c a t i o n s , t e s t b e d s , o p e r a t i o n a l e n v i r o n m e n t s , a n da p p l i c a ti o n s f o r d e v e l o p in g e d u c a t io n a l r e s o u r c es a n d p r e s e r v i n g t h e n a t i o n a lc u l t u r a l h e r i t a g e .5 .5 K n o w l e d g e a n d D i s t r i b u t e d I n t e l li g e n c e K D I )K D I i s a n e w i n i t i a t i v e t h a t N S F e s t a b l i s h e d i n 1 9 9 8 . T h e H P C C r e s e a r c hh a s tr a d i ti o n a l ly b e e n c o n c e n t ra t e d i n t h e N S F ' s C o m p u t e r a n d I n f o r m a t i o nS c ie n c e a n d E n g i n e e r in g d i r e c t o ra t e . T h e K D I i n i t i a ti v e s t e m s f r o m t h e r e-a l iz a t io n t h a t t h e a d v a n c e s i n c o m p u t i n g , c o m m u n i c a t i o n s , a n d i n f o r m a t i o nt e c h n o l o g i e s p r o v i d e u n p r e c e d e n t e d p o s s i b i l i t i e s f o r a c c e l e r a t i n g p r o g r e s s i na ll s p h e r e s o f h u m a n t h o u g h t a n d a c t i o n . K D I s t r e ss e s k n o w l e d g e a s o p p o s e dt o i n f o r m a t i o n , b u t r e a li z e s, o f c o u r s e , t h a t i n t e ll i g e n t g a t h e r i n g o f i n f o r m a -t i o n i s a p r e r e q u i s i t e t o c r e a t i n g k n o w l e d g e . T h u s , a g o a l o f K D I i s t o i m p r o v et h e h u m a n a b i l i t y t o d i s c o v e r , c o l l e c t , r e p r e s e n t , s t o r e , a p p l y , a n d t r a n s m i ti n fo r m a t i o n . T h i s is t o l e ad t o i m p r o v e m e n t s i n t h e w a y s to c r e a t e k n o w l e d g ea n d i n t h e a c t u a l a c q u i s i t io n o f n e w k n o w l e d g e . T h e K D I r e s e a r c h i s c l a ss i fi e di n t o t h r e e c o m p o n e n t s :

1 . K n o w l e d g e N e t w o r k i n g ( K N )2 . L e a r n i n g a n d I n t e l l i g e n t S y s t e m s ( L I S )3 . N e w C o m p u t a t i o n a l C h a l le n g e s ( N C C )

T h e K N c o m p o n e n t a i m s a t b u i l d i n g a n o p e n a n d c o n t e x t - r i c h e n v i r o n m e n tf o r o n l i n e i n t e r a c t i o n s a m o n g i n d i v i d u a l s a s w e ll a s g r o u p s . F o r s u c h a ne n v i r o n m e n t t o a r i s e , a d v a n c e s h a v e t o b e m a d e i n t h e t e c h n i q u e s f o r c o l -l e c t in g a n d o r g a n i z i n g i n f o r m a t i o n a n d d i s c o v e r i n g k n o w l e d g e f r o m i t . T h eK N - e n a b l e d v a s t s c a le o f i n f o rm a t i o n a c q u i s i ti o n a n d t h e p o w e r t o u n c o v e rk n o w l e d g e b u r i e d i n c o l l e c t e d d a t a h a s g r a v e i m p l i c a t i o n s f o r p r i v a c y a n do t h e r h u m a n i n t e r e s t m a t t e r s . H e n c e , K N i s a l s o c o n c e r n e d w i t h r e s e a r c h o ns o c ia l , s o c i e t a l , e t h i c al , a n d o t h e r a s p e c t s o f n e t w o r k e d i n f o r m a t i o n .T h e f o cu s o f t h e L IS c o m p o n e n t o f K D I i s t o b e t t e r u n d e r s t a n d t h e p r o c e s so f l e a r n in g i ts e lf , a s i t o c c u r s in h u m a n s , a n i m a l s , a n d a r t if i c ia l s y s t e m s . T h i su n d e r s t a n d i n g i s t o b e u s e d f o r i m p r o v i n g o u r o w n l e a r n i n g s k i ll s, d e v e l o p i n gb e t t e r t e a c h i n g m e t h o d s , a n d c r e a t i n g i n t e l l i g e n t a r t i f a c t s .

T h e N C C c o m p o n e n t is i n t h e s p ir i t o f N S F s C h a l l e n g e s p r o g r a m s , s u cha s G r a n d C h a l l e n g es , N a t i o n a l C h a l l e n g e s , a n d M u l t i d i s c i p l i n a r y C h a l l e n g e s .


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5

In [1], these programs were described, and their impact and some of theiraccomplishments were stated. The NCC component continues to seek solu-tions of very complex scientific and engineering problems, ones that are com-putationally expensive, data intensive, and require multidisciplinary teamapproaches. The Challenges research and the advance in high-performancecomputing and communications system have a mutually benefiting push-pullrelationship; the former stress tests the latte r, and the latt er helps the formergrow in scale and scope. NCC research aims to improve our ability to modeland simulate complex systems such as the oceans or the brain. In adopt-ing the Challenges research, the KDI initiative sees it as another knowledgecreation activity.

In 1998, NSF made 40 awards for KDI research for a to tal funding of$51.5M. The awards span a broad range of topics, vast scopes of research,and investigators representing diverse disciplines and institutions. The 1999KDI competition is in process.

6 HPC C E va l u a t i onGeneral directions as well as clear objectives were defined for the HPCC pro-gram from the very beginning. Thus, some evaluation is built into the pro-gram. Some objectives naturally lead to quantifiable measures of progress,such as computation speeds in teraflops, communication bandwidth in giga-bits, network extent in number of connected nodes, etc. On the other hand,there are qualitative aspects of progress, such as scientific breakthroughs,innovative industrial practices, societal penetration of knowledge and tech-nology, quali ty of work force trained, etc.

The evaluation of the STC and SC programs has already been mentioned.Other parts of the NSF HPCC program have also produced impressive results.For the effectiveness of the HPCC program as whole, a number of evaluationstudies have been done. The Branscomb Report [19], is devoted to studyingthe means for making the program more productive. A thorough assessmentof the effectiveness of the program is undertaken in the Brooks-SutherlandRepor t [20]. The purpose of a more recent recent study [21] is to suggest themost important future HPCC applications, specially the ones with highestnational, societal, and economic impact.

There is consensus that the HPCC program has been successful on mostfronts. Not only the year by year milestones for quantifiable progress havebeen met, but the activities undertaken by the program have led to severalsignificant, unantic ipated beneficial developments. The launch of new impor-tant HPCC-inspired initiatives witnesses the programs strong momentum.But as the next section shows, there is a perception that the HPCC programis underfunded and the progress resulting from it is going to decelerate unlessnewer and larger investments are added to it.


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67 P r e s id e n t s I n f o r m a t i o n T e c h n o l o g y A d v i s o r yC o m m i t t e e P I T A C )PITAC was established in February 1997 to provide advice to the Adminis-tration on all areas of computing, communications, and information technol-ogy. This committee at present consists of 26 research leaders representingacademia and the industry. It issued an interim report in August 1998 anda final one in February 1999 [22], after a series of meetings and broad con-sultations with the research community. This report examines the impact ofR&D in Information Technology (IT) on US business and science, and makesa number of recommendations for further work.

The PITAC report observes that the past IT R&D through HPCC andother programs is a significant factor in the nations world leadership positionin science, industry, business, and the general well-being of the citizenry. ITadvances are responsible for a third of the US economic growth since 1992,and have created millions of high-paying new jobs. The computational ap-proach to science in conjunction with the HPCC algorithms, software, andinfrastructure have helped the US scientists make new discoveries. The com-petitiveness of US economy is owed much to the efficiencies resulting from ITin engineering design, manufacturing, business, and commerce.

If IT is the engine that is driving the economy, then obviously it needs tobe kept running by further investment. The PITAC report argues that theIT industry is spending the bulk of its own resources, financial and human,on near-term development of new products for an exploding market. The ITindustry can contribute only a small fraction of the long-term R&D invest-ment needed. Moreover, the industry does not see any immediate benefits ofthe scientific and social components of IT, and therefore has no interest inpursuing them. After estimating the total US R&D expenditure on IT, andthe Federal and industrial shares of it, the PITAC conclusion is tha t the Fed-eral support of the Information Technology (IT) R&D is grossly inadequate.Moreover, it is focused too much on near-term and applied research.

PITAC has recommended increments of about 1.3 billion per year forthe next 5 years. PITAC has also identified the following four high priorityareas as main targets of increased investment.S o f t w a r e : Software production methodologies have to be dramatically

improved, by fundamental research, to deliver robust, usable, manageable,cost-effective software.Scalable I n f o r m a t i o n I n f r a s t r u c t u r e : With the ever increasing size,complexity, and sheer use of networks, research is needed on how to build

networks tha t can be easily extended yet remain reliable, secure, and easy touse

High-End Computing: Scientific research and engineering design arebecoming more and more computational. The increasing complexity of prob-lems demand ever faster computing and communications. Thus, sustained


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8

Computation and Gigabit Local Area Networks, Lect. Notes in Control andInformation Sci. # 226, Springer-Verlag Berlin, 1997.2. A National Computing Initiative: The Agenda for Leadership, Society for In-dustrial and Applied Mathematics, Philadelphia, PA, 1987.3. Toward a National Research Network, National Academy Press, Washington,D.C., 1988.4. Supercomputers: Directions in Technology and Applications, National AcademyPress, Washington, D.C., 1989.5. Keeping the U.S. Computer Industry Competitive: Defining the Agenda, Na-tional Academy Press, Washington, D.C., 1990.6. Grand Challenges: High Performance Computing and Communications ( FY1992 Blue Book ), Federal Coordinating Council for Science, Engineering, andTechnology, c/o National Science Foundation, Washington, D.C., 1991.7. Grand Challenges 1993: High Performance Computing and Communications( FY 1993 Blue Book ), Federal Coordinating Council for Science, Engineering,and Technology, c/o National Science Foundation, Washington, D.C., 1992.8. High Performance Computing and Communications: Toward a National Infor-mation Infrastructure ( FY 1994 Blue Book ), Office of Science and TechnologyPolicy, Washington, D.C., 1993.9. High Performance Computing and Communications: Technology for a NationalInformation Infrastructure ( FY 1995 Blue Book ), National Science and Tech-nology Council, Washington, D.C., 1994.

10. High Performance Computing and Communications: Foundation for America'sInformation Future ( FY 1996 Blue Book ), National Science and TechnologyCouncil, Washington, D.C., 1995.11. High Performance Computing and Communications: Advancing the Frontiersof Information Technology( FY 1997 Blue Book ), National Science and Tech-nology Council, Washington, D.C., 1996.12. Technologies for the 21st Century ( FY 1998 Blue Book ), National Scienceand Technology Council, Washington, D.C., 1997.13. Networked Computing for the 21st Century ( FY 1999 Blue Book ), NationalScience and Technology Council, Arlington, VA, 1998.14. National Science Foundation's Science and Technology Centers: Building an In-terdisciplinary Research Program,National Academy of Public Administration,Washington, D.C., 1995.15. An Assessment of the National Science Foundation's Science and TechnologyCenters Program, National Research Council, National Academy Press, Wash-ington, D.C., 1996.16. Report of the Task Force on the Future of the NSF Supercomputing Centers( Hayes report ), Pub. NSF 96-46, National Science Foundation, Arlington,VA.17. The Unpredictable Certainty: Information Infrastructure through 2000,Na-

tional Research Council, National Academy Press, Washington, D.C., 1996.18. More Than Screen Deep: Toward Every-Citizen Interfaces to the Nation's In-formation Infrastructure ( Biermann Report ), National Research Council, Na-tional Academy Press, Washington, D.C., 1997.19. From Desktop to Teraflop: Exploiting the U.S. Lead in High Performance Com-puting ( Branscomb Report ), Pub. NSB 93-205, National Science Foundation,Washington, D.C., August 1993.


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23

a i r n e s s a n d s e c u r i t y D e n i a l - o f - s e rv i c e c o n d i t i o n s m a y a r i s e i f f lo w s c a n r e -s e r v e d i s p r o p o r t i o n a l a m o u n t s o f r e s o u r c e s o r i f f lo w s c a n e x c e e d t h e i r r e se r -v a t i o n s. W e p r e s e n t l y c o n s i d e r fa i rn e s s i n a c c e p t i n g r e s e r v a t i o n s a l o c a l p o l ic yi s su e ( m u c h l ik e b i ll i n g ) w h i c h m a y b e a d d r e s s e d a t a f u t u r e t i m e .

S o u r c e s v i o l a t i n g t h e a g r e e d u p o n r e s e r v a t i o n s a r e a r e a l t h r e a t a n d n e e dt o b e p o l i c e d . A s c a la b l e p o l i c in g m e c h a n i s m t o a l l o w r o u t e r s t o i d e n t i f yn o n - c o n f o r m a n t f lo w s b a s e d o n c e r t a i n h e u r i s t i c s is t h e s u b j e c t o f o n g o i n g r e -s e ar ch . S u c h a m e c h a n i s m c a n b e c o m b i n e d w i th m o r e t r a d i t i o n a l a p p r o a c h e s ,e .g . p o l i c i n g o f i n d i v i d u a l f lo w s a t l o c a t i o n s w h e r e s c a l a b i l i t y is le s s i m p o r -t a n t , e . g . a t n e t w o r k e d g e s .

T h e r e s t o f t h i s p a p e r is o r g a n i z e d a s fo ll ow s . S e c ti o n 2 p r o v i d e s a m o r ed e t a i l e d p r o t o c o l o v e r v ie w . S e c t i o n 3 d e s c r ib e s a s i m p l e a l g o r i t h m f o r t h ei m p l e m e n t a t i o n o f t h e t ra f fi c e s t i m a t o r . F i n a ll y , p r o t o c o l o p e r a t i o n is il lu s-t r a t e d w i t h s o m e s i m u l a t i o n re s u l t s in s e c ti o n 4 a n d t h e p a p e r c o n c l u d e s w i t hs e c t i o n 5 .

2 A r c h i t e c t u r e o v e r v i e wT h e p r o p o s e d a r c h i t e c t u r e u s es t w o p r o t o c o l s to m a n a g e r e s e r v a t io n s : a re s e r-v a t i o n p r o t o c o l t o es t a b l is h a n d m a i n t a i n t h e m , a n d a f e e d b a c k p r o t o c o l t oi n f o r m t h e s e n d e r a b o u t t h e r e s e r v a t i o n s ta t u s .

Sender Data reservations Receiver

Router

F i g . 1 . O v e r v ie w o f t h e c o m p o n e n t s i n S R P .

F i g u r e 1 i l lu s t r a t es t h e o p e r a t i o n o f t h e t w o p r o t o c o l s :9 D a t a p a c k e t s w i t h r e s e r v a t io n i n f o r m a t i o n a r e s e n t fr o m t h e s e n d e r t o t h e

r e c e iv e r . T h e r e s e r v a t i o n i n f o r m a t i o n c o n s i s ts i n a p a c k e t t y p e w h i ch c a nt a k e t h r e e v a lu e s, o n e o f t h e m b e i n g o r d i n a r y b e s t - e f f o r t ( s e c ti o n 2 .2 ). I ti s p r o c e s s e d b y r o u t e r s , a n d m a y b e m o d i f i e d b y r o u t e r s . R o u t e r s m a ya l s o d i s c a r d p a c k e t s ( s e c t i o n 2 . 1 ) .9 T h e r e c e i v e r s e n d s f e e d b a c k i n f o r m a t i o n b a c k t o t h e s e n d e r . R o u t e r s o n l yf o r w a r d t h i s i n f o r m a t i o n ; t h e y d o n ' t n e e d t o p r o c e s s i t ( s e c t i o n 2 . 3 ) .R o u t e r s m o n i t o r t h e r e s e r v e d tr a ff ic w h i c h is e ff e c ti v e ly p r e s e n t a n d a d j u s t

t h e i r g l o b a l s t a t e i n f o r m a t i o n a c c o r d i n g l y . S e c t i o n s 2 . 1 t o 2 . 3 i l l u s t r a t e t h er e s e r v a t i o n a n d f e e d b a c k p r o t o c o l .


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242 1 R e s e r v a t i o n p r o t o c o lThe reservation protocol is used in the direction from the sender to the re-ceiver. It is implemented by the sender, the receiver, and the routers betweenthem. As mentioned earlier, the reservation information is a packet typewhich may take three values:R e q u e s t This packet is part of a flow which is trying to gain reserved status.

Routers may accept, degrade or reject such packets. Wh en tou ters acceptsome request packets, then they commit to accept in the future a flow ofreserved packets at the same rate. The exact definition of the rate is partof the estimator module.

R e s e r v e d This label identifies packets which are inside the source's profileand are allowed to make use of the reservation previously established byrequest packets. Given a correct estimation, routers should never discardreserved packets because of resource shortage.B e s t e f f o r t No reservation is attempted by this packet.Packet types are initially assigned by the sender, as shown in figure 2.

A traffic source (i.e. the application) specifies for each packet if that packetneeds a reservation. If no reservation is necessary, the packet is simply sent asbest-effort. If a reservation is needed, the p rotoco l entity checks if an alreadyestablished reservation at the source covers the current packet. If so, thepacket is sent as reserved otherwise an additional reservation is requested bysending the packet as request.

Application

N e e d sre se rv a t ion

D o e s n t n e e dre se rv a t ion

Protocol stackYesI e o r v n l

~ establish ed? ~ _R e q u e s tNoBe s t e f f o r t

Fig. 2. Initial packet type assignment by sender.

Each router performs two processing steps (see also figure 3). First, foreach request and reserved packet the estimator updates its current estimate ofthe resources used by the aggregate flows and decides whether to accept thepacket (packet admission control). Then, packets are processed by variousschedulers and queue managers inside the router.

9 When a reserved packet is received, the est imator updates the resource es-timation. Th e packet is automatically forwarded unchanged to the sched-


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25u l e r w h e r e it w i ll h a v e p r i o r i t y o v e r b e s t - e f f o r t t r a f fi c a n d n o r m a l l y i s n o td i s c a r d e d .9 W h e n a request p a c k e t is r e ce i v e d , t h e n t h e e s t i m a t o r c h e c k s w h e t h e ra c c e p t i n g t h e p a c k e t w ill n o t e x c e e d t h e a v a i la b l e r e s o u r c e s. I f t h e p a c k e tc a n b e a c c e p t e d , i t s request l a b e l is n o t m o d i f i e d . I f t h e p a c k e t c a n n o t b ea c c e p t e d , t h e n i t i s d e g r a d e d t o b e s t - e f f o r t9 I f a s c h e d u l e r o r q u e u e m a n a g e r c a n n o t a c c e p t a r e s e r v e d o r r e q u e s tp a c k e t , t h e n t h e p a c k e t i s e i t h e r d i s c a r d e d o r d o w n g r a d e d t o best-effort.

Reserved

Request

Be st effort

S R P e s t im a t o r P a c k e t s c h e d u l e r

Update the ] / Can the packet ];stimatedb a n d w i d t h J Reserved ~ | be schedule in the / Yes ~ Reservedt ~ reserve d service 1__... .. .1~.Request~ Yes llequeS [ class ? Jls an update o f th e l /estimated bandwidth Noaccepmble N o ~ e S t e f f o r t _ _ [ C a n t h e p a c k e t l Y e s

be schedule in the ~ Be st effortbest effort class ?

N ~ D i sc a rd

F ig . 3 . P a c ke t p r oc e s s ing by r ou te r s .

N o t e t h a t t h e r e s e rv a t io n p ro t o c o l m a y " t u n n e l " t h r o u g h r o u t e r s t h a td o n ' t i m p l e m e n t r e s e rv a t io n s . T h i s a l lo w s t h e u s e o f u n m o d i f i e d e q u i p m e n ti n p a r t s o f t h e n e t w o r k w h i c h a r e d i m e n s i o n e d s u c h t h a t c o n g e s t i o n is n o t ap r o b l e m .2 2 P a c k e t t y p e e n c o d i n gR F C 2 4 7 4 [9] d e fi n es t h e u s e o f a n o c t e t i n t h e I P v 4 a n d I P v 6 h e a d e r f o rD i f f e r e n t i a te d S e rv i ce s (D S ) . T h i s f ie ld c o n t a i n s t h e D S C o d e P o i n t ( D S C P ) ,w h i c h d e t e r m i n e s h o w t h e r e s p e c t i v e p a c k e t is t o b e t r e a t e d b y r o u t e r s ( P e r -H o p B e h a v i o u r , P H B ) . R o u t e r s a r e al lo w e d t o c h a n g e t h e c o n t e n t o f a p a c k e t ' sD S f i e l d ( e . g . t o s e l e c t a d i f f e r e n t P H B ) .

A s i l lu s t r a t e d i n fi g u re 4 , S R P p a c k e t t y p e s c a n b e e x p r e s s e d b y i n t r o d u c -i n g t w o n e w P H B s ( fo r request a n d f o r reserved , a n d b y u s i n g t h e p r e - d e f i n e dD S C P v a l u e 0 f o r b e s t - e f f o r t . D S C P v a l u e s f o r request a n d reserved c a n b ea l l o c a t e d l o c a l l y i n e a c h D S d o m a i n .2 3 F e e d b a c k p r o t o c o lT h e f e e d b a c k p r o t o c o l is u s e d t o c o n v e y i n f o r m a t i o n o n t h e s u c c es s o f r e s e r-v a t i o n s a n d o n t h e n e t w o r k s t a t u s f r o m t h e r e c e i v e r t o t h e s e n d e r . U n l i k e t h e


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6

PHB DSCPDdault = 0oooooSRP I~lquesl I" .. .. ..SRP Rm med = y,Jx'J3tY

9 7~s

IPv4 header 'Vet I HL i TO6 '* Total lengthFragment ID Rg I Frag.offset

I Protocol ChecksumSourceaddress

Destination addressOfXions, data ... i

Fig . 4. Packet ty pe encoding using Different iated Services (IPv4 exam ple).

r e s e rv a t i o n p ro t o c o l , th e f e e d b a c k p ro t o c o l d o es n o t n e e d t o b e i n t e rp r e t e d b yro u t e r s , b e c a u s e t h e y c a n d e t e rm i n e t h e r e s e rv a t i o n s t a t u s f ro m t h e s e n d e r scho ice o f packe t t ypes .

F e e d b a c k i n fo rma t i o n i s c o l l e c t e d b y t h e r e c e i v e r a n d i t i s p e r i o d i c a l l ys e n t t o t h e s e n d e r. T h e f e e d b a c k c o n s is t s o f t h e n u m b e r o f b y t e s i n requesta n d reserve p a c k e t s t h a t h a v e r e a c h e d t h e r e c e i v e r , a n d t h e l o c a l t i me a tthe rece ive r a t wh ich the feedback message was gene ra t ed .

R e c e i v er s c ol le c t f e e d b a c k i n fo rm a t i o n i n d e p e n d e n t l y fo r e a c h s e n d e r a n ds e n d e r s ma i n t a i n t h e r e s e rv a t i o n s t a t e i n d e p e n d e n t l y fo r e a c h r e c e i v e r . N o t et h a t , i f mo r e t h a n o n e f lo w t o t h e s a me d e s t i n a t i o n e x is t s , a t t r i b u t i o n o freservat ions i s a loca l decis ion a t the source .

1 0 i 1 1 2 1 3 1 4 1 5 ( = 1 7V~ I Re tervedtO t

.Reaor,,~d Num REQ (tO)Re Berved Num REQ (t)P,e~lt V~ Num RSV (tO)P, ~t ve d Num RSV (t)

Fig. 5. Feedback message format .

F i g u re 5 il l u s tr a t e s t h e c o n t e n t o f a f e e d b a c k me s sa g e : t h e t i me w h e n t h eme s s a g e w as g e n e ra t e d ( t ), a n d t h e n u mb e r o f b y t e s i n request a n d reservep a c k e t s r e c e i ve d a t t h e d e s t i n a t i o n (R E Q a n d R S V ) . A l l c o u n t e r s w r a p b a c kto ze ro when they ove r f low.

In o rd e r t o i mp ro v e t o l e r a n c e t o p a c k e t l o s s , a l s o t h e i n fo rma t i o n s e n tin the p rev ious feedback message (a t t ime tO) is rep ea te d . Po r t ion s o f t hemessage a re re se rved to a l low fo r fu tu re ex tens ions .


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72 4 S h a p i n g a t t h e s e n d e rT h e s e n d e r d e c i d e s w h e t h e r p a c k e t s a r e s e n t a s reserved or request b a s e do n i ts o w n e s t i ma t e o f t h e r e s e rv a t i o n i t h a s r e q u e s t e d a n d o n t h e l ev e l o fr e s e rv a t i o n a l o n g t h e p a t h t h a t h a s b e e n c o n f i rme d v i a t h e f e e d b a c k p ro t o c o l .A s o u rc e a l w ay s u s es t h e mi n i m u m o f t h e s e t w o p a r a m e t e r s t o d e t e rm i n e t h ea p p r o p r i a t e o u t p u t t r af f ic p rof il e.

F u r t h e rmo re , t h e s e n d e r n e e d s t o f i l t e r o u t s ma l l d i f f e r e n c e s b e t w e e nt h e a c t u a l r e s e rv a t i o n a n d t h e f e e d b a c k i n o rd e r t o a v o i d r e s e rv a t i o n s f ro mdr i f t i ng , and i t mus t a l so ensu re tha t request p a c k e t s d o n o t i n t e r f e r e w i t hconges t ion -con t ro l l ed t ra f fi c e .g . T C P ) in an un fa i r way [10].2 5 E x a m p l eF i g u re 6 p ro v i d e s t h e o v e ra l l p i c t u r e o f t h e r e s e rv a t i o n a n d f e e d b a c k p ro t o -c ol s f o r t w o e n d - s y s t e ms c o n n e c t e d t h ro u g h ro u t e r s R 1 a n d R 2 . T h e i n i ti a lre source acqu i s i t i on phase i s fo l lowed by the g ene ra t ion o f requ es t pack e t s a f -t e r t h e f i r s t f e e d b a c k me s s a g e a r r i v e s . D o t t e d a r ro w s c o r r e s p o n d t o d e g ra d e drequest p a c k e ts , w h ic h p a s se d t h e a d mi s s i o n c o n t ro l t e s t a t r o u t e r R 1 b u tc o u l d n o t b e a c c e p t e d a t r o u t e r R b e c a u s e o f r e s o u rc e s h o r t a g e . D e g ra d a -t ion o f requests is t a k e n i n t o a c c o u n t b y t h e f e e d b a c k p ro t o c o l . A f t e r r e c e i v i n gt h e f e e d b a c k i n fo rm a t i o n t h e s o u rc e s e n d s reserved p a c k e t s a t a n a p p r o p r i a t era t e , wh ich i s sma l l e r t han the one a t wh ich request p a c k e t s w e re g e n e ra t e d .

R E Q U E S Tdata packet se.g. at 2Mbps)

FeedbacktrafSpec= 1M bpsR E S E R V E Ddata packet s

R E Q U E S T packe t - - - z~ - R E S E R V E D packe t.......~ D eg r aded R E Q U E S T packe t

F eedback packe t B E S T - E F F O R T )

Fig. 6. Reservat ion and feedback protocol diagram.

2 6 M u l t i c a s tIn o rd e r t o s u p p o r t mu l t i c a s t t r af f ic , w e h a v e p ro p o s e d a d e s ig n t h a t s l ig h t l ye x t e n d s t h e r e s e rv a t i o n me c h a n i s m d e s c r i b e d i n t h i s s e c t i o n s . R e f i n e me n t o f


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29a n i n c r e as e d n u m b e r o f r e q u es ts . T h e s e n d e r m u s t n o t i n t e r p r e t t h o s e r e -q u e s t s a s a d ir e c t i n c r e a s e o f t h e r e s e r v a t i o n . I n s t e a d , t h e s e n d e r e s t i m a t o rm u s t c o r r ec t t h e f e e d b a c k i n f o r m a t i o n a c c o rd i n g ly , w h i c h i s a c h i e v e d t h r o u g ht h e c o m p u t a t i o n o f t h e m i n i m u m o f t h e f e ed b a c k a n d o f t h e r e s o u r ce a m o u n tr e q u e s t e d b y t h e s o u r c e .

O u r a r c h i t e c t u r e is i n d e p e n d e n t o f t h e s p e c if ic a l g o r i t h m u s e d t o i m p l e -m e n t t h e e s t i m a t o r . S e c t io n s 3 .1 a n d 3 .2 d e s c r i b e tw o d i f f er e n t s o l u ti o n s . T h ed e f in i t i o n a n d e v a l u a t i o n o f a l g o r i t h m s f o r r e s e r v a t i o n c a l c u l a t i o n i n h o s t s a n dr o u t e r s i s s ti ll o n g o i n g w o r k . A d e t a i l e d a n a l y s i s o f t h e e s t i m a t i o n a l g o r i t h m sa n d a d d i t i o n a l i m p r o v e m e n t s c a n b e f o u n d i n [12].

3 1 B a s ic e s t i m a t i o n a l g o r i t h mT h e b a s i c a l g o r i t h m w e p r e s e n t h e r e is s u i t a b l e f o r s o u r c e s a n d d e s t i n a t i o n s ,a n d c o u ld b e u s ed a s a r o u g h e s t i m a t o r b y r o u t e r s . T h i s e s t i m a t o r c o u n t st h e n u m b e r o f r e q u e s t s i t r e c ei v e s ( a n d a c c e p t s ) d u r i n g a c e r t a i n o b s e r v a t i o ni n t e r v a l a n d u s e s t h i s as a n e s t i m a t e f o r t h e b a n d w i d t h t h a t w i ll b e u s e d i nf u t u r e i n t e rv a l s o f t h e s a m e d u r a t i o n .

I n a d d i t i o n t o r e q u e s t s f o r n e w r e s e r v a t io n s , t h e u s e o f e x i s t i n g r e s e r v a -t io n s n e e d s t o b e m e a s u r e d t o o . T h i s w a y , r e s e r v a t i o n s o f s o u r c e s t h a t s t o ps e n d in g o r t h a t d e c r ea s e t h e i r s en d i n g r a t e c a n a u t o m a t i c a l l y b e r e m o v e d .F o r th i s p u r p o s e t h e u s e o f r e s e r v a ti o n s c a n b e s i m p l y m e a s u r e d b y c o u n t i n gt h e n u m b e r o f re se rv e d p a c k e t s t h a t a r e r e c e i v e d i n a c e r t a i n i n t e r v a l .

T o c o m p e n s a t e f o r d e v i a t i o n s c a u s e d b y d e la y v a r i a ti o n s , s p u r i o u s p a c k e tl o ss (e .g . i n a b e s t - e f f o r t p a r t o f t h e n e t w o r k ) , e tc . , r e s e r v a t i o n s c a n b e h e l df or m o r e t h a n o n e o b s e r v a t i o n in t er v a l. T h i s c a n b e a c c o m p l i s h e d b y r e m e m -b e r i n g t h e o b s e r v e d t ra f fi c o v e r s e v e r a l i n t e rv a l s a n d u s i n g t h e m a x i m u m o ft h e s e v a l u e s ( s t e p 3 o f t h e f o l lo w i n g a l g o r i t h m ) . G i v e n a h o l d t i m e o f h o b s e r -v a t io n i n te r v al s , t h e m a x i m u m a m o u n t o f r e s o u rc e s w h ic h c a n b e a l l o c a t e dM a x r e s a n d r e q ( t h e t o t a l n u m b e r o f re se rv e d a n d re que s t by t e s r e c e i v e d i na g i v e n o b s e r v a t i o n i n t e rv a l ) , t h e r e s e r v a t i o n R ( in b y t e s ) is c o m p u t e d b y ar o u t e r a s f o ll o w s. G i v e n a p a c k e t o f n b y t e s :i f p a c k e t _ t y p e = = R E Q )

i f R + r e q + n < M a x ) {a c c e p t ;r e q = r e q + n ; / / s t e p 1

}e l s e d e g r a d e

i f p a c k e t _ t y p e = = R E S)i f r e s + n < R ) {

a c c e p t ;r e s = r e s + n ;

e l s e d e g r a d e

step 2


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3ow h e r e i n i t i a l l y R , r e s r e q = O . A t t h e e n d o f e a c h o b s e r v a t i o n c y c l e th ef o ll o w i ng s te p s a r e c o m p u t e d :

f o r i -- h ; i > I ; i - - ) R E i ] = R [ i - l ] ;R I l l = r e s + r e q ;R = m a x R [ h ] , R [ h - 1 ] , . . . , R [ l ] ) ; / / s t e p 3r e s = r e q = O ;

T h e s a m e a l g o r i th m c a n b e r u n b y t h e d e s t i n a t i o n w i t h t h e o n l y d if fe r en c et h a t n o a d m i s s i o n c h ec k s a r e n e e d e d .

E x a m p l e s o f t h e o p e r a t i o n o f t h e b a s ic a l g o r i t h m a r e s h o w n i n s e c t i o n 4 .1 .T h i s e a s y a l g o r i t h m p r e s e n t s s e v e r al p r o b le m s . F i r s t o f a ll , t h e c h o i c e o f

t h e r i g h t v a l u e o f t h e o b s e r v a t i o n i n t e r v a l is c ri t i c a l a n d d i f fi c u l t. S m a l l v a l u e sm a k e t h e e s t i m a t i o n d e p e n d e n t o n b u r s t s o f r e s e r v e d o r r e q u e s t p a c k e t s a n dc a u s e a n o v e r e s t i m a t i o n o f t h e r e s o u r c e s n e e d e d . O n t h e o t h e r h a n d , l a rg ei n t e r v a l s m a k e t h e e s t i m a t o r r e a c t s l o w l y t o c h a n g e s i n t h e t r a f fi c p r o f il e .T h e n , t h e s t r ic t n e s s o f t ra f fi c a c c e p t a n c e c o n t r o l is f ix e d , w h i le a d a p t i v i t yw o u l d b e h i g h l y d e s i r a b le i n o r d e r t o m a k e t h e a l l o c a t i o n o f n e w r e s o u r c e ss t r i c t e r as t h e a m o u n t o f r e s o u r c e s r e s e r v e d g e t s c lo s e r t o t h e m a x i m u m .T h e s e p r o b l e m s c a n b e s o l v ed b y d e v is i ng a n a d a p t i v e e n h a n c e d a l g o r i t h ml ik e t h e o n e d e s c r i b e d i n t h e f o l lo w i n g s ec t i o n .

3 .2 E n h a n c e d e s t i m a t i o n a l g o r i t h mI n s t e a d o f u s i n g th e s a m e e s t i m a t o r i n e v e r y n e t w o r k c o m p o n e n t , w e c a n e n -h a n c e t h e p r e v i o u s a p p r o a c h s o t h a t s e n d e r s a n d r e c e iv e r s s ti ll r u n t h e s i m p l ea l g o r i t h m d e s c r i b e d a b o v e , w h i le r o u t e r s i m p l e m e n t a n i m p r o v e d e s t i m a t o r .

Frequentlyupdated ~ Inf requen t ly pda ted

Exp. w eighted v erageEstimateb e f~ sm ~ 1 7 6 t Y ~ ~ C o r re c t io n 13 ~ e ~ ~U n c ~ I S e rv ic e? r e }I Effec t ive andwidth I i I V i r tua l ueue I J

t \ ~ vRESERVEDand acceptedR E Q U E S Tpackets

F ig . 8 . S c he m a t i c de s ign o f a n a da p t ive e s t im a to r .

Feedback

W e d e s c r i b e a n e x a m p l e a l g o r i t h m i n d e t a i l in [ 11 ]. It c o n s i s t s o f t h ep r i n c ip a l c o m p o n e n t s i l l u s t ra t e d i n f ig u r e 8: t h e e f f e c ti v e b a n d w i d t h u s e d b yr e s e r v e d a n d a c c e p t e d r e q u e s t p a c k e ts is m e a s u r e d a n d t h e n s m o o t h e d b y c al-c u l a t in g a n e x p o n e n t i a l l y w e i g h t e d a v e r a g e 7 ) . T h i s c a l c u l a t i o n is p e r f o r m e df o r e v e r y s i n g l e p a c k e t .


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31T h e e s t i m a t e 7 is m u l t ip l i e d w i t h a c o r r e c t i o n f a c t o r / 3 i n o r d e r t o c o r r e c t

f o r s y s t e m a t i c e r r o r s i n t h e e s t i m a t i o n . P a c k e t s a r e a d d e d t o a v i r t u a l q u e u ei.e . a c o u n t e r ) , w h i c h is e m p t i e d a t t h e e s t i m a t e d r a t e . I f t h e e s t i m a t e is t o o

h i g h , t h e v i r t u a l q u e u e s h r in k s . I f t h e e s t i m a t e is t o o l ow , th e v i r t u a l q u e u eg r o w s . B a s e d o n t h e s iz e o f t h e v i r t u a l q u e u e , ~ c a n b e a d j u s t e d .

4 S i m u l a t i o nS e c t i o n 4 .1 p r o v i d e s a t h e o r e t i c d e s c r i p t i o n o f t h e b e h a v i o r o f t h e r e s e r v a t i o nm e c h a n i s m i n a v e r y s i m p l e e x a m p l e , w h i le s e ct i o n 4 .2 s h o w s t h e s i m u l a t e db e h a v i o r o f t h e p r o p o s e d a r c h i te c t u r e .

4 1 R e s e r v a t i o n e x a m p l eT h e n e t w o r k w e u s e t o i ll u s t r a t e t h e o p e r a t i o n o f t h e r e s e r v a t i o n m e c h a n i s m ,is s h o w n i n f i g u r e 9 : t h e s e n d e r s e n d s o v e r a d e l a y - l e s s l in k t o t h e r o u t e r , w h i c hp e r f o r m s th e r e s e r v a t i o n a n d f o r w a r d s t h e t r a ff i c o v e r a l in k w i t h a d e l a y o ft w o t i m e u n i t s t o t h e r e ce i v er . T h e r e c e iv e r p e r i o d i c a l l y r e t u r n s f e e d b a c k t ot h e s e n d e r .

T h e s e n d e r a n d t h e r e c ei v er b o t h u s e t h e b a s ic e s t i m a t o r a l g o r i t h m d e -s c r i b e d i n s e c ti o n 3 .1 . T h e r o u t e r m a y - a n d t y p i c a l l y w i ll - u s e a d if f e r e n ta l g o r i t h m e .g . t h e o n e d e s c r i b e d i n s e c t i o n 3. 2 ).

Sender Router Receiver~xND elay=0u ~ ] Delay=2u OLocalestimate nd reservation n feedback

F i g . 9 . E x a m p l e n e t w o r k c o n f ig u r a ti o n .T h e b a n d w i d t h e s t i m a

[G. Cooperman, E. Jessen, G. Michler (Auth.), (BookZa.org)

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