Two-rate three-color marker - Dipartimento di Elettronica ed ...
Two-rate three-color marker - Dipartimento di Elettronica ed ...
Two-rate three-color marker - Dipartimento di Elettronica ed ...
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Course of Multime<strong>di</strong>a Internet (Sub-course”Reti Internet Multime<strong>di</strong>ali”), AA 2010-2011 Prof. Paolo Giacomazzi<br />
Politecnico <strong>di</strong> Milano, <strong>Dipartimento</strong> <strong>di</strong> <strong>Elettronica</strong> e Informazione, Via Ponzio, 34/5, 20133 MILANO, ITALY<br />
Single-<strong>rate</strong> <strong>three</strong>-<strong>color</strong> <strong>marker</strong> (srTCM)<br />
Quality of Service in IP networks<br />
1<br />
3. Markers Pag. 1<br />
The Single Rate Three Color Marker (srTCM) can be us<strong>ed</strong> as<br />
component in a Diffserv traffic con<strong>di</strong>tioner<br />
The srTCM meters a traffic stream and marks its packets accor<strong>di</strong>ng to<br />
<strong>three</strong> traffic parameters<br />
Committ<strong>ed</strong> Information Rate (CIR) (green)<br />
Committ<strong>ed</strong> Burst Size (CBS) (yellow)<br />
and Excess Burst Size (EBS) (r<strong>ed</strong>)<br />
A packet is mark<strong>ed</strong><br />
green if it doesn't exce<strong>ed</strong> the CBS<br />
yellow if it does exce<strong>ed</strong> the CBS, but not the EBS<br />
r<strong>ed</strong> otherwise<br />
Paolo Giacomazzi
Course of Multime<strong>di</strong>a Internet (Sub-course”Reti Internet Multime<strong>di</strong>ali”), AA 2010-2011 Prof. Paolo Giacomazzi<br />
Politecnico <strong>di</strong> Milano, <strong>Dipartimento</strong> <strong>di</strong> <strong>Elettronica</strong> e Informazione, Via Ponzio, 34/5, 20133 MILANO, ITALY<br />
Single-<strong>rate</strong> <strong>three</strong>-<strong>color</strong> <strong>marker</strong> (srTCM)<br />
Quality of Service in IP networks<br />
2<br />
3. Markers Pag. 2<br />
The Meter ope<strong>rate</strong>s in one of two modes<br />
In the Color-Blind mode, the Meter assumes that the packet stream is<br />
un<strong>color</strong><strong>ed</strong><br />
In the Color-Aware mode the Meter assumes that some prece<strong>di</strong>ng<br />
entity has pre- <strong>color</strong><strong>ed</strong> the incoming packet stream so that each packet<br />
is either green, yellow, or r<strong>ed</strong><br />
The Marker (re)<strong>color</strong>s an IP packet accor<strong>di</strong>ng to the results of the<br />
Meter<br />
The <strong>color</strong> is cod<strong>ed</strong> in the DS field of the packet in a Per-Hop-Behavior<br />
specific manner<br />
This means that green, yellow and r<strong>ed</strong> traffic are treat<strong>ed</strong> <strong>di</strong>fferently in<br />
the network<br />
The specific way in which traffic is treat<strong>ed</strong> (Per Hop behavior) will be<br />
detail<strong>ed</strong> in the following<br />
Paolo Giacomazzi
Course of Multime<strong>di</strong>a Internet (Sub-course”Reti Internet Multime<strong>di</strong>ali”), AA 2010-2011 Prof. Paolo Giacomazzi<br />
Politecnico <strong>di</strong> Milano, <strong>Dipartimento</strong> <strong>di</strong> <strong>Elettronica</strong> e Informazione, Via Ponzio, 34/5, 20133 MILANO, ITALY<br />
Single-<strong>rate</strong> <strong>three</strong>-<strong>color</strong> <strong>marker</strong> (srTCM)<br />
Quality of Service in IP networks<br />
3<br />
3. Markers Pag. 3<br />
The CIR is measur<strong>ed</strong> in bytes of IP packets per second, i.e., it<br />
includes the IP header, but not link specific headers<br />
The CBS and the EBS and are measur<strong>ed</strong> in bytes<br />
The CBS and EBS must be configur<strong>ed</strong> so that at least one of them is<br />
larger than 0<br />
It is recommend<strong>ed</strong> that when the value of the CBS or the EBS is<br />
larger than 0, it is larger than or equal to the size of the largest<br />
possible IP packet in the stream<br />
Paolo Giacomazzi
Course of Multime<strong>di</strong>a Internet (Sub-course”Reti Internet Multime<strong>di</strong>ali”), AA 2010-2011 Prof. Paolo Giacomazzi<br />
Politecnico <strong>di</strong> Milano, <strong>Dipartimento</strong> <strong>di</strong> <strong>Elettronica</strong> e Informazione, Via Ponzio, 34/5, 20133 MILANO, ITALY<br />
Single-<strong>rate</strong> <strong>three</strong>-<strong>color</strong> <strong>marker</strong> (srTCM)<br />
The behavior of the Meter is specifi<strong>ed</strong> in<br />
terms of its mode and two token<br />
buckets, C and E, which both share the<br />
common <strong>rate</strong> CIR<br />
The maximum size of the token bucket<br />
C is CBS and the maximum size of the<br />
token bucket E is EBS<br />
The token buckets C and E are initially<br />
(at time 0) full, i.e., the token count Tc(0)<br />
= CBS and the token count Te(0) = EBS<br />
Thereafter, the token counts Tc and Te<br />
are updat<strong>ed</strong> CIR times per second as<br />
follows<br />
If Tc is less than CBS, Tc is<br />
increment<strong>ed</strong> by one, else<br />
if Te is less then EBS, Te is<br />
increment<strong>ed</strong> by one, else<br />
neither Tc nor Te is increment<strong>ed</strong><br />
Quality of Service in IP networks<br />
4<br />
CBS<br />
Un<strong>color</strong><strong>ed</strong><br />
flow<br />
tokens<br />
C E<br />
3. Markers Pag. 4<br />
EBS<br />
<strong>color</strong><strong>ed</strong> flow<br />
srTCM operating in the<br />
Color-blind mode<br />
Paolo Giacomazzi
Course of Multime<strong>di</strong>a Internet (Sub-course”Reti Internet Multime<strong>di</strong>ali”), AA 2010-2011 Prof. Paolo Giacomazzi<br />
Politecnico <strong>di</strong> Milano, <strong>Dipartimento</strong> <strong>di</strong> <strong>Elettronica</strong> e Informazione, Via Ponzio, 34/5, 20133 MILANO, ITALY<br />
Single-<strong>rate</strong> <strong>three</strong>-<strong>color</strong> <strong>marker</strong> (srTCM)<br />
When a packet of size B bytes<br />
arrives at time t, the following<br />
happens if the srTCM is configur<strong>ed</strong><br />
to ope<strong>rate</strong> in the Color-Blind mode:<br />
If Tc(t)-B >= 0, the packet is green<br />
and Tc is decrement<strong>ed</strong> by B down<br />
to the minimum value of 0, else<br />
if Te(t)-B >= 0, the packets is yellow<br />
and Te is decrement<strong>ed</strong> by B down<br />
to the minimum value of 0, else<br />
the packet is r<strong>ed</strong> and neither Tc nor<br />
Te is decrement<strong>ed</strong><br />
Quality of Service in IP networks<br />
5<br />
CBS<br />
Un<strong>color</strong><strong>ed</strong><br />
flow<br />
tokens<br />
C E<br />
3. Markers Pag. 5<br />
EBS<br />
<strong>color</strong><strong>ed</strong> flow<br />
srTCM operating in the<br />
Color-blind mode<br />
Paolo Giacomazzi
Course of Multime<strong>di</strong>a Internet (Sub-course”Reti Internet Multime<strong>di</strong>ali”), AA 2010-2011 Prof. Paolo Giacomazzi<br />
Politecnico <strong>di</strong> Milano, <strong>Dipartimento</strong> <strong>di</strong> <strong>Elettronica</strong> e Informazione, Via Ponzio, 34/5, 20133 MILANO, ITALY<br />
Single-<strong>rate</strong> <strong>three</strong>-<strong>color</strong> <strong>marker</strong> (srTCM)<br />
When a packet of size B bytes<br />
arrives at time t, the following<br />
happens if the srTCM is configur<strong>ed</strong><br />
to ope<strong>rate</strong> in the Color-Aware mode:<br />
If the packet has been pre<strong>color</strong><strong>ed</strong><br />
as green and Tc(t)-B >= 0, the<br />
packet is green and Tc is<br />
decrement<strong>ed</strong> by B down to the<br />
minimum value of 0, else<br />
If the packet has been pre<strong>color</strong><strong>ed</strong><br />
as green or yellow and if Te(t)-B >=<br />
0, the packets is yellow and Te is<br />
decrement<strong>ed</strong> by B down to the<br />
minimum value of 0, else<br />
the packet is r<strong>ed</strong> and neither Tc nor<br />
Te is decrement<strong>ed</strong><br />
Quality of Service in IP networks<br />
6<br />
CBS<br />
<strong>color</strong><strong>ed</strong> flow<br />
tokens<br />
C E<br />
3. Markers Pag. 6<br />
EBS<br />
<strong>color</strong><strong>ed</strong> flow<br />
srTCM operating in the<br />
Color-aware mode<br />
Paolo Giacomazzi
Course of Multime<strong>di</strong>a Internet (Sub-course”Reti Internet Multime<strong>di</strong>ali”), AA 2010-2011 Prof. Paolo Giacomazzi<br />
Politecnico <strong>di</strong> Milano, <strong>Dipartimento</strong> <strong>di</strong> <strong>Elettronica</strong> e Informazione, Via Ponzio, 34/5, 20133 MILANO, ITALY<br />
Single-<strong>rate</strong> <strong>three</strong>-<strong>color</strong> <strong>marker</strong> (srTCM)<br />
The srTCM can be us<strong>ed</strong> to mark a<br />
packet stream in a service, where<br />
<strong>di</strong>fferent, decreasing levels of<br />
assurances are given to packets<br />
which are green, yellow, or r<strong>ed</strong><br />
For example, a service may<br />
<strong>di</strong>scard all r<strong>ed</strong> packets, because<br />
they exce<strong>ed</strong><strong>ed</strong> both the committ<strong>ed</strong><br />
and excess burst sizes<br />
forward yellow packets as best<br />
effort<br />
forward green packets with a low<br />
drop probability<br />
Quality of Service in IP networks<br />
7<br />
CBS<br />
<strong>color</strong><strong>ed</strong> flow<br />
tokens<br />
C E<br />
3. Markers Pag. 7<br />
EBS<br />
<strong>color</strong><strong>ed</strong> flow<br />
srTCM operating in the<br />
Color-aware mode<br />
Paolo Giacomazzi
Course of Multime<strong>di</strong>a Internet (Sub-course”Reti Internet Multime<strong>di</strong>ali”), AA 2010-2011 Prof. Paolo Giacomazzi<br />
Politecnico <strong>di</strong> Milano, <strong>Dipartimento</strong> <strong>di</strong> <strong>Elettronica</strong> e Informazione, Via Ponzio, 34/5, 20133 MILANO, ITALY<br />
<strong>Two</strong>-<strong>rate</strong> <strong>three</strong>-<strong>color</strong> <strong>marker</strong> (trTCM)<br />
Quality of Service in IP networks<br />
8<br />
3. Markers Pag. 8<br />
The trTCM meters an IP packet stream and marks its packets bas<strong>ed</strong><br />
on two <strong>rate</strong>s<br />
Peak Information Rate (PIR) and<br />
Committ<strong>ed</strong> Information Rate (CIR)<br />
and their associat<strong>ed</strong> burst sizes to be either<br />
Green<br />
Yellow<br />
R<strong>ed</strong><br />
A packet is mark<strong>ed</strong> r<strong>ed</strong> if it exce<strong>ed</strong>s the PIR<br />
Otherwise it is mark<strong>ed</strong> either yellow or green depen<strong>di</strong>ng on whether it<br />
exce<strong>ed</strong>s or doesn't exce<strong>ed</strong> the CIR<br />
Paolo Giacomazzi
Course of Multime<strong>di</strong>a Internet (Sub-course”Reti Internet Multime<strong>di</strong>ali”), AA 2010-2011 Prof. Paolo Giacomazzi<br />
Politecnico <strong>di</strong> Milano, <strong>Dipartimento</strong> <strong>di</strong> <strong>Elettronica</strong> e Informazione, Via Ponzio, 34/5, 20133 MILANO, ITALY<br />
<strong>Two</strong>-<strong>rate</strong> <strong>three</strong>-<strong>color</strong> <strong>marker</strong> (trTCM)<br />
Quality of Service in IP networks<br />
9<br />
3. Markers Pag. 9<br />
The trTCM is configur<strong>ed</strong> by setting its mode (<strong>color</strong>-blind or <strong>color</strong>aware)<br />
and by assigning values to four traffic parameters:<br />
a Peak Information Rate (PIR) and its associat<strong>ed</strong> Peak Burst Size (PBS)<br />
a Committ<strong>ed</strong> Information Rate (CIR) and its associat<strong>ed</strong> Committ<strong>ed</strong> Burst<br />
Size (CBS)<br />
The PIR and CIR are measur<strong>ed</strong> in bytes of IP packets per second,<br />
i.e., it includes the IP header, but not link specific headers<br />
The PIR must be equal to or greater than the CIR<br />
The PBS and the CBS and are measur<strong>ed</strong> in bytes and both of them<br />
must be configur<strong>ed</strong> to be greater than 0<br />
It is recommend<strong>ed</strong> that they be configur<strong>ed</strong> to be equal to or greater<br />
than the size of the largest possible IP packet in the stream<br />
Paolo Giacomazzi
Course of Multime<strong>di</strong>a Internet (Sub-course”Reti Internet Multime<strong>di</strong>ali”), AA 2010-2011 Prof. Paolo Giacomazzi<br />
Politecnico <strong>di</strong> Milano, <strong>Dipartimento</strong> <strong>di</strong> <strong>Elettronica</strong> e Informazione, Via Ponzio, 34/5, 20133 MILANO, ITALY<br />
<strong>Two</strong>-<strong>rate</strong> <strong>three</strong>-<strong>color</strong> <strong>marker</strong> (trTCM)<br />
The behavior of the Meter is<br />
specifi<strong>ed</strong> in terms of its mode and<br />
two token buckets, P and C, with<br />
<strong>rate</strong>s PIR and CIR, respectively<br />
The maximum size of the token<br />
bucket P is PBS and the maximum<br />
size of the token bucket C is CBS<br />
The token buckets P and C are<br />
initially (at time 0) full, i.e., the token<br />
count Tp(0) = PBS and the token<br />
count Tc(0) = CBS<br />
Thereafter, the token count Tp is<br />
increment<strong>ed</strong> by one PIR times per<br />
second up to PBS<br />
The token count Tc is increment<strong>ed</strong><br />
by one CIR times per second up to<br />
CBS<br />
Quality of Service in IP networks<br />
10<br />
Tokens at<br />
<strong>rate</strong> CIR<br />
CBS<br />
Un<strong>color</strong><strong>ed</strong><br />
flow<br />
C P<br />
3. Markers Pag. 10<br />
Tokens at<br />
<strong>rate</strong> PIR<br />
PBS<br />
<strong>color</strong><strong>ed</strong> flow<br />
trTCM operating in the<br />
Color-blind mode<br />
Paolo Giacomazzi
Course of Multime<strong>di</strong>a Internet (Sub-course”Reti Internet Multime<strong>di</strong>ali”), AA 2010-2011 Prof. Paolo Giacomazzi<br />
Politecnico <strong>di</strong> Milano, <strong>Dipartimento</strong> <strong>di</strong> <strong>Elettronica</strong> e Informazione, Via Ponzio, 34/5, 20133 MILANO, ITALY<br />
<strong>Two</strong>-<strong>rate</strong> <strong>three</strong>-<strong>color</strong> <strong>marker</strong> (trTCM)<br />
When a packet of size B bytes<br />
arrives at time t, the following<br />
happens if the trTCM is configur<strong>ed</strong><br />
to ope<strong>rate</strong> in the Color-Blind mode:<br />
If Tp(t)-B < 0, the packet is r<strong>ed</strong>, else<br />
if Tc(t)-B < 0, the packet is yellow<br />
and Tp is decrement<strong>ed</strong> by B, else<br />
the packet is green and both Tp and<br />
Tc are decrement<strong>ed</strong> by B<br />
Quality of Service in IP networks<br />
11<br />
Tokens at<br />
<strong>rate</strong> CIR<br />
CBS<br />
Un<strong>color</strong><strong>ed</strong><br />
flow<br />
C P<br />
3. Markers Pag. 11<br />
Tokens at<br />
<strong>rate</strong> PIR<br />
PBS<br />
<strong>color</strong><strong>ed</strong> flow<br />
trTCM operating in the<br />
Color-blind mode<br />
Paolo Giacomazzi
Course of Multime<strong>di</strong>a Internet (Sub-course”Reti Internet Multime<strong>di</strong>ali”), AA 2010-2011 Prof. Paolo Giacomazzi<br />
Politecnico <strong>di</strong> Milano, <strong>Dipartimento</strong> <strong>di</strong> <strong>Elettronica</strong> e Informazione, Via Ponzio, 34/5, 20133 MILANO, ITALY<br />
<strong>Two</strong>-<strong>rate</strong> <strong>three</strong>-<strong>color</strong> <strong>marker</strong> (trTCM)<br />
When a packet of size B bytes<br />
arrives at time t, the following<br />
happens if the trTCM is configur<strong>ed</strong><br />
to ope<strong>rate</strong> in the Color-Aware mode:<br />
If the packet has been pre<strong>color</strong><strong>ed</strong><br />
as r<strong>ed</strong> or if Tp(t)-B < 0, the packet is<br />
r<strong>ed</strong>, else<br />
if the packet has been pre<strong>color</strong><strong>ed</strong><br />
as yellow or if Tc(t)-B < 0, the<br />
packet is yellow and Tp is<br />
decrement<strong>ed</strong> by B, else<br />
the packet is green and both Tp and<br />
Tc are decrement<strong>ed</strong> by B<br />
Quality of Service in IP networks<br />
12<br />
Tokens at<br />
<strong>rate</strong> CIR<br />
CBS<br />
<strong>color</strong><strong>ed</strong> flow<br />
C P<br />
3. Markers Pag. 12<br />
Tokens at<br />
<strong>rate</strong> PIR<br />
PBS<br />
<strong>color</strong><strong>ed</strong> flow<br />
trTCM operating in the<br />
Color-aware mode<br />
Paolo Giacomazzi
Course of Multime<strong>di</strong>a Internet (Sub-course”Reti Internet Multime<strong>di</strong>ali”), AA 2010-2011 Prof. Paolo Giacomazzi<br />
Politecnico <strong>di</strong> Milano, <strong>Dipartimento</strong> <strong>di</strong> <strong>Elettronica</strong> e Informazione, Via Ponzio, 34/5, 20133 MILANO, ITALY<br />
<strong>Two</strong>-<strong>rate</strong> <strong>three</strong>-<strong>color</strong> <strong>marker</strong> (trTCM)<br />
Cumulative output traffic<br />
Rate PIR<br />
PBS/PIR<br />
Rate CIR<br />
Quality of Service in IP networks<br />
13<br />
t(s)<br />
Tokens at<br />
<strong>rate</strong> CIR<br />
CBS<br />
Un<strong>color</strong><strong>ed</strong><br />
flow<br />
C P<br />
3. Markers Pag. 13<br />
Tokens at<br />
<strong>rate</strong> PIR<br />
PBS<br />
<strong>color</strong><strong>ed</strong> flow<br />
trTCM operating in the<br />
Color-blind mode<br />
Paolo Giacomazzi