RE: Clarifications with RFC 3077

"William StanisLaus" <[email protected]> Fri, 1 Nov 2002 17:58:20 +0530
Newsgroups gmane.ietf.udlr,gmane.spam.detected
Message-ID <3DC27364.000001.03964@williams>
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Hi Emmanuel,=0D
=0D
Thanks for your clarification.=0D
>For scenario 2, it is more of an implementation issue and there are many=
=0D
>question marks: Does the IP layer see both physical interfaces as a=0D
>unique logical interface ? Is your receiver a router or a bridge ?...=0D
=0D
Yeah the IP Layer see both physical interfaces as one unique logial
interface in our RCS System. Our receiver is a router.=0D
=0D
I have few more doubts Regarding Feeder unidirectional MAC Address=0D
=0D
In our RCS System we don't get Feeder MAC address in the MPEG-2 packets, =
it
contains only the Destination MAC address. So how do we get the Feeder MA=
C
address, is there any generic procedure for UDLR??=0D
=0D
Section 7.3=0D
"   The FUMAC value for an active feed is needed for the operation of=0D
   this protocol.  However, the method of discovery of this value is not=0D
   specified here.=0D
=0D
"=0D
=0D
Thanks in advance.=0D
=0D
Regards,=0D
William.=0D
=0D
 =0D
-------Original Message-------=0D
 =0D
From: Emmanuel Duros=0D
Date: Wednesday, October 30, 2002 10:25:15 PM=0D
To: William StanisLaus=0D
Cc: udlr=0D
Subject: RE: Clarifications with RFC 3077=0D
 =0D
William,=0D
=0D
On Wed, 2002-10-30 at 08:29, William StanisLaus wrote:=0D
> Hi Emmanuel Duros,=0D
> Good Day. Thanks for your Clarifications.=0D
> =0D
> Regarding Q 2)=0D
> =0D
> Yep, Our Return Link is unidirectional, and TX and RX are 2 different =0D
> interfaces.=0D
> =0D
> My Clarification now might be silly, but just to doubt check my
understanding =0D
> :)=0D
> =0D
> RCS System with both TX and RX port.=0D
> =0D
> Scenario 1: RCS Sytem sends/response to Feeder (Send Only). The packet =
is =0D
> Encapsulated and based on the Routing table it chooses Tx Port(Return
Link) or =0D
> RCS System bi-directional interface targeting Feeder bidirectional
interface.=0D
> In Case if Tx Port is selected, there should be a Gateway which receive=
s
the =0D
> Encapsulated packet from RCS System and forwards to the feeder
bidirectional =0D
> interface, just IP Forward.=0D
>=0D
> Scenaio 2: RCS System sends/response to Feeder( Receive capable feeder)=
=2E
The =0D
> packet is not Encapsulated, just sends via the TX port(Return Link) to =
the
=0D
> Feeder.=0D
> =0D
> so Encapsulation Decisions are taken based on the DTCP table, "feeder t=
ype
=0D
> information" in the RCS System..=0D
> =0D
> Note: All the Scenarios are not IP forwarding=0D
> =0D
=0D
My understanding is that the receiver has 2 physical interfaces: a=0D
receive-only interface and a distinct interface used for the return link=0D
(RCS, RTC, or whatever !). The decision for routing IP traffic is taken=0D
at IP layer using routing tables and is *not* related to the type of=0D
feed contained in the DTCP announcement.=0D
=0D
Any IP packet sent through the receive-only interface is encapsulated in=0D
GRE packet and sent to the feed via the return link. The feed (send-only=0D
or receive-capable) that support UDLR will decapsulate the incoming GRE=0D
packet (from whatever interface) and processes the payload as coming=0D
from the "satellite" interface.=0D
=0D
For scenario 2, it is more of an implementation issue and there are many=0D
question marks: Does the IP layer see both physical interfaces as a=0D
unique logical interface ? Is your receiver a router or a bridge ?...=0D
=0D
> Thanks and Best Regards,=0D
> William StanisLaus.=0D
=0D
Emmanuel=0D
=0D
> =0D
> >=3D=3D=3D=3D=3D Original Message From Emmanuel Duros <emmanuel.duros@u=
dcast.com>
=3D=3D=3D=3D=3D=0D
> >Hello William,=0D
> >=0D
> >On Tue, 2002-10-29 at 12:01, William StanisLaus wrote:=0D
> >> Hi all,=0D
> >>=0D
> >> I am a newbee to UDLR technology. I have few clarifications with RFC=
 =0D
> 3077.=0D
> >>=0D
> >> Can you help me in understanding the concept.=0D
> >> here we go.....=0D
> >>=0D
> >> 1)=0D
> >>=0D
> >> In Section 7=0D
> >> "The number of feeds is expected to be relatively small (Section 3),=
=0D
> >> so at every feed the list of all feeds is configured manually."=0D
> >>=0D
> >> In Section 7.1=0D
> >> When Feed multicasts the DTCP Hello Message, it passes the Feed Type=
=0D
> >>=0D
> >> i.e.=0D
> >> F (1 bit): bit indicating the type of feed:=0D
> >> 0 =3D Send-only feed=0D
> >> 1 =3D Receive-capable feed=0D
> >>=0D
> >>=0D
> >> So the Reciever can maintain the Feed type in the DTCP routing table=
=2E=0D
> >> In Such cases,=0D
> >> for Scenario 2: "A receiver can send a broadcast/multicast packet on
the=0D
> >> link to all nodes (point-to-multipoint)"=0D
> >>=0D
> >> Section 6.2.2 (3)=0D
> >> As of now, Receiver sends packets to be broadcasted/multicasted to t=
he =0D
> default=0D
> >> feed and the default feed broadcast/multicast the packet to the othe=
r
Feed =0D
> &=0D
> >> Receivers.=0D
> >>=0D
> >>=0D
> >> Clarification :-=0D
> >>=0D
> >> When the Receiver maintains the Feed types, which is dynamic at any
moment,=0D
> >> why Receiver is not multicasting to all the Feeds which are Send onl=
y?=0D
> >=0D
> >The main reason I see is that it would be costly in term of bandwidth=0D
> >for the receiving site. A copy of every multicast packet would have to=
=0D
> >be tunneled from the receiver to each Send-only feed. It can get reall=
y=0D
> >bad for the receiver if it has a low speed return link such as GSM or=0D
> >RTC.=0D
> >=0D
> >It is easier for the operator to set up high speed links between the=0D
> >feeds and let them make the duplication of packets...=0D
> >=0D
> >> It can also have a default Feed which forwards the packet to all
receivers =0D
> and=0D
> >> receive capable Feeds.=0D
> >>=0D
> >>=0D
> >> The clarification is because, we have the overhead of encapulation a=
t
the=0D
> >> receiver side and sending to the default feed which decapulate and
again=0D
> >> encapulate to send to Send only Feeds. Also in the Feeds the list of=
=0D
> >> other feeds are manually configured i.e. Static. Might be broken at =
any
=0D
> time.=0D
> >>=0D
> >>=0D
> >> 2)=0D
> >>=0D
> >> In the RFC 3077 which explaines about the Feeds , i.e. Send only and=
 =0D
> Recieve=0D
> >> capable Feeds. But for receivers it is always targeted as Receive on=
ly.
=0D
> Just=0D
> >> imagine a RCST with send capable receivers i.e. which has both Tx an=
d
Rx =0D
> port.=0D
> >>=0D
> >> What are the configurations in the UDLR if the receiver happens to b=
e
send=0D
> >> capable.=0D
> >>=0D
> >=0D
> >The receiver you are describing is pretty much similar to a receiver=0D
> >whose return link is unidirectional. Am I right ? It seems the TX and =
RX=0D
> >are 2 differents interfaces...=0D
> >=0D
> >This situation can be handled by UDLR although RFC 3077 says the=0D
> >receiver needs a bidirectional interface to send GRE to the feed. In=0D
> >fact, as long as the return link can carry IP datagrams from the=0D
> >receiver to the feed, the UDLR protocol will work. We've been using so=
me=0D
> >DVB-RCS systems with UDLR and it works pretty well.=0D
> >=0D
> >=0D
> >>=0D
> >>=0D
> >> Thanks and Best Regards,=0D
> >> William StanisLaus.=0D
> >>=0D
> >> _______________________________________________=0D
> >> UDLR mailing list=0D
> >> [email protected]=0D
> >> http://www.udcast.com/mailman/listinfo/udlr=0D
> >=0D
> >Regards,=0D
> >>=0D
> >--=0D
> >Emmanuel Duros http://www.udcast.com=0D
> >2455 Route des Dolines BP355 | Tel : +33 (0)4 93 00 16 60=0D
> >06906 Sophia Antipolis France | Fax : +33 (0)4 93 00 16 61=0D
> > ** Full IP over Broadcast Media **=0D
> >=0D
> >_______________________________________________=0D
> >UDLR mailing list=0D
> &gt;[email protected]=0D
> >http://www.udcast.com/mailman/listinfo/udlr=0D
> =0D
> =0D
-- =0D
Emmanuel Duros http://www.udcast.com=0D
2455 Route des Dolines BP355 | Tel : +33 (0)4 93 00 16 60=0D
06906 Sophia Antipolis France | Fax : +33 (0)4 93 00 16 61=0D
** Full IP over Broadcast Media **=0D
=0D
_______________________________________________=0D
UDLR mailing list=0D
[email protected]=0D
http://www.udcast.com/mailman/listinfo/udlr=0D
=2E=20
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<DIV>Hi Emmanuel,</DIV>
<DIV>&nbsp;</DIV>
<DIV>Thanks for your clarification.</DIV>
<DIV>&gt;For scenario 2, it is more of an implementation issue and there =
are many<BR>&gt;question marks: Does the IP layer see both physical inter=
faces as a<BR>&gt;unique logical interface ? Is your receiver a router or=
 a bridge ?...</DIV>
<DIV>&nbsp;</DIV>
<DIV>Yeah the IP Layer see both physical interfaces as one unique logial =
interface&nbsp;in&nbsp;our RCS System. Our receiver is a router.</DIV>
<DIV>&nbsp;</DIV>
<DIV>I have few more doubts Regarding Feeder unidirectional MAC Address</=
DIV>
<DIV>&nbsp;</DIV>
<DIV>In our RCS System we don't get Feeder MAC address in the MPEG-2 pack=
ets, it contains only the Destination MAC address. So how do we get the F=
eeder MAC address, is there any generic procedure for UDLR??</DIV>
<DIV>&nbsp;</DIV>
<P class=3DMsoPlainText style=3D"MARGIN: 0in 0in 0pt"><SPAN style=3D"mso-=
fareast-font-family: 'MS Mincho'"><FONT size=3D2><FONT color=3D#000000><F=
ONT face=3D"Courier New"><SPAN style=3D"mso-spacerun: yes">Section 7.3</S=
PAN></FONT></FONT></FONT></SPAN></P>
<P class=3DMsoPlainText style=3D"MARGIN: 0in 0in 0pt"><SPAN style=3D"mso-=
fareast-font-family: 'MS Mincho'"><FONT size=3D2><FONT color=3D#000000><F=
ONT face=3D"Courier New"><SPAN style=3D"mso-spacerun: yes">"&nbsp;&nbsp; =
</SPAN>The FUMAC value for an active feed is needed for the operation of<=
BR><SPAN style=3D"mso-spacerun: yes">&nbsp;&nbsp; </SPAN>this protocol.<S=
PAN style=3D"mso-spacerun: yes">&nbsp; </SPAN>However, the method of disc=
overy of this value is not<BR><SPAN style=3D"mso-spacerun: yes">&nbsp;&nb=
sp; </SPAN>specified here.</FONT></FONT></FONT><BR></P>
<DIV></SPAN>"<BR></DIV>
<DIV>Thanks in advance.</DIV>
<DIV>&nbsp;</DIV>
<DIV>Regards,</DIV>
<DIV>William.</DIV>
<DIV><BR>&nbsp;</DIV>
<DIV id=3DIncrediOriginalMessage><I>-------Original Message-------</I></D=
IV>
<DIV>&nbsp;</DIV>
<DIV id=3Dreceivestrings>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt" <i><B>From:</B></I> <A href=3D"m=
ailto:[email protected]">Emmanuel Duros</A></DIV>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt" <i><B>Date:</B></I> Wednesday, O=
ctober 30, 2002 10:25:15 PM</DIV>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt" <i><B>To:</B></I> <A href=3D"mai=
lto:[email protected]">William StanisLaus</A></DIV>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt" <i><B>Cc:</B></I> <A href=3D"mai=
lto:[email protected]">udlr</A></DIV>
<DIV dir=3Dltr style=3D"FONT-SIZE: 11pt" <i><B>Subject:</B></I> RE: Clari=
fications with RFC 3077</DIV></DIV>
<DIV>&nbsp;</DIV>William,<BR><BR>On Wed, 2002-10-30 at 08:29, William Sta=
nisLaus wrote:<BR>&gt; Hi Emmanuel Duros,<BR>&gt; Good Day. Thanks for yo=
ur Clarifications.<BR>&gt; <BR>&gt; Regarding Q 2)<BR>&gt; <BR>&gt; Yep, =
Our Return Link is unidirectional, and TX and RX are 2 different <BR>&gt;=
 interfaces.<BR>&gt; <BR>&gt; My Clarification now might be silly, but ju=
st to doubt check my understanding <BR>&gt; :)<BR>&gt; <BR>&gt; RCS Syste=
m with both TX and RX port.<BR>&gt; <BR>&gt; Scenario 1: RCS Sytem sends/=
response to Feeder (Send Only). The packet is <BR>&gt; Encapsulated and b=
ased on the Routing table it chooses Tx Port(Return Link) or <BR>&gt; RCS=
 System bi-directional interface targeting Feeder bidirectional interface=
=2E<BR>&gt; In Case if Tx Port is selected, there should be a Gateway whi=
ch receives the <BR>&gt; Encapsulated packet from RCS System and forwards=
 to the feeder bidirectional <BR>&gt; interface, just IP Forward.<BR>&gt;=
<BR>&gt; Scenaio 2: RCS System sends/response to Feeder( Receive capable =
feeder). The <BR>&gt; packet is not Encapsulated, just sends via the TX p=
ort(Return Link) to the <BR>&gt; Feeder.<BR>&gt; <BR>&gt; so Encapsulatio=
n Decisions are taken based on the DTCP table, "feeder type <BR>&gt; info=
rmation" in the RCS System..<BR>&gt; <BR>&gt; Note: All the Scenarios are=
 not IP forwarding<BR>&gt; <BR><BR>My understanding is that the receiver =
has 2 physical interfaces: a<BR>receive-only interface and a distinct int=
erface used for the return link<BR>(RCS, RTC, or whatever !). The decisio=
n for routing IP traffic is taken<BR>at IP layer using routing tables and=
 is *not* related to the type of<BR>feed contained in the DTCP announceme=
nt.<BR><BR>Any IP packet sent through the receive-only interface is encap=
sulated in<BR>GRE packet and sent to the feed via the return link. The fe=
ed (send-only<BR>or receive-capable) that support UDLR will decapsulate t=
he incoming GRE<BR>packet (from whatever interface) and processes the pay=
load as coming<BR>from the "satellite" interface.<BR><BR>For scenario 2, =
it is more of an implementation issue and there are many<BR>question mark=
s: Does the IP layer see both physical interfaces as a<BR>unique logical =
interface ? Is your receiver a router or a bridge ?...<BR><BR>&gt; Thanks=
 and Best Regards,<BR>&gt; William StanisLaus.<BR><BR>Emmanuel<BR><BR>&gt=
; <BR>&gt; &gt;=3D=3D=3D=3D=3D Original Message From Emmanuel Duros &lt;<=
A href=3D"mailto:[email protected]">[email protected]</A>=
&gt; =3D=3D=3D=3D=3D<BR>&gt; &gt;Hello William,<BR>&gt; &gt;<BR>&gt; &gt;=
On Tue, 2002-10-29 at 12:01, William StanisLaus wrote:<BR>&gt; &gt;&gt; H=
i all,<BR>&gt; &gt;&gt;<BR>&gt; &gt;&gt; I am a newbee to UDLR technology=
=2E I have few clarifications with RFC <BR>&gt; 3077.<BR>&gt; &gt;&gt;<BR=
>&gt; &gt;&gt; Can you help me in understanding the concept.<BR>&gt; &gt;=
&gt; here we go.....<BR>&gt; &gt;&gt;<BR>&gt; &gt;&gt; 1)<BR>&gt; &gt;&gt=
;<BR>&gt; &gt;&gt; In Section 7<BR>&gt; &gt;&gt; "The number of feeds is =
expected to be relatively small (Section 3),<BR>&gt; &gt;&gt; so at every=
 feed the list of all feeds is configured manually."<BR>&gt; &gt;&gt;<BR>=
&gt; &gt;&gt; In Section 7.1<BR>&gt; &gt;&gt; When Feed multicasts the DT=
CP Hello Message, it passes the Feed Type<BR>&gt; &gt;&gt;<BR>&gt; &gt;&g=
t; i.e.<BR>&gt; &gt;&gt; F (1 bit): bit indicating the type of feed:<BR>&=
gt; &gt;&gt; 0 =3D Send-only feed<BR>&gt; &gt;&gt; 1 =3D Receive-capable =
feed<BR>&gt; &gt;&gt;<BR>&gt; &gt;&gt;<BR>&gt; &gt;&gt; So the Reciever c=
an maintain the Feed type in the DTCP routing table.<BR>&gt; &gt;&gt; In =
Such cases,<BR>&gt; &gt;&gt; for Scenario 2: "A receiver can send a broad=
cast/multicast packet on the<BR>&gt; &gt;&gt; link to all nodes (point-to=
-multipoint)"<BR>&gt; &gt;&gt;<BR>&gt; &gt;&gt; Section 6.2.2 (3)<BR>&gt;=
 &gt;&gt; As of now, Receiver sends packets to be broadcasted/multicasted=
 to the <BR>&gt; default<BR>&gt; &gt;&gt; feed and the default feed broad=
cast/multicast the packet to the other Feed <BR>&gt; &amp;<BR>&gt; &gt;&g=
t; Receivers.<BR>&gt; &gt;&gt;<BR>&gt; &gt;&gt;<BR>&gt; &gt;&gt; Clarific=
ation :-<BR>&gt; &gt;&gt;<BR>&gt; &gt;&gt; When the Receiver maintains th=
e Feed types, which is dynamic at any moment,<BR>&gt; &gt;&gt; why Receiv=
er is not multicasting to all the Feeds which are Send only?<BR>&gt; &gt;=
<BR>&gt; &gt;The main reason I see is that it would be costly in term of =
bandwidth<BR>&gt; &gt;for the receiving site. A copy of every multicast p=
acket would have to<BR>&gt; &gt;be tunneled from the receiver to each Sen=
d-only feed. It can get really<BR>&gt; &gt;bad for the receiver if it has=
 a low speed return link such as GSM or<BR>&gt; &gt;RTC.<BR>&gt; &gt;<BR>=
&gt; &gt;It is easier for the operator to set up high speed links between=
 the<BR>&gt; &gt;feeds and let them make the duplication of packets...<BR=
>&gt; &gt;<BR>&gt; &gt;&gt; It can also have a default Feed which forward=
s the packet to all receivers <BR>&gt; and<BR>&gt; &gt;&gt; receive capab=
le Feeds.<BR>&gt; &gt;&gt;<BR>&gt; &gt;&gt;<BR>&gt; &gt;&gt; The clarific=
ation is because, we have the overhead of encapulation at the<BR>&gt; &gt=
;&gt; receiver side and sending to the default feed which decapulate and =
again<BR>&gt; &gt;&gt; encapulate to send to Send only Feeds. Also in the=
 Feeds the list of<BR>&gt; &gt;&gt; other feeds are manually configured i=
=2Ee. Static. Might be broken at any <BR>&gt; time.<BR>&gt; &gt;&gt;<BR>&=
gt; &gt;&gt;<BR>&gt; &gt;&gt; 2)<BR>&gt; &gt;&gt;<BR>&gt; &gt;&gt; In the=
 RFC 3077 which explaines about the Feeds , i.e. Send only and <BR>&gt; R=
ecieve<BR>&gt; &gt;&gt; capable Feeds. But for receivers it is always tar=
geted as Receive only. <BR>&gt; Just<BR>&gt; &gt;&gt; imagine a RCST with=
 send capable receivers i.e. which has both Tx and Rx <BR>&gt; port.<BR>&=
gt; &gt;&gt;<BR>&gt; &gt;&gt; What are the configurations in the UDLR if =
the receiver happens to be send<BR>&gt; &gt;&gt; capable.<BR>&gt; &gt;&gt=
;<BR>&gt; &gt;<BR>&gt; &gt;The receiver you are describing is pretty much=
 similar to a receiver<BR>&gt; &gt;whose return link is unidirectional. A=
m I right ? It seems the TX and RX<BR>&gt; &gt;are 2 differents interface=
s...<BR>&gt; &gt;<BR>&gt; &gt;This situation can be handled by UDLR altho=
ugh RFC 3077 says the<BR>&gt; &gt;receiver needs a bidirectional interfac=
e to send GRE to the feed. In<BR>&gt; &gt;fact, as long as the return lin=
k can carry IP datagrams from the<BR>&gt; &gt;receiver to the feed, the U=
DLR protocol will work. We've been using some<BR>&gt; &gt;DVB-RCS systems=
 with UDLR and it works pretty well.<BR>&gt; &gt;<BR>&gt; &gt;<BR>&gt; &g=
t;&gt;<BR>&gt; &gt;&gt;<BR>&gt; &gt;&gt; Thanks and Best Regards,<BR>&gt;=
 &gt;&gt; William StanisLaus.<BR>&gt; &gt;&gt;<BR>&gt; &gt;&gt; _________=
______________________________________<BR>&gt; &gt;&gt; UDLR mailing list=
<BR>&gt; &gt;&gt; <A href=3D"mailto:[email protected]">[email protected]</A><=
BR>&gt; &gt;&gt; <A href=3D"http://www.udcast.com/mailman/listinfo/udlr">=
http://www.udcast.com/mailman/listinfo/udlr</A><BR>&gt; &gt;<BR>&gt; &gt;=
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