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Re: Question on LMP.
Hi Jonathan,
Thanks for the quick response. Please see my comments inline.
Manoj
Jonathan Lang wrote:
>
> Manoj,
> Please see inline.
>
> Thanks,
> Jonathan
>
> > -----Original Message-----
> > From: Manoj Sontakke [mailto:manojs@sasken.com]
> > Sent: Thursday, April 11, 2002 7:02 AM
> > To: ccamp@ops.ietf.org
> > Subject: Question on LMP.
> >
> >
> > Hi,
> >
> > I have two questions on LMP.
> >
> > --------------------------------------------------------------
> > -----------------------------
> > Q1. Control Channel Question
> >
> > Assuming a configuration as shown.
> >
> >
> > ----------------- -----------------
> > | | | |
> > | if1|---------------|if1 |
> > | if2|---------------|if2 |
> > | OXC 1 | | OXC 2 |
> > | d1|---------------|d1 |
> > | d2|---------------|d2 |
> > -----------------
> > -----------------
> >
> >
> > I have two OXCs connected by four links. Consider d1, d2 are configured
> > to carry data and if1 and if2 are configured to carry control data ( LMP
> > messages and RSVP and OSPF messages).
> >
> > The LMP document defines control channels with an unique identifier (
> > control channel identifier ) between the negibouring nodes.
> > So also, the LMP messages are IP encapsulated.
> >
> > Now, I have a couple of questions
> >
> > 1. Is there any association between the LMP control channels to the
> > physical interfaces( if1, if2). Because all the IP packets are routed on
> > the physical interfaces according to the routing table. The control
> > channel messages like ( config and configAck etc.. ) can go on the any
> > physical interface which is decided by the routing table.
> >
> > In such case, are the control channels a pure logical concept or do they
> > have any physical interface significance & correlation [ mapping between
> > control channles ( ccid ) and interfaces ( if1 and if2 )] ?
> Control channels are associated with interfaces.
Manoj-> The draft does not say so explicitly. Besides, all the LMP
messages are IP encoded. So the routing table decides the outgoing
interface for sending the LMP messages (any packet for that matter)
depending upon the destination IP address.
So is it possible to make such an association between the LMP control
channel and a physical interface (though it is desirable)? Are we
deviating from the standard IP implementation ?
>
> >
> > --------------------------------------------------------------
> > -----------------------------
> > Q2. MessageId question
> >
> > In the LMP document, the config Message & config ack messages are
> > defined as
> >
> > <configMessage> ::= <common header> <LOCAL_CCID> <MESSGAE_ID>
> > <LOCAL_NODE_ID> <CONFIG>
> >
> > <configAckMessage> ::= <common header> <LOCAL_CCID>
> > <LOCAL_NODE_ID> <REMOTE_CCID>
> > <MESSAGE_ID_ACK> <REMOTE_NODE_ID>
> >
> > Assume the following sequence.
> >
> > ConfigMessage
> > OXC1 ----------------------------------> OXC2
> >
> > ConfigMessage
> > OXC1 ----------------------------------> OXC2
> >
> > ConfigMessage
> > OXC1 ----------------------------------> OXC2
> >
> > ConfigAckMessage
> > OXC1 <---------------------------------- OXC2
> >
> > On the OXC1 when the configAck Message is received then the OXC1 can
> > come to know that the config Message has been received by the OXC2 and
> > it can identify that it received the ack for a LOCAL_CCID.
> > Any configAck
> > recevied will result in bringing that control channel UP.
> >
> > So how does the <MESSAGE_ID> and <MESSAGE_ID_ACK> helps improve the
> > message realiability ?
> Message_ID helps identify new Config/ConfigAck messages for the same control
> channel.
Manoj-> Isn't the CCID enough ?
>
> >
> > --------------------------------------------------------------
> > ---------------------------
> >
> > Any comments in this regard will be appreciated.
> >
> > Thanks,
> > Manoj
> >