[j-nsp] packet flow

[Janto Cin]

Yes, thank you.

----- Original Message -----
From: "Gary Tate" <gtate at juniper.net>
To: "Janto Cin" <jantocin at datacomm.co.id>
Cc: <juniper-nsp at puck.nether.net>; "Gary Tate" <gtate at juniper.net>; "Steve
Holman" <sholman at juniper.net>
Sent: Friday, March 05, 2004 5:43 PM
Subject: Re: [j-nsp] packet flow


> This is not entirely easy to say.  But in general yes.  J-Cells in fpc
> memory are data cells.  Encaps and headers are built by the system
> depending on user configuration etc.  For example TOX bits in the
> header will be rewritten depending on COS config. Is this what you are
> asking?
> Gary
>
> On Mar 5, 2004, at 1:39 AM, Janto Cin wrote:
>
> > Is the notification and result cell only consist of header?
> > And the J-cell packet consist of payload?
> > TIA,
> > Janto
> > ----- Original Message -----
> > From: "Steve Holman" <sholman at juniper.net>
> > To: "Janto Cin" <jantocin at datacomm.co.id>;
> > <juniper-nsp at puck.nether.net>
> > Sent: Thursday, March 04, 2004 12:33 PM
> > Subject: RE: [j-nsp] packet flow
> >
> >
> > Yes.  The packets are buffered in the memory on the FPCs while route
> > lookup determines the nexthop.  Once the nexthop for a given packet is
> > determined, the ASIC collected the J-cells from memory, reassembles the
> > packet and forwards it to the egress port.
> >
> > Make sense?
> >
> > Cheers,
> > Steve
> >
> >> -----Original Message-----
> >> From: Janto Cin [mailto:jantocin at datacomm.co.id]
> >> Sent: Wednesday, March 03, 2004 9:12 PM
> >> To: Steve Holman; juniper-nsp at puck.nether.net
> >> Subject: Re: [j-nsp] packet flow
> >> Importance: High
> >>
> >>
> >> Hi Steve,
> >> Is that mean after packets are sent across all FPCs then
> >> the router gather all "sprayed" J-cells from all FPCs to
> >> reassembly the packet again? Thanks, Janto
> >> ----- Original Message -----
> >> From: "Steve Holman" <sholman at juniper.net>
> >> To: "Janto Cin" <jantocin at datacomm.co.id>;
> >> <juniper-nsp at puck.nether.net>
> >> Sent: Thursday, March 04, 2004 12:02 PM
> >> Subject: RE: [j-nsp] packet flow
> >>
> >>
> >> Hi Janto,
> >>
> >> The J-cells are sent to the FPCs for packet buffering prior
> >> to retransmission out the egress port.  Once the packets are
> >> ready for retransmission they are reassembled into their
> >> original form and content with the exception of the link
> >> layer header, which is added after the packet is reassembled.
> >> The packet is then sent out the egress port.
> >>
> >> As you note, packets are sent or "sprayed" across all FPCs in
> >> a round-robin fashion.  Once the ASIC has finished one round
> >> it begins all over again, overwriting any previous packets
> >> stored in memory.  However, these previous stored packets
> >> have already "left the building" so it's not a problem
> >> overwriting them.
> >>
> >> HTH,
> >> Steve
> >>
> >>> -----Original Message-----
> >>> From: juniper-nsp-bounces at puck.nether.net
> >>> [mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of Janto Cin
> >>> Sent: Wednesday, March 03, 2004 8:08 PM
> >>> To: juniper-nsp at puck.nether.net
> >>> Subject: [j-nsp] packet flow
> >>>
> >>>
> >>> Hi All,
> >>>
> >>> Just read the packet flow section in Sybex JNCIA book and curious
> >>> about why the Inbound DBM ASIC have to send the packet's J-cells to
> >>> all FPCs in the router on a round-robin basis? After done that, are
> >>> the J-cells in the shared memory pool deleted? Thanks. -Janto
> >>>
> >>> _______________________________________________
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> >>>
> >>
> >>
> >
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