[j-nsp] packet flowgtate@juniper.net

[Gary Tate]

Sorry about typo: TOX = TOS
Gary

On Mar 5, 2004, at 2:43 AM, Gary Tate wrote:

> 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
>>>>
>>>> _______________________________________________
>>>> juniper-nsp mailing list juniper-nsp at puck.nether.net
>>>> http://puck.nether.net/mailman/listinfo/junipe> r-nsp
>>>>
>>>
>>>
>>
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>