"Can someone clarify the queuing on a Juniper Router and and how it works on
the FPC. I have read the documentation on the queuing with regard to CoS
implementations which explains that each interface has 4 queues for queuing
the Packet Notification Headers. I spoke briefly to some Juniper personnel
who explained that their is a generic Precedence Map for the whole FPC.
They explained that their are 4 queues per FPC and that all interfaces share
the queues ! So its as if you have 4 large queues that are carved up and
spilt between the interfaces, kind of hard to explain. However no official
documentation could be released to support this. Anybody clarify exactly
what the situation on this ??"
Let me see if I can answer your question.
1. There can be up to 4 queues _per_port_ on all interfaces except the FE-48
PIC (only 1 queue per port).
2. By default IP precedence values 000-101 are queued in Q0 and IP
precedence values 110-111 (network control traffic) are queued in Q3.
3. By default only Q0 and Q3 are used.
4. Of the SDRAM on each FPC approximately 80 is allocated for packet
buffering with the remaining 20% for queuing packet notification cells.
5. By default the decision for the destination queue is done on the input
FPC.
6. You can configure CoS but it is applied to an FPC, therefore effecting
each interface (if enabled on the interface) on that FPC.
7. You can change the queue destination decision process with any of the 3
possibilities: 1. incoming interface, 2. ip precedence bits, 3. destination
ip address.
I'm not sure what problems you had but everything I've explained is in the
docs:
http://www.juniper.net/techpubs/software/junos50/swconfig50-interfaces/html/cos-overview.html
Message Posted at:
http://www.groupstudy.com/form/read.php?f=9&i=543&t=527
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