ZXR10 5900/5200 Series User Manual (Basic Configuration Volume)
that multiple packets compete with each other for resources at the
same time.
ZXR10 5900/5200 supports Strict Priority (SP) and Weighted
Round Robin (WRR) queue scheduling modes.
Eight output
queues of a port can adopt different modes respectively.
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SP Scheduling
SP is to strictly schedule data of each queue according to queue
priority. First send packets in the highest priority queue and
after that, send packets in the higher priority queue. Similarly,
after that, send packets in the lower priority queue, and so on.
SP scheduling makes packets of key services processed prefer-
entially, thus guaranteeing service quality of key services. But
the low priority queue may never be processed and "starved”.
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WRR
WRR makes each queue investigated possibly and not
“starved”. Each queue is investigated at different time, that is,
has different weight indicating the ratio of resources obtained
by each queue. Packets in the high priority queue have more
opportunities to be scheduled than the low priority queue.
Data priority is contained in the 802.1P label. If data entering the
port is not marked with an 802.1P label, a default 802.1p value
will be assigned by the switch.
Redirection and Policy Routing
Redirecting is used to make the decision again about the forward-
ing of packets with certain features according to traffic classifica-
tion. Redirection changes transmission direction of packets and
export messages to the specific port, CPU or next-hop IP address.
Redirect packets to the next-hop IP address to implement policy
routing.
On the aspect of packet forwarding control, policy-based route has
more powerful control capacity than traditional route because it
can select a forwarding path according to the matched field in the
ACL. Policy routing can implement traffic engineering to a certain
extent, thus making traffic of different service quality or different
service data (such as voice and FTP) to go to different paths. The
user has higher and higher requirements for network performance,
therefore it is necessary to select different packet forwarding paths
based on the differences of services or user categories.
Priority Marking
Priority marking is used to reassign a set of service parameters
to specific traffic described in the ACL to perform the following
operations:
1. Change the CoS queue of the packet and change the 802.1p
value.
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