Combining queuing disciplines, Handle semantics, Cops: common open policy service – Znyx Networks bh5700 User Manual

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tc filter add dev zhp0 protocol arp parent 100:0 u32 match u32 2

0xffff at +4 flowid 100:30

Combining Queuing Disciplines

Any of the queue length limiting disciplines can be used with the bandwidth management queue
disciplines, by defining them with the handle of one of the classes as their parent. For the htb
queueing discipline, each class has an explicit handle specified when it is defined. For the prio
queueing discipline, including wrr, each band is a class; their handles are formed from the
handle of the prio qdisc by appending a minor number of 1 to n for the n bands. For example, the
following commands define two strict priority queues for port zre5, with the lower priority
queue limited to 32 kb and the higher priority queue limited to 32 kb:

tc qdisc add dev zre5 root handle 100:0 prio bands 2 priomap 0 0 0 0
1 1 1 1

tc qdisc add dev zre5 parent 100:1 handle 110:0 bfifo limit 32kb

tc qdisc add dev zre5 parent 100:2 handle 120:0 bfifo limit 32kb

These translation rules handle conversions of individual rules from tc entries into hardware
entries. They do not explain the results of creating rules that are individually supported; but
which do not make sense in conjunction.

Although the translation rules handle some inconsistency between software and hardware, a user
must define a combination of rules that is reasonable in hardware, to ensure predictable results.

Handle Semantics

All examples have illustrated zqosd copying tc rules into hardware. In fact, the zqosd utility
also enables the user to add tc rules that remain only in software. This selection is based on
handles. zqosd processes all supported queue disciplines and filters with handles between 100:0
and 200:FFFF.

COPS: Common Open Policy Service

The Common Open Policy Service (COPS) is a protocol for distributing networking policy to
devices such as switches and routers. COPS allows a single Policy Decision Point (PDP) to
distribute policy to multiple Policy Enforcement Points (PEPs). A PDP acts as a server for PEP
clients. Figure 7.6 provides an illustration of the COPS Network Architecture.

Ethernet Switch Blade User's Guide

release 3.2.2j

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