Example: Shared Pool Of Additional Bandwidth With Select Flows Rate-Limiting Hierarchical Policy; Figure 4: Shared Pool Of Additional Bandwidth With Select Flows - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - POLICY MANAGEMENT CONFIGURATION GUIDE 2010-10-04 Configuration Manual

Example: Shared Pool of Additional Bandwidth with Select Flows Rate-Limiting Hierarchical
Policy
Copyright © 2010, Juniper Networks, Inc.
Figure 4 on page 65 shows three classified flows, A, B, and C, each of which has an
individual rate limit with a peak rate of 1 Mbps. If flow A is exceeding its peak rate, rather
than drop the packet, the flow tries to use any bandwidth left in a shared rate limit
(extrabw) of peak rate of 2 Mbps. The packet is dropped only if both the individual and
the shared rate limit have no bandwidth left.
The total flow is limited to 5 Mbps, which is the sum of all the individual peak rates plus
the peak rate of the shared rate limit. Individual flows A, B, and C are limited to a maximum
of 3 Mbps (1 Mbps from its individual rate limit and up to 2 Mbps if it can consume the
entire shared pool); however, it cannot go below a 1 Mbps rate because of the other flows.
A shared rate limit enables many flows to share the extra bandwidth dynamically.

Figure 4: Shared Pool of Additional Bandwidth with Select Flows

This example uses transmit final so that those packets do not pass through the common
rate limit. Transmit final also indicates that there is no shared maximum. If the packets
are committed or conformed, they do not need to borrow extra bandwidth or subtract
tokens from it. The example uses exceeded action transmit conditional so that packets
above the individual rate-limit maximum are not dropped but sent to the next rate limit
in the hierarchy. Because this is transmit conditional, ownership of the packet also
transfers so the common rate limit can drop these packets if it has no bandwidth left.
host1(config)#rate-limit-profile indiv two-rate hierarchical
host1(config-rate-limit-profile)#committed-action transmit final
Chapter 5: Creating Rate-Limit Profiles
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