Operating Notes For Rate-Limiting - HP ProCurve 6400cl Series Management And Configuration Manual

Port Traffic Controls
Rate-Limiting
13-6
Figure 13-2. Example of Rate-Limit Settings Listed in the "show config" Output

Operating Notes for Rate-Limiting

Rate-Limiting is available on all types of ports on the switches covered by
■
this guide, and at all port speeds configurable for these devices. (Rate-
Limiting is not allowed on trunked ports.)
■ The configured rate limit on a port reflects the permitted forwarding rate
from the port to the switching fabric, and is visible as the average rate of
the outbound traffic originating from the rate-limited port. Also, rate-
limiting reflects the available percentage of a port's entire inbound band-
width. The rate of inbound flow for traffic of a given priority and the rate
of flow from a rate-limited port to a particular queue of an outbound port
are not measures of the actual rate limit enforced on a port.
Rate-Limiting operates on a per-port basis, regardless of traffic priority.
■
Configuring rate-limiting on a port where other features affect inbound
port queue behavior (such as flow control) can result in the port not
achieving its configured rate-limiting maximum. For example, in some
situations with flow control configured on a rate-limited port, there can
be enough "back pressure" to hold high-priority inbound traffic from the
upstream device or application to a rate that is lower than the configured
The outbound port priority
queues 1 - 4 for ports A1-A2 are
configured with the indicated
Guaranteed Minimum
Bandwidth percentages.
Ports A3-A5 are configured with a
rate limit of 60 %. (Ports A1 and A2 are
not configured for rate-limiting.)