Configuring Rate Limiting
December 2005
© Foundry Networks, Inc.
14 - 3
•
Rate limiting is available only on inbound ports on FastIron devices.
•
Fixed rate limiting is not supported on 10-Gigabit Ethernet ports.
Configuring a Port-Based Rate Limiting Policy
To configure rate limiting on a port, enter commands such as the following:
FESX424 Router(config)# interface ethernet 24
FESX424 Router(config-if-e1000-24)# rate input fixed 500000
These commands configure a fixed rate limiting policy that allows port 24 to receive a maximum of 500000 bits per
second (62500 bytes per second). If the port receives additional bytes during a given one-second interval, the
port drops all inbound packets on the port until the next one-second interval starts.
Syntax:
[no] rate-limit input fixed <average-rate>
The <average-rate> parameter specifies the maximum number of bits per second (bps) the port can receive. The
minimum rate that can be configured on FESX, FSX, and FWSX devices is 64,000 bps.
Configuring an ACL-Based Rate Limiting Policy
Software releases 02.3.03 and later provide support for IP ACL-based rate limiting of inbound traffic. ACL-based
rate limiting provides the facility to limit the rate for IP traffic that matches the permit conditions in extended IP
ACLs. This feature is available in the Layer 2 and Layer 3 code.
To configure ACL-based rate limiting on an X-Series device, you create individual
traffic policies
, then reference
the traffic policies in one or more ACL entries (also called clauses or statements). The traffic policies become
effective on ports to which the ACLs are bound.
Configuration procedures for ACL-based rate limiting are in the chapter “Traffic Policies” on page 15-1.
Optimizing Rate Limiting
By default, rate limiting is optimized for packets that are 256 bytes in size. This packet size includes 14 bytes of
Layer 2 header (Ethernet II untagged) and 4 bytes of Layer 2 CRC.
To optimize rate limiting for all packet sizes, use the
payload-only
parameter. When this parameter is specified,
the system excludes Layer 2 header and Layer 2 checksum (CRC) from the calculations, and the rate is accurate
for all packet sizes and Layer 2 overhead (Layer 2 CRC). Layer 2 overhead for different encapsulations
is as follows:
•
Untagged Ethernet-II – 18 bytes
•
Tagged Ethernet-II – 22 bytes
•
LLC over Untagged Ethernet-II – 21 bytes
•
LLC over Tagged Ethernet-II – 25 bytes
•
LLC/SNAP over Untagged Ethernet-II – 26 bytes
•
LLC/SNAP over Tagged Ethernet-II – 30 bytes
To optimize rate limiting, enter commands such as the following:
FESX424 Router(config)# interface ethernet 24
FESX424 Router(config-if-e1000-24)# rate input fixed 500000 payload-only
These commands configure a fixed rate limiting policy that allows port 24 to receive a maximum of 500000 bits per
second. The payload-only parameter causes the device to exclude the Layer 2 header and Layer 2 checksum
from the calculations.
Содержание FastIron Edge Switch X424
Страница 36: ...Foundry Configuration Guide for the FESX FSX and FWSX 2 12 Foundry Networks Inc December 2005...
Страница 56: ...Foundry Configuration Guide for the FESX FSX and FWSX 3 20 Foundry Networks Inc December 2005...
Страница 70: ...Foundry Configuration Guide for the FESX FSX and FWSX 4 14 Foundry Networks Inc December 2005...
Страница 198: ...Foundry Configuration Guide for the FESX FSX and FWSX 8 38 Foundry Networks Inc December 2005...
Страница 316: ...Foundry Configuration Guide for the FESX FSX and FWSX 12 26 Foundry Networks Inc December 2005...
Страница 334: ...Foundry Configuration Guide for the FESX FSX and FWSX 13 18 Foundry Networks Inc December 22 2005...
Страница 350: ...Foundry Configuration Guide for the FESX FSX and FWSX 15 12 Foundry Networks Inc December 2005...
Страница 458: ...Foundry Configuration Guide for the FESX FSX and FWSX 18 18 Foundry Networks Inc December 2005...
Страница 712: ...Foundry Configuration Guide for the FESX FSX and FWSX 22 32 Foundry Networks Inc December 2005...
Страница 760: ...Foundry Configuration Guide for the FESX FSX and FWSX A 34 Foundry Networks Inc December 2005...
Страница 796: ...Foundry Configuration Guide for the FESX FSX and FWSX C 18 Foundry Networks Inc December 2005...
Страница 820: ...Foundry Configuration Guide for the FESX FSX and FWSX E 10 Foundry Networks Inc December 2005...