Brocade BigIron RX Series Configuration Guide - Manual (Page 606)

528 BigIron RX Series Configuration Guide
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Multi-Chassis Trunking overview
20
ICL traffic handling
An ICL link on the BigIron RX device can be a single port, a static LAG, or an LACP LAG. On the
BigIron RX device, only MCT VLANs are configured over the ICL. For MCT VLANs, MAC learning is
disabled on the ICL ports.
BUM traffic handling in MCT VLANs
On the BigIron RX device, broadcast, unknown-unicast and multicast (BUM) traffic processing in
MCT VLANs is handled by software due to hardware limitations. All the BUM traffic on the
cluster-enabled VLANs hits the LP CPU, and the scenario is similar to VLANs with CPU flooding,
which are enabled using VLAN commands such as no unknown-unicast-flooding and no
multicast-flooding. In this case, the egress forwarding rates for BUM traffic are similar to VLANs
with CPU flooding.
NOTE
Brocade recommends configuration of MCT ports on the same NP.
When MCT is enabled, you must explicitly configure the BUM rate limiting. Total amount of BUM
traffic for the network processor (NP) with MCT enabled ports needs to be limited to 3 Mbps. For
broadcast and multicast tarffic, the rate limiting can be configured either at NP or port level,
whereas for unknown-unicast traffic, the rate limiting can only be configured at NP level due to
hardware limitation.
Rate limiting broadcast traffic in MCT VLANs
To configure the broadcast rate limit at the NP level, enter a command such as the following .
BigIron RX(config)# broadcast rate-limit 1000000 1 np 3/2
Syntax: [no] broadcast rate-limit <avg-rate> <max-burst> np [slot/port | all]
The <avg-rate> variable specifies the maximum number of bits a port is allowed to receive during a
one-second interval in Kbps. Possible values are from 1 through 429467295. The default value is
4294967295
The <max-burst> variable specifies the total number of bits that can pass during a burst. Possible
values are from 1 through 429467295. The default value is 4294967295.
The np [slot/port] parameter allows you to rate limit a specific port on the NP.
The np all parameter allows you to rate limit all the ports on the NP.
To configure the broadcast rate limit at the port level, enter a command such as the following .
BigIron RX(config)# broadcast port-rate-limit 6 1 3/2
Syntax: [no] broadcast port-rate-limit <average packet size> <% of traffic > <interface>
The <average packet size> variable specifies the average packet size of the incoming traffic.
The <% of traffic> variable specifies the amount of incoming traffic to be rate limited in
percentage.
The <interface> variable specifies the interface to be rate limited. The rate limit is applied to all the
ports on the NP to which the specified interface belongs.