Brocade BigIron RX Series Configuration Guide - Manual (Page 607)

BigIron RX Series Configuration Guide 529
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Multi-Chassis Trunking overview
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Rate limiting multicast traffic in MCT VLANs
To configure the multicast rate limit at the NP level, enter a command such as the following.
BigIron RX(config)# multicast rate-limit 1000000 1 np 2/2
Syntax: [no] multicast rate-limit <avg-rate> <max-burst> np [slot/port | all]
To configure the multicast rate limit at the port level, enter a command such as the following .
BigIron RX(config)# multicast port-rate-limit 6 1 2/2
Syntax: [no] multicast port-rate-limit <average packet size> <% of traffic> <interface>
For variable descriptions, refer to “Rate limiting broadcast traffic in MCT VLANs” on page 528.
Rate limiting unknown-unicast traffic in MCT VLANs
To configure the unknown-unicast rate limit at the NP level, enter a command such as the following.
BigIron RX(config)# unknown-unicast port-rate-limit 6 1 2/2
Syntax: [no] unknown-unicast port-rate-limit <average packet size> <% of traffic> <interface>
For variable descriptions, refer to “ “Rate limiting broadcast traffic in MCT VLANs” on page 528.
NOTE
Due to hardware limitation, you cannot rate limit the unknown-unicast traffic at the port level.
Support for Layer 2 protocols in MCT
When running MCT, there are a number of requirements for the Layer 2 protocols: Metro Ring
Protocol (MRP), Spanning Tree Protocol (STP), and Rapid Spanning Tree Protocol (RSTP).
MRP
When running MRP with MCT, the MCT must conform with the following considerations:
• An ICL interface cannot be configured as an MRP secondary interface and vice versa if the
device is the MRP master and also, the ICL cannot be set to BLOCKING state.
• MRP cannot be enabled on the MCT CCEP port.
STP and RSTP
When running STP and RSTP with MCT, the STP algorithm has been modified such that the ICL
never goes to BLOCKING state. The ICL guard mechanism ensures that if the ICL is set to
BLOCKING state, then the port on which the superior Bridge Protocol Data Units (BPDUs) are being
received is moved to BLOCKING state and the ICL guard timer starts running on the interface. As
long as the timer runs, the superior BPDUs are received and dropped. The modified STP algorithm
ensures that the CCEP STP state information between the MCT peers is synchronized using
messages that are sent over CCP and that the CCEP interface state on both the MCT peers is the
same.
Only one of the MCT peers can send BPDUs to the MCT client. The designated bridge on the ICL
decides the MCT peer that must send the BPDUs to the client. The following are the new STP
states: