IPv6 ICMP Feature Configuration
As with the Internet Control Message Protocol (ICMP) for IPv4, ICMP for IPv6 provides error and informational messages. Implementation of the stateless auto configuration, neighbor discovery, and path MTU discovery features use ICMP messages.
This section explains how to configure following IPv6 ICMP features:
ICMP Rate Limiting
You can limit the rate at which IPv6 ICMP error messages are sent out on a network. IPv6 ICMP implements a token bucket algorithm.
To illustrate how this algorithm works, imagine a virtual bucket that contains a number of tokens. Each token represents the ability to send one ICMP error message. Tokens are placed in the bucket at a specified interval until the maximum number of tokens allowed in the bucket is reached. For each error message that ICMP sends, a token is removed from the bucket. If ICMP generates a series of error messages, messages can be sent until the bucket is empty. If the bucket is empty of tokens, error messages cannot be sent until a new token is placed in the bucket.
You can adjust the following elements related to the token bucket algorithm:
ICMP Redirects
You can enable a Layer 3 switch to send an IPv6 ICMP redirect message to a neighboring host to inform it of a better first-hop router on a path to a destination. By default, the sending of IPv6 ICMP redirect messages by a Layer 3 switch is disabled. (For more information about how ICMP redirect messages are implemented for IPv6, refer to IPv6 Neighbor Discovery Configuration.)