Administrator Guide
Feature and Functionality Dell Networking OS Release
Introduction
Documentation and Chapter Location
MXL
IPv6 QoS
trust DSCP values N/A IPv6 Multicast in this chapter
ICMPv6
ICMPv6 is supported on the MXL switch platform.
ICMP for IPv6 combines the roles of ICMP, IGMP and ARP in IPv4. Similar to IPv4, it provides functions for reporting delivery and
forwarding errors, and provides a simple echo service for troubleshooting. The Dell Networking OS implementation of ICMPv6 is
based on RFC 4443.
Generally, ICMPv6 uses two message types:
• Error reporting messages indicate when the forwarding or delivery of the packet failed at the destination or intermediate node.
These messages include Destination Unreachable, Packet Too Big, Time Exceeded and Parameter Problem messages.
• Informational messages provide diagnostic functions and additional host functions, such as Neighbor Discovery and Multicast
Listener Discovery. These messages also include Echo Request and Echo Reply messages.
The ping and traceroute commands extend to support IPv6 addresses. These commands use ICMPv6 Type-2 messages.
Path MTU Discovery
IPv6 path maximum transmission unit (MTU) discovery is supported on the MXL switch platform.
Path MTU, in accordance with RFC 1981, denes the largest packet size that can traverse a transmission path without suering
fragmentation. Path MTU for IPv6 uses ICMPv6 Type-2 messages to discover the largest MTU along the path from source to
destination and avoid the need to fragment the packet.
The recommended MTU for IPv6 is 1280. Greater MTU settings increase processing eciency because each packet carries more
data while protocol overheads (for example, headers) or underlying per-packet delays remain xed.
Figure 55. Path MTU Discovery Process
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IPv6 Addressing