© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv6 Operations Describing IPv6 ICMP Types

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Neighbor Discovery: Redirect Redirect is used by a router to signal the rerouting of a packet to a better router. Redirect: Src = R2 Dst = A Data = good router = R1 2001:DB8:C18:2::/64 R1 R2 Src = A Dst IP = 2001:DB8:C18:2::1 Dst Ethernet = R2 (default router) BA

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v ICMP Errors Type 1: Destination Unreachable Code 0: No route to destination Code 1: Communication administratively prohibited Code 2: Not assigned Code 3: Address unreachable Code 4: Port unreachable Code 5: Source address failed ingress/egress policy Code 6: Reject route to destination

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v ICMP Errors (Cont.) Type 2: Packet Too Big Code 0: Message contains MTU of the next hop

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v ICMP Errors (Cont.) Type 3: Time Exceeded Code 0: Hop limit exceeded Code 1: Fragment reassembly time exceeded

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v ICMP Errors (Cont.) Type 4: Parameter Problem Code 0: Erroneous header field Code 1: Unrecognized next header type Code 2: Unrecognized IPv6 option Pointer identifies the octet offset within the invoking packet where the error was detected.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v ICMP: Test Type 128: Echo Request Type 129: Echo Reply

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v ICMP: Multicast Listener Discovery Type 130: Multicast Listener Query Type 131: MLDv1 Multicast Listener Report Type 132: MLDv1 Multicast Listener Done Type 143: MLDv2 Multicast Listener Report

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Summary ICMPv6 is used for control messages in IPv6 and is split into two major types: informational messages such as echo-request and error messages such as packet too big. ICMPv6 is an integral part of the IPv6 protocol and is required for the network to function properly. The ICMPv6 redirect message is used by a router to inform a host of a better first-hop router to deliver packets to a specific destination. If a router recognizes a better path for a host to use for a destination, it will send an ICMPv6 redirect message to that host, providing the address of the better router. Multicast signaling between a host and the designated router for that subnet is provided by another ICMPv6 message setthe MLD messages. These messages allow the host to inform the designated router that it is interested in obtaining a given stream or has completed listening to a multicast stream.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v