Icmp For Ipv6 - Cisco MDS 9000 series Configuration Manual

About IPv6
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
Figure 8-5
IPv6 unicast or anycast address
Solicited-node multicast address
FF02
There are no broadcast addresses in IPv6. IPv6 multicast addresses are used instead of broadcast
Note
addresses.

ICMP for IPv6

Internet Control Message Protocol (ICMP) in IPv6 functions the same as ICMP in IPv4—ICMP
generates error messages such as ICMP destination unreachable messages, and informational messages
such as ICMP echo request and reply messages. Additionally, ICMP packets in IPv6 are used in the IPv6
neighbor discovery process, path MTU discovery, and the Multicast Listener Discovery (MLD) protocol
for IPv6. MLD is based on version 2 of the Internet Group Management Protocol (IGMP) for IPv4.
A value of 58 in the Next Header field of the basic IPv6 packet header identifies an IPv6 ICMP packet.
ICMP packets in IPv6 resemble a transport-layer packet in the sense that the ICMP packet follows all
the extension headers and is the last piece of information in the IPv6 packet. Within IPv6 ICMP packets,
the ICMPv6 Type and ICMPv6 Code fields identify IPv6 ICMP packet specifics, such as the ICMP
message type. The value in the Checksum field is derived (computed by the sender and checked by the
receiver) from the fields in the IPv6 ICMP packet and the IPv6 pseudoheader. The ICMPv6 Data field
contains error or diagnostic information relevant to IP packet processing.
ICMP packet header format.
Figure 8-6
Next header = 58
ICMPv6 packet
ICMPv6 type
Cisco MDS 9000 Family NX-OS IP Services Configuration Guide
8-13
IPv6 Solicited-Node Multicast Address Format
Prefix
0
128 bits
IPv6 ICMP Packet Header Format
ICMPv6 code
ICMPv6 data
Chapter 8 Configuring IPv6 for Gigabit Ethernet Interfaces
Interface ID
24 bits
1 FF Lower 24
IPv6 basic header
ICMPv6 packet
Checksum
OL-19525-01,Cisco MDS NX-OS Release 4.2(1)
Figure 8-6 shows the IPv6