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12 votes
Accepted

How does router advertisement in IPv6 avoid IP conflict?

A host performs Duplicate Address Detection (DAD) before actually activating the given address on the interface RFC 2462 has to say about this: 5.4. Duplicate Address Detection Duplicate Address ...
Marc 'netztier' Luethi's user avatar
7 votes

OSI layer of Neighbor Discovery Protocol

The OSI model is a conceptual idea -- it doesn't relate to anything that people actually built. Moreover, IPv4 and IPv6 were developed without the OSI model in mind, so there is no direct correlation ...
Ron Trunk's user avatar
  • 67.6k
7 votes
Accepted

OSI layer of Neighbor Discovery Protocol

First of all: In every "model" you will find some aspects that do not describe the reality correctly. This is true for "models" in computer science, financial theory, politics or ...
Martin Rosenau's user avatar
5 votes
Accepted

Network flooded with ICMPv6 Multicast Listener Report Packets

You wouldn't be looking for ARP entries with IPv6, since ARP doesn't exist with IPv6. You would be looking for IPv6 ICMP Neighbor Discovery cache. IPv6 MLD messages are used similarly to IPv4's IGMP ...
HostBits's user avatar
  • 636
4 votes

OSI layer of Neighbor Discovery Protocol

I also want to answer my own question. The answer concerns particularly the two UPDATES which I appended to the initial question. I wondered what will happen if I try to send any NDP ICMPv6 message to ...
JenyaKh's user avatar
  • 245
3 votes

How to handle IPv6 Extension Header Options with action = 01

When the higher order bits are 01, it is supposed to discard the packet and, regardless of whether or not the packet's Destination Address was a multicast address, send an ICMP Parameter Problem, Code ...
Ron Maupin's user avatar
  • 99.8k
3 votes

OSI layer of Neighbor Discovery Protocol

NDP belongs to the L3 network layer. It is an essential part of IPv6, just like ICMPv6 which it a special form or extension of.
Zac67's user avatar
  • 84.8k
2 votes
Accepted

How is ICMP Packet Too Big handled in IPv6?

With IPv6, routers don't fragment packets. End nodes might. Path MTU discovery (PMTUD) is mandatory for IPv6, so the all path nodes and the end nodes agree on the path MTU before actual data begins to ...
Zac67's user avatar
  • 84.8k
2 votes
Accepted

Global Unicast in IPv6 Neighbor Discovery

But everything that I've heard of Neighbor Discovery told me that IPv6 addresses for which MAC addresses are searched should be Link Local Unicast (starting with FE80::/10) rather than Global ...
Ron Maupin's user avatar
  • 99.8k
2 votes
Accepted

How can IPv6 host know default router's IPv6 address using RA?

The RA IPv6 packet will have the router address as the source IPv6 address. A host doesn't really need to know the router's IP address to send packets to other hosts. On a LAN, frames are sent to a ...
Ron Maupin's user avatar
  • 99.8k
2 votes
Accepted

Enabling Multicast Listener Discovery (MLD)

First, NICs have no idea if they are used for IPv4, IPv6, IPX, or any other layer-3 protocol. Ethernet, and other IEEE LAN protocols, support multicast, which is heavily used in IPv6. MLD is ...
Ron Maupin's user avatar
  • 99.8k
2 votes

How to handle ICMP-in-IPv6 or ICMPv6-in-IPv4?

RFC 8200 states that the "next header" field in IPv6 uses the same values as the "protocol" field in IPv4. However, RFC 4443 states: Every ICMPv6 message is preceded by an IPv6 header ... The ...
Martin Rosenau's user avatar
2 votes
Accepted

Why is ICMP placed in transport layer in 6TSCH protocol stack?

ICMP is an integral part of IP's network layer. The linked RFC shows that it is technically encapsulated by IP like a transport-layer protocol (which is correct) but doesn't state that ICMP belongs to ...
Zac67's user avatar
  • 84.8k
2 votes
Accepted

Actually ICMP message makes layer3 reliable?

But when packets gets dropped in between route then respective router informs the source that packets gets dropped due to greater PTUMD(in ipv6) then source will fragment the packet for delivery. ...
Zac67's user avatar
  • 84.8k
2 votes
Accepted

Is an ICMPv6 neighbor advertisement meaningful if no options are set?

In that packet, the [S]olicited flag indicates that the advertisement is a response to a solicitiation message. The L2 MAC address isn't included since it hasn't changed (that would trigger the [O]...
Zac67's user avatar
  • 84.8k
1 vote

Calculating Checksum for ICMPv6 Packet

Using the UDP checksum is optional for IPv4 (required for IPv6). If the checksum is not used, the checksum is set to all-zeroes. If the checksum is used, and the computed checksum is all-zeroes, the ...
Ron Maupin's user avatar
  • 99.8k
1 vote

How to handle ICMP-in-IPv6 or ICMPv6-in-IPv4?

ICMPv4 is encapsulated in an IPv4 packet, and ICMPv6 in IPv6. There is no way an IPv4-only host would receive and parse an IPv6 packet (and vice versa).
Zac67's user avatar
  • 84.8k
1 vote

OSI layer of Neighbor Discovery Protocol

NDP belongs to the OSI layer 3 (Network layer) and TCP/IP layer 2 (Internet layer), why? NDP is routable Since NDP runs on ICMPv6, and ICMPv6 is routable since it runs on IPv6, NDP can be routed ...
Anim Mouse's user avatar

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