Talk:Neighbor Discovery Protocol

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DNS server specification?[edit]

The DHCPv6 entry says that network clients can also find available DNS servers with NDP, but no such method is detailed in this article.--99.232.75.232 (talk) 15:28, 30 September 2010 (UTC)[reply]

It's a fairly new method, but still experimental. Added mention. Kbrose (talk) 17:59, 30 September 2010 (UTC)[reply]

"Network layer"?[edit]

The article currently reads "It operates at the Network Layer of the Internet model (RFC 1122)" which doesn't make sense because it points at an OSI layer. There is no such thing as a "network layer" in the internet model. So what layer does it operate at? 66.114.147.82 (talk) 18:43, 4 February 2011 (UTC)[reply]

The first paragraph now states that NDP operates at the Internet Layer, yet the Internet protocols box at the right shows it in the Link layer.206.47.231.164 (talk) 14:21, 3 October 2012 (UTC)[reply]

And both, of course are total nonsense, since NDP would have a hard time traversing routers. It operates in the Link Layer. That's where address assignment, link discovery, etc., happen. Kbrose (talk) 02:48, 4 January 2013 (UTC)[reply]

First internet layer should be called Network Layer as that is what OSI calls that layer. your network layer may not be INTERNET protocol.

As I understand IPv6 NDP is a group of ICMPv6 messages and there for operates at the Network Layer as was formally stated in the first paragraph. The table on the right is also wrong indicating NDP as link layer. ARP the equivalent in IPv4 is link layer and was a hack because IPv4 cant send IP messages without knowing the mac address destination so ARP had to be a link layer protocol. IPv6 autoconfigures local-link IPv6 addresses and uses this to send the ICMPv6 messages (which are Network layer packets) that does the same function as used to be done by ARP. Unlike ARP which is link layer ICMP is network layer and so NDP is Network layer. The article is now more wrong as it now does not say at all that this is internet layer protocol <http://packetlife.net/blog/2008/aug/28/ipv6-neighbor-discovery/> Which includes a link to a wireshark trace of ICMPv6 used for NDP and this <http://wiki.wireshark.org/SampleCaptures?action=AttachFile&do=get&target=arp-storm.pcap> is a link to a wire shark trace of ARP for comparison. ARP IS link layer ICMP and NDP are NOT. PS you will need to install wireshark to view these Network trace files easily. — Preceding unsigned comment added by 119.225.152.24 (talk) 00:21, 7 May 2013 (UTC)[reply]

The Internet Protocol Suite does not know a Network Layer, and IPv6 is not developed on the OSI model of networking. NDP, just like ARP, operates strictly on the local link, never traverses routers and therefore is a Link Layer protocol, whether it uses IP has no bearing. TCP/IP does not restrict itself to hierarchical layering encapsulation. Kbrose (talk) 01:38, 8 May 2013 (UTC)[reply]

I respectfully disagree NDP is ICMP packets and as such are embedded in the IPv6 frame on the network I know it preforms the function of link layer setup but it is still carried IN the Internet layer IPv6 frame. — Preceding unsigned comment added by 119.225.152.24 (talk) 03:45, 16 May 2013 (UTC) I also not that the http://www.ietf.org/rfc/rfc2461.txt places NDP in the "ICMP layer" in bottom of section 3.1. The traces I provided in my last change also shows NDP clearly in the ICMP layer 3 level. I know that NDP is used to find the layer 2 addresses but it is carried in the layer 3 frame and defined as a part of IPv6 ICMP messages/ protocol. The fact that it does not normally limited to the local link causes confusion but does not change the fact that it is layer3. Another source of confusion is the term Link Loacl address which is a layer 3 address for the local link. Also this Microsoft page http://technet.microsoft.com/en-us/library/cc781672(v=ws.10).aspx graphic shows ND in the layer3 level of the diagram. Please review.[reply]

You insist on using networking terms that are inappropriate in this context. The Internet Protocol Suite does not number its layers, layer 3 simply does not exist in this model. If you want to rewrite articles and the protocols of the Internet based on OSI then you have to find a good justification for that. The IETF doesn't practice it. TCP/IP does not use strict layering, not hierarchical encapsulation, and what kind of addressing NDP uses is of no concern. TCP/IP classifies its layers by scope of operation, as the articles on the model on WP reflect properly. The term ICMP layer, as you quoted, does not imply any kind of larger networking scheme at work. Even your cited MS page does not in fact place ND into any TCP/IP layer, it shows it as part of IPv6, and only shows rough correspondence between OSI, TCP/IP, and IPv6 networking. If you observe closely, the IPv6 'layer' spans outside of the Internet Layer above and below. In addition, the article explicitly states that Neighbor Discovery is a series of five ICMPv6 messages that manage node-to-node communication on a link. Again, it says on a link. Kbrose (talk) 15:52, 16 May 2013 (UTC)[reply]

Kbrose you are wrong about addressing and encapsulation. Those are the two central issues in this debate. Hierarchical encapsulation is an unambiguous way to determine where a protocol belongs in the scheme of things. Can you justify your "scope of operation" argument? MikeMatera (talk) 23:30, 3 March 2015 (UTC)[reply]

Sorry you feel that way, but I didn't invent the Internet Protocol Suite. The IETF doesn't care about strict layering either and has discarded hierarchical encapsulation since inception of TCP/IP. The principle of scope comes from the first definitions of the Internet Protocol Suite. Kbrose (talk) 22:17, 4 March 2015 (UTC)[reply]

You keep making claims about what the IETF thinks or cares about but where is your evidence? A better characterization of my feelings would be curiosity. How can you justify the claim that the IETF doesn't care about strict layering? What does discarding hierarchical encapsulation mean? This article is misleading. It misunderstands a key component of IPv6 because of the way IPv4 worked. MikeMatera (talk) 08:21, 6 March 2015 (UTC)[reply]

So IGMP and MLD also are also Link Layer protocols? And so is PIM, given it has to have a TTL of 1 which will give PIM packets a hard time traversing a router as well. Tommiie (talk) 08:59, 1 July 2017 (UTC)[reply]

Another Reference[edit]

I've been going mad trying to nail down how ND works and especially how it relates to link-local addressing. It's pretty complicated and to make matters worse, most tutorials and docs focus more on setting up tunneling and auto-configuration on the LAN side.

I finally found this document, which is a bit dated, but starting around page 52 has a good intro to ND and link-local. If someone more expert in this area wants to edit this page, this might make for a good reference: http://www.renater.fr/IMG/pdf/BT-IPv6-Tutorial-110204-2.pdf Ddiggler2000 (talk) 05:24, 13 June 2011 (UTC)[reply]

External Reference[edit]

The external reference points to a page on the website fengnet.com (in Chinese). It appears that this website has content that violates copyright. Could this be verified ? — Preceding unsigned comment added by AbhinavModi (talk • contribs) 05:03, 21 December 2012 (UTC)[reply]