iLab 2 Internet Protocol version 6 Stefan Liebald - - PowerPoint PPT Presentation

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iLab 2 Internet Protocol version 6 Stefan Liebald liebald@net.in.tum.de Lehrstuhl fr Netzarchitekturen und Netzdienste Fakultt fr Informatik Technische Universitt Mnchen April 25, 2017 Based on slides of Lukas Schwaighofer 1

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iLab 2

Internet Protocol version 6 Stefan Liebald liebald@net.in.tum.de

Lehrstuhl für Netzarchitekturen und Netzdienste Fakultät für Informatik Technische Universität München

April 25, 2017

Based on slides of Lukas Schwaighofer

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Address exhaustion

Figure: IPv6 exhaustion (source: https://xkcd.com/865)

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IPv4 and IPv6 Header

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IPv6 Differences

◮ 128 bit addresses compared to 32 bit in IPv4 ◮ Fragmentation only on endhosts ◮ Header:

◮ Fixed header length (40 byte) + extension headers ◮ Fewer fields (no checksum, fragmentation)

◮ Integrated IPsec via extension header ◮ No more broadcast → multicast ◮ NDP instead of ARP 4

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IPv6 Address notation

◮ 8 blocks of 2 bytes, colon seperated: ◮ e.g.: 2001:0db8:0000:0000:0000:0102:0000:0304 ◮ can be shortened:

◮ replace longest block of zeros with :: ◮ ommit leading zeros ◮ e.g. 2001:db8::102:0:304

◮ What about ports?

◮ use [IPv6-address]:port ◮ e.g.: [2001:db8::102:0:304]:80

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IPv6: Important well defined address types

Address (subnet) Type ::1/128 Loopback fe80::/10 Link-local unicast fc00::/7 Unique Local unicast ff00::/8 Multicast

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IPv6: Important multicast addresses

Address Definition ff02::1 All nodes on local network segment ff02::2 All routers on local network segment ff02::1:2 All DHCPv6 servers on local network segment ff02::1:ff00:0/104 Solicited-node multicast prefix

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Neighbor Discovery Protocol (NDP)

◮ Resolves MAC address of given IPv6 address to send packet

ver ethernet:

◮ Sender sends Neighbour Solicitation to target: ◮ IP dest: Solicitated Node Multicast IPv6 Address of target

(prefix + last 3 octets of address)

◮ MAC dest: IPv6 multicast over ethernet address (33:33:+last 4

ctets of v6 multicast address)

◮ Full IPv6 address of target as payload ◮ Target returns Neighbour Advertisment with MAC as payload

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Outlook Stateless Address Auto Configuration

1. Generate Link Local (LL) address
2. Perform Duplicate Address Detection (DAD)

◮ Send Neighbour Solicitation to own LL address ◮ no response → assign address

3. Send Router Solicitation (RS) to all routers
4. Take information (prefix) from response (Router Advertisment

(RA)) and configure global IP address

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ICMPv6

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