iLab Static routing Minoo Rouhi rouhi@net.in.tum.de Slides by Benjamin Hof hof@in.tum.de Chair of Network Architectures and Services Department of Informatics Technical University of Munich Lab 2 – 17ws 1 / 21
Outline Meta Hierarchical addressing Routing decision Autoconfiguration 2 / 21
Outline Meta Hierarchical addressing Routing decision Autoconfiguration 3 / 21
Recordings ◮ check that you can log in ◮ slides are with the videos (media portal) ◮ slides one day before the lecture (e-learning system) 4 / 21
First lab Reminder: ◮ first deadline on Sunday ◮ free slots on all days but Tuesday and Wednesday Your answers: ◮ understandable ◮ precise ◮ (concise) ◮ details: exhaustively cover the question Use the feedback from the correction. 5 / 21
Outline Meta Hierarchical addressing Routing decision Autoconfiguration 6 / 21
Address hierarchy building 1 border router building 2 building 2 floor 1 floor 2 7 / 21
Forwarding ./ routing ◮ routers operate on network layer ◮ forwarding is the distribution of data packets ◮ routing is the selection of the best path ◮ data/forwarding plane: packet forwarding ◮ control plane: create routing table ◮ management plane: administration (SSH, . . . ) ◮ routing information base ◮ forwarding information base 8 / 21
Internet protocol addresses Example 2001:db8::1 11 × 0x00 0010 0000 0000 0001 0000 1101 1011 1000 . . . 0000 0001 20 01 0d b8 :: 01 9 / 21
Internet protocol addresses Example 2001:db8::1 11 × 0x00 0010 0000 0000 0001 0000 1101 1011 1000 . . . 0000 0001 20 01 0d b8 :: 01 Example set of addresses: 2001:db8::/40 11 × 0x00 0010 0000 0000 0001 0000 1101 1011 1000 0000 0000 . . . 20 01 0d b8 00 /40 9 / 21
Classless inter-domain routing (CIDR) Example 2001:db8::/40 ◮ most significant 40 bits identify network ◮ rest identifies hosts ◮ rest can be split up, e.g. use 3 /64 networks 10 / 21
Example: CIDR 2001:db8:0:1::/64 2001:db8::/40 2001:db8:0:2::/64 2001:db8:0:3::/64 11 / 21
Routing table (incomplete) port network 12 / 21
Routing table (incomplete) port network 1 2001:db8:0:1::/64 12 / 21
Routing table (incomplete) port network 1 2001:db8:0:1::/64 2 2001:db8:0:2::/64 12 / 21
Routing table (incomplete) port network 1 2001:db8:0:1::/64 2 2001:db8:0:2::/64 2 2001:db8:0:3::/64 12 / 21
Routing table (incomplete) port network 1 2001:db8:0:1::/64 2 2001:db8:0:2::/64 2 2001:db8:0:3::/64 3 – 12 / 21
Routing table (incomplete) port network 1 2001:db8:0:1::/64 2 2001:db8:0:2::/64 2 2001:db8:0:3::/64 3 – 4 otherwise 12 / 21
Outline Meta Hierarchical addressing Routing decision Autoconfiguration 13 / 21
Longest prefix matching ◮ check for identity up to prefix length ◮ check if longer prefix also matches ◮ longest common prefix wins Example 1 198.51.100.0/24 2 198.51.100.0/26 What happens with: 1. 198.51.100.10 2. 198.51.100.70 3. 203.0.113.2 14 / 21
Forwarding information base 1 default dev eth0 via 192.0.2.1 2 192.0.2.0/30 dev eth0 3 198.51.100.0/24 dev eth1 via 198.51.100.130 4 203.0.113.0/24 dev eth1 via 198.51.100.130 5 198.51.100.128/30 dev eth1 6 203.0.113.240/28 dev eth2 15 / 21
Neighbour discovery and routing ǫ D α A δ β γ B θ C 1. What is our address? 2. What is the next hop? 3. What MAC address does the router have? 16 / 21
Outline Meta Hierarchical addressing Routing decision Autoconfiguration 17 / 21
Address types ◮ unspecified: ::/128 ◮ loopback: ::1/128 ◮ multicast: ff00::/8 ◮ link local: fe80::/10 ◮ global: almost all the rest 18 / 21
Stateless address autoconfiguration in IPv6 dst: solicited-node dst: all-routers router node ff02::1:ff00:0/104 ff02::2 link-local IP NS: DAD RS RA: prefix info global IP NS: DAD 19 / 21
SLAAC recap 1. link local address: fe80:: + modified EUI64 derived from MAC; other methods possible 2. duplicate address detection with neighbour solicitation to solicited-nodes 3. router solicitation to all-routers 4. router advertisement ◮ managed address ◮ other configuration ◮ prefix information ◮ lifetime ◮ autonomous flag ◮ prefix 5. generate global IP 6. DAD Requires /64. 20 / 21
What is still missing for us to be able to use the network conveniently? 21 / 21
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