LSP, Hierarchy, broadcast routing, anycast routing .pptx

network layer : Routing protocols

1. Link state, broadcast, hierarchical, multicasting, any cast, congestion control algorithms

2. Distance vector routing algorithm

3. LSPs

4. LINK STATE ROUTING PROTOCOL Entire topology is available List of nodes Links Including the type, cost metric, Paths, links up or down City map

5. 4 Rules Link state routing – creation of LSPs Generation of the Link state packets (LSPs) Creation of links, state of the links Dissemination of LSPs to every other router Flooding Formation of shortest path tree for each node Calculation of routing table based on shortest path tree

6. LSP carries a lot of information Carries lot of information Node identity List of links Sequence number – flooding Age – distinguishes new LSPs from Old ones Assume - Minimum amount of data Node identity, list of links needed to make the topology Sequence number and age – flooding

7. When there is a change in the topology of the domain. Triggering of LSP dissemination is the main way of quickly informing any node in the domain to update its topology. On a periodic basis. The period in this case is much longer compared to distance vector routing As a matter of fact, there is no actual need for this type of LSP dissemination. It is done to ensure that old information is removed from the domain. The timer set for periodic dissemination is normally in the range of 60 min or 2h based on the implementation. A longer period ensures that flooding does not create too much traffic on the network.

8. LSP The creating node sends a copy of the LSP out of each interface. A node that receives an LSP compares it with the copy it may already have. If the newly arrived LSP is older than the one it has (found by checking the sequence number ), it discards the LSP. If it is newer, the node does the following: It discards the old LSP and keeps the new one. It sends a copy of it out of each interface except the one from which the packet arrived . This guarantees that flooding stops somewhere in the domain (where a node has only one interface).

9. Hierarchical routing Networks grow Router memory consumed Increasing routing tables More CPU time needed to scan More bandwidth is needed to send status report One stage reached where tables are full

10. Routers are divided into regions Each router will route its packet to the destination in its own region but not to other regions HUGE networks – two level hierarchy may be insufficient

11. Regions

12. Example 1 720 routers 24 regions 30 routers each 30 local entries and 23 entries for other regions 53 entries

13. Example 2 720 routers 8 clusters 9 regions 10 routers each 10 for local entries + 8 for other regions + 7 for other clusters Total 25 entries

14. Broadcast routing Weather report Stock market updates Live radio programs Broadcasting means sending all the destinations simultaneously 1. Flooding

15. Multi destination routing List of destinations or a bit map indicating desired destinations When router receives a packet check the destinations and the required number of output lines

16. Multi destination routing Packet Content:   A multidestination packet carries a list or a bit map of the intended destinations. Router Processing:   When a router receives such a packet, it checks the destination list. Packet Replication:   The router then creates a new copy of the packet for each necessary output line. Forwarding:   Each new copy is forwarded along its respective output line, containing only the destinations relevant to that specific path. Key Aspects

17. Efficiency:   By replicating packets only when necessary at certain points, multidestination routing minimizes redundant traffic on the network, thus saving bandwidth compared to sending separate packets to each destination.  Applications:   It's a fundamental mechanism for services that require one source to deliver information to many receivers, such as video conferencing, live streaming, and other forms of group communication.  Contrast with Unicast:   In contrast to unicast (one-to-one) routing, multidestination routing addresses one-to-many scenarios.  Relationship to Multicast and Broadcast  Multicast:   This is a type of one-to-many communication where packets are sent to a specified group of recipients. Broadcast:   This is a one-to-all communication, sending a packet to every device on the network. Multicast can be seen as a more refined form of broadcast

18. RVPF

19. Anycast

20. Distance vector routing and link state routing are intradomain routing protocol Inside autonomous systems not between DVR more LSR needs huge amount of resources to calculate routing table Heavy traffic bsc . of flooding Path vector routing

21. One node in each system called autonomous system speaker node Speaker node creates a routing table and advertises to the speaker node in neighbouring ASs

22. Path Vector Routing

23. OSPF

24. Unicasting

25. Multicasting

26. Multiple unicasting